Atmospheric Environment (v.71, #C)

Indoor aldehydes concentration and emission rate of formaldehyde in libraries and private reading rooms by Jeonghoon Kim; Seojin Kim; Kiyoung Lee; Dongwon Yoon; Jiryang Lee; DaeYoung Ju (1-6).
Aldehydes are of particularly interest due to their potential adverse impact on human health. Formaldehyde is one of the most abundant indoor pollutants. To improve indoor air quality, identifying and removing the major emission sources of formaldehyde would be desirable. The purposes of this study were to determine aldehyde concentrations in libraries and reading rooms and to identify emission sources of formaldehyde in private reading rooms. Indoor aldehyde concentrations were quantified at 66 facilities, including public libraries, children's libraries, public reading rooms, and private reading rooms, in the Seoul metropolitan area. Emission fluxes of formaldehyde from the surfaces of desks, chairs, floors, walls, and ceilings in 19 private reading rooms were measured using a passive emission colorimetric sensor. Indoor aldehyde (formaldehyde, acetaldehyde, propioaldehyde, benzaldehyde, and hexaldehyde) levels were significantly higher than outdoor levels. Indoor formaldehyde geometric mean concentrations in private reading rooms (119.3 μg m 3) were significantly higher than in public libraries (29.2 μg m 3), children's libraries (29.3 μg m 3), and public reading rooms (40.8 μg m 3). Indoor formaldehyde levels were associated with relative humidity. In private reading rooms, the emission rates from desks (255.5 ± 214.8 μg h 1) and walls (231.7 ± 192.3 μg h 1) were significantly higher than that from chairs (79.6 ± 88.5 μg h 1). Desks (31%) and walls (29%) were the major emission sources of formaldehyde in 14 facilities in which measurements exceeded the indoor standard of 100 μg m 3. The age of interior materials was a significant factor for indoor formaldehyde emission flux. Controlling the emission rates of desks and walls is recommended to improve formaldehyde concentrations in private reading rooms.► Indoor aldehydes levels in libraries are higher than outdoor levels. ► Indoor formaldehyde in private reading room is significantly high. ► Desk is the most significant source of formaldehyde in private reading rooms. ► Desk and building materials should be controlled for formaldehyde.
Keywords: Aldehydes; Formaldehyde; Emission flux; Emission rate; Libraries; Private reading rooms;

Aeolian dust as a transport hazard by M.C. Baddock; C.L. Strong; P.S. Murray; G.H. McTainsh (7-14).
The effects of blowing dust on transport operations are often mentioned as one of the significant impacts of aeolian processes on human welfare. However, few studies have been presented to demonstrate this impact. This research examined official air traffic incident reports in Australia for inclusively 1969–2010 to characterise the hazard of blowing dust to aviation in the country, the first such study of its kind. For the 42 year record, 61 incidents were identified (mean 1.4 per annum), with the large majority occurring in the first half of the 1970s. Only 20% of incidents occurred from 1984 onwards. Australian dust activity has not decreased over time, and the reduction in incidents is partly explained by improvements in aviation technology. The centralisation of Air Traffic Control operations to major coastal cities may however have reduced pilot reporting of dust-induced aviation incidents. By type of dust activity, dust storms were associated with nearly half of the reported incidents and dust hazes produced around a quarter. Only 5% of incidents resulted in any physical damage to aircraft and only one case involving personal injury was reported. The majority of the adverse effects on aviation due to dust (nearly 60% of reported incidents) were related to difficulties for navigation and completion of scheduled journey. Since aircraft damage and bodily harm were rare, the impact of dust in Australia is mostly that of inconvenience and associated raised economic costs. From 1990, the temporal pattern of incidents does not show any significant increase despite several intensely dusty years associated with recent droughts. This suggests that Australian aviation safety may be relatively resistant to the adverse effects of atmospheric dust as a hazard.► This paper examines official air transport incidents in Australia related to blowing dust. ► Over the 42 year period 1969–2010, there were 61 incidents connected to aeolian dust. ► Only 5% of incidents involved damage to aircraft or people, and there were no reported deaths. ► Almost two thirds of the dust-caused air safety issues related to navigational problems. ► Atmospheric dust represents at worst an inconvenience and economic cost to Australian aviation.
Keywords: Duststorm; Sandstorm; Air safety; Aerosols; Visibility; Eolian;

Size-segregated chemical composition of aerosol emissions in an urban road tunnel in Portugal by Casimiro Pio; Fátima Mirante; César Oliveira; Manuel Matos; Alexandre Caseiro; Cristina Oliveira; Xavier Querol; Célia Alves; Natércia Martins; Mário Cerqueira; Filomena Camões; Hugo Silva; Feliciano Plana (15-25).
An atmospheric aerosol study was performed in 2008 inside an urban road tunnel, in Lisbon, Portugal. Using a high volume impactor, the aerosol was collected into four size fractions (PM0.5, PM0.5–1, PM1 2.5 and PM2.5 10) and analysed for particle mass (PM), organic and elemental carbon (OC and EC), polycyclic aromatic hydrocarbons (PAH), soluble inorganic ions and elemental composition. Three main groups of compounds were discriminated in the tunnel aerosol: carbonaceous, soil component and vehicle mechanical wear. Measurements indicate that Cu can be a good tracer for wear emissions of road traffic. Cu levels correlate strongly with Fe, Mn, Sn and Cr, showing a highly linear constant ratio in all size ranges, suggesting a unique origin through sizes. Ratios of Cu with other elements can be used to source apportion the trace elements present in urban atmospheres, mainly on what concerns coarse aerosol particles.► Carbonaceous aerosol depends from engine regime and does not correlate with other constituents. ► Trace elements are associated with road dust emissions and mechanical disaggregation. ► Cu seems to be a good tracer for car emissions.
Keywords: Road vehicle aerosol emissions; Road tunnel experiments; Aerosol size segregated composition; Carbonaceous aerosol; Trace elements; Soluble ions;

Source contributions to PM2.5 and PM10 at an urban background and a street location by M.P. Keuken; M. Moerman; M. Voogt; M. Blom; E.P. Weijers; T. Röckmann; U. Dusek (26-35).
The contribution of regional, urban and traffic sources to PM2.5 and PM10 in an urban area was investigated in this study. The chemical composition of PM2.5 and PM10 was measured over a year at a street location and up- and down-wind of the city of Rotterdam, the Netherlands. The 14C content in EC and OC concentrations was also determined, to distinguish the contribution from “modern” carbon (e.g., biogenic emissions, biomass burning and wildfires) and fossil fuel combustion. It was concluded that the urban background of PM2.5 and PM10 is dominated by the regional background, and that primary and secondary PM emission by urban sources contribute less than 15%. The 14C analysis revealed that 70% of OC originates from modern carbon and 30% from fossil fuel combustion. The corresponding percentages for EC are, respectively 17% and 83%. It is concluded that in particular the urban population living in street canyons with intense road traffic has potential health risks. This is due to exposure to elevated concentrations of a factor two for EC from exhaust emissions in PM2.5 and a factor 2–3 for heavy metals from brake and tyre wear, and re-suspended road dust in PM10. It follows that local air quality management may focus on local measures to street canyons with intense road traffic.► Urban PM emissions contribute less than 15% to the urban background. ► Factor 2–3 higher EC, heavy metals and re-suspension concentrations in street canyons. ► 14C analysis indicates increasing contribution of biomass and biofuel to EC.
Keywords: PM; Air quality; Traffic emissions; 14C; Rotterdam; The Netherlands;

This study encompasses columnar ozone modelling in the peninsular Malaysia. Data of eight atmospheric parameters [air surface temperature (AST), carbon monoxide (CO), methane (CH4), water vapour (H2Ovapour), skin surface temperature (SSKT), atmosphere temperature (AT), relative humidity (RH), and mean surface pressure (MSP)] data set, retrieved from NASA's Atmospheric Infrared Sounder (AIRS), for the entire period (2003–2008) was employed to develop models to predict the value of columnar ozone (O3) in study area. The combined method, which is based on using both multiple regressions combined with principal component analysis (PCA) modelling, was used to predict columnar ozone. This combined approach was utilized to improve the prediction accuracy of columnar ozone. Separate analysis was carried out for north east monsoon (NEM) and south west monsoon (SWM) seasons. The O3 was negatively correlated with CH4, H2Ovapour, RH, and MSP, whereas it was positively correlated with CO, AST, SSKT, and AT during both the NEM and SWM season periods. Multiple regression analysis was used to fit the columnar ozone data using the atmospheric parameter's variables as predictors. A variable selection method based on high loading of varimax rotated principal components was used to acquire subsets of the predictor variables to be comprised in the linear regression model of the atmospheric parameter's variables. It was found that the increase in columnar O3 value is associated with an increase in the values of AST, SSKT, AT, and CO and with a drop in the levels of CH4, H2Ovapour, RH, and MSP. The result of fitting the best models for the columnar O3 value using eight of the independent variables gave about the same values of the R (≈0.93) and R 2 (≈0.86) for both the NEM and SWM seasons. The common variables that appeared in both regression equations were SSKT, CH4 and RH, and the principal precursor of the columnar O3 value in both the NEM and SWM seasons was SSKT.► A model for prediction of the value of atmospheric columnar ozone (O3). ► The O3 was negatively correlated with CH4, H2O vapour, RH, and MSP. ► The O3 was positively correlated with CO, AST, SSKT, and AT. ► Close agreement between the predicted and the AIRS observed data for columnar O3. ► AIRS data are suitable used to investigate the impact of atmosphere parameters.
Keywords: Ozone (O3); Regression analysis; Principal component analysis; Atmosphere infrared sounder (AIRS);

Surface ozone concentration and its behaviour with aerosols in the northwestern Himalaya, India by Priyanka Sharma; Jagdish Chandra Kuniyal; Kesar Chand; Raj Paul Guleria; Pitamber Prasad Dhyani; Chetan Chauhan (44-53).
Surface ozone (O3), black carbon (BC) concentration and their relationship were established with PM10 and PM2.5 mass concentration at Mohal (31.9°N, 77.12°E, 1154 m amsl), a semi-urban site, in the Kullu valley of the northwestern part of the Indian Himalaya during January to December, 2010. O3 showed highest diurnal variation (84 ppb) during daytime and lowest (10 ppb) during late evening as well as early morning hours. The maximum concentration of O3 during summer was influenced by meteorological parameters, high insolation and backward airmass trajectories with transported pollutants. Rate of increase of O3 was observed as high as 2.92 ppb h−1 in October, followed by 2.73 ppb h−1 in March and 2.71 ppb h−1 in May. However, it was low 1.89 ppb h−1 in February. Monthly average concentration of O3 showed distinct seasonal variations with maximum in summer (55.9 ± 9.3 ppb in May) and minimum in winter (30.0 ± 6.2 ppb in January). Most of the O3 episodes were observed in summer during fair weather conditions like high solar flux (480–500 W m−2), relatively high temperature (22–24 °C) and negligible rainfall. By applying backward trajectory Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the origin of the airmasses contributing to the background O3 concentration was investigated. O3 showed negative correlation with BC (r = −0.42). BC contributed 10–20% and 14–42% to the total aerosol mass concentration of PM10 and PM2.5 respectively which showed positive correlation (r = 0.65) with PM10 as well as PM2.5 aerosol mass concentration.► Surface ozone behaviour with black carbon, PM10 and PM2.5 were measured first time in the northwestern Indian Himalayan region. ► The maximum photochemical build-up of surface ozone was 14.7 ppb in May. ► Highest hourly concentrations of surface ozone were measured up to 126 ppb in May. ► Black carbon showed negative correlation with surface ozone and positive with PM10 and PM2.5. ► Monthly variation of BC/PM10 and BC/PM2.5 was maximum in September.
Keywords: Surface ozone; Photochemical pollution; BC; PM10; PM2.5; Indian Himalaya;

Studies have linked exposure to air pollutants to short-term and sub-chronic health outcomes. However, individual-level air pollution exposure is difficult to measure at a high spatial and temporal resolution and for larger populations due to limitations in sampling techniques. We presented a hierarchical model to capture spatiotemporal variability of nitrogen dioxide (NO2) and nitrogen oxides (NO x ) concentrations in Southern California by combining high temporal resolution data from routine monitoring stations with high spatial resolution data from investigator-initiated episodic measurements. In this model, the spatiotemporal field of concentrations was first decomposed into a mean and residual and the mean representing the seasonal trend was further decomposed into a constant and varying temporal basis functions. The mean of the spatially varying coefficients of temporal basis functions were modeled by local covariates using non-linear generalized additive model and least square fitting using measurements from both routine monitoring and additional episodic sampling locations, while the spatially-correlated residuals of the coefficients were co-kriged. We found traffic, land-use and wind accounted for a large portion of the variance (beyond 35%) for the long-term average trend of concentrations. Spatial residuals accounted for a large portion of the variance of the temporal components (about 30% for NO2 and 20% for NO x ). Leave-one-out cross validation produced an R 2 of 0.84 for NO2 and 0.81 for NO x when comparing the modeled weekly concentration with the observed trends at all routine monitoring stations.► Hierarchical spatiotemporal model predicted weekly NO2 and NO x concentrations well. ► Episodic measurements supplemented routine time-series measurements in modeling. ► Land-use, meteorology, and roadway were important in concentration prediction.
Keywords: Spatiotemporal variability; Temporal trend; Air pollution; Generalized additive model; Nitrogen dioxide; Nitrogen oxides;

The study investigates thermal stratification effects of approach flows on dispersion in urban environments. This is in some ways analogous to a well-developed non-neutral flow (e.g. through a large urban area) approaching a neighbourhood-scale urban region, where the effect of the local heat transfer was assumed less important. A generic urban-type geometry, i.e. a group of staggered cubes, was taken as the first test case. The DAPPLE site, which was about a one-km2 region near the intersection of Marylebone Road and Gloucester Place in central London, was taken as the second test case. Only weakly unstable conditions (i.e. bulk Richardson number R b ≥ − 0.2 ) of approach flows were considered, with adiabatic boundary conditions at the ground and building surfaces. A number of numerical experiments were performed. The modelled mean concentration for R b = −0.1 gave the best agreement with the field data at all DAPPLE stations. This suggests that stratification effects on dispersion in weakly unstable conditions (e.g. in London) are not negligible.► Effect on flows of weakly unstable conditions is greater than that of weakly stable. ► Concentration can be one order different under different stratification conditions. ► Effect of weakly unstable stratification on dispersion is not negligible.
Keywords: Thermal stability; Wind variation; Dispersion; Urban environments;

A new approach to estimate pollutant emissions based on trajectory modeling and its application in the North China Plain by W.Y. Xu; C.S. Zhao; L. Ran; Z.Z. Deng; N. Ma; P.F. Liu; W.L. Lin; P. Yan; X.B. Xu (75-83).
Emission information is crucial for air quality modeling and air quality management. In this study, a new approach based on the understanding of the relationship between emissions and measured pollutant concentrations has been proposed to estimate pollutant emissions and source contributions. The retrieval can be made with single point in-situ measurements combined with backward trajectory analyses. The method takes into consideration the effect of planetary boundary layer height on pollutant mixing and transport. It is independent of energy statistics and therefore can provide frequent updates on emission information. The spatial coverage can be further improved by using measurements from several sites and combining the derived emission fields. The method was applied to yield the source distributions of black carbon (BC) and CO in the North China Plain (NCP) using in-situ measurements from the HaChi (Haze in China) Campaign and to evaluate contributions from specific areas to local concentrations at the measurement site.Results show an emission field for the NCP that is comparable to the INTEX-B inventory can be retrieved and directly applied to quantify areal source contributions. Compared to emissions in 2006, increased CO and BC emissions were found. Uncertainty analyses show that in-situ measurements of CO and BC bear errors below 0.1 ppm and 12%, respectively. WRF model underestimates the PBLH under stable conditions. On average, an error of 1% in the modeled PBLH results in 1% variation in the derived emissions. The trajectory displacement errors are mostly within 1.5 times the grid size.► A new method for air pollutant emission retrieval. ► The calculated emissions can be easily updated using long-term datasets. ► The method is most suitable for heavy polluted regions.
Keywords: Emission; Source; Trajectory; Retrieval; Black carbon; Carbon monoxide;

Critical assessment of air pollution by ANOVA test and human health effects by Allaa M. Aenab; S.K. Singh; Ali Jabir Lafta (84-91).
Purposes of this study evaluate air quality by analysis of heavy metals (Ni, Cu and Pb) using ANOVA two-way test (space and time) within Baghdad city. Samples were collected from 3 stations in Baghdad city for 2 years (2009 & 2010). Concentrations (lead) were mostly exceeding the specific proposed national lead = 2 μg m−3, nickel was exceeded for the specific (1) mcg m−3. That of the causes of increased concentrations of heavy metals in the air is the occurrence of dust storms which carry dust storms amounts of dust containing heavy metals from the surface of land passing through, causing high concentrations of total suspended particles and that was mostly exceeding the specific national proposal and thus increasing the concentrations of heavy metals. Which indicates the possibility that the dust raised by wind erosion, which led to high concentrations of total suspended particles are the soils coming from the industrial areas is most likely because it is loaded at rates greater than the concentrations of heavy metals originating in industry. In sum, more than 50% of the concentrations of as exceeding the specified or exceeding the rates for the public.► We evaluate air pollution in Baghdad city. ► We examine heavy metals (Ni, Cu & Pb) and we found that, it is one of the reasons of air pollution in Baghdad city. ► We used ANOVA two-ways test for this study with respect for space and time. ► All the cases where F2 < F < F1 the variance has consistent values and for any other condition the test fails.
Keywords: Ni; Cu; Pb; Air pollution; Environmental pollution; Heavy metals; Health and population exposure;

Cr speciation changes in the presence of ozone and reactive oxygen species at low relative humidity by Mehdi Amouei Torkmahalleh; Lin Lin; Thomas M. Holsen; Don H. Rasmussen; Philip K. Hopke (92-94).
There is limited understanding of chromium chemistry in the atmosphere as well as after particles containing chromium are captured on filters during extended sampling intervals (24 h). Thus, experiments were conducted to investigate the role of ozone (4 ppm) and particle-bound reactive oxygen species (ROS) (>700 nM of equivalent H2O2) on chromium speciation. For Cr(VI) collected on a filter, reduction to Cr(III) at 24 °C, pH 4 and 10% RH decreased from 48 ± 3% to 26 ± 3% (p < 0.001) after 2 h of exposure, compared to the absence of added ozone (control experiments). Ozone and ROS led to some oxidation of Cr(III) to Cr(VI) (up to 7% for ozone at pH 4, up to 4.5 times for ROS and ozone at pH 9) with a steady-state concentration being reached after few hours. Ozone and ROS can compensate to some extent for Cr(VI) reduction occurring on PM-laden filters. Oxidation of Cr(III) by ozone slowed as the temperature decreased, implying that Cr(VI) sampling in a cool environment might be less likely biased by the oxidation of Cr(III) by atmospheric oxidants.
Keywords: Chromium; Ozone; ROS; Conversion; Sampling; Cr(VI); Cr(III);

Atmospheric amines – Part III: Photochemistry and toxicity by DongYoub Lee; Anthony S. Wexler (95-103).
Approximately 150 amines have been identified in the atmosphere but relatively little is known about their atmospheric photochemistry. In Part I and II of this work (Ge et al., 2011a,b), the present knowledge of the sources, fluxes, and dynamics of atmospheric amines was reviewed based upon a survey of the literature. In this work we compile published data for the gas phase atmospheric reaction rates of amines and products from these reactions. All available amine photochemical reaction data are summarized including reaction rates with OH, O3, NO3 radicals, and Cl atoms and photolysis. Toxicity and atmospheric lifetime of these amines and their reaction products are also reported with the goal of estimating of potential health hazards of atmospheric amines.► Relatively little is known about amine atmospheric photochemistry. ► We compile published data for the gas phase atmospheric reaction rates of amines and products from these reactions. ► Toxicity and atmospheric lifetime of these amines and their reaction products are also reported.
Keywords: Atmospheric amines; Photochemistry; Toxicity; Lifetime; Amine reaction products;

A study of O3 and NO2 vertical structure in a coastal wooded zone near a metropolitan area, by means of DOAS measurements by Margherita Premuda; Andrea Petritoli; Samuele Masieri; Elisa Palazzi; Ivan Kostadinov; Daniele Bortoli; Fabrizio Ravegnani; Giorgio Giovanelli (104-114).
The possible influence on the Castel Porziano Presidential Estate pine forest (Italy) of pollutant-rich air masses from the neighboring metropolitan area of Rome is analyzed. This study aims to highlight the consequences which this natural reserve located along the coast may suffer due to the vicinity of the metropolitan area. Two case studies, one representative of synoptic and the other of breeze patterns, are presented and analyzed to evaluate how the local wind circulation can influence these processes of mutual interaction between the wooded and the urban area nearby. This is a common situation in many other places around the world.To this end an up-to-date version of a method for gas profile retrieval in the lower troposphere, developed by the authors, is exploited to study the time evolution of the vertical structure of O3 and NO2 concentrations on the Estate. The method consists of applying an inversion technique, based on the weighted Chahine algorithm, to DOAS (Differential Optical Absorption Spectroscopy) remote-sensing measurements.The analysis of the retrieved vertical profiles shows that the degradation process associated with the arrival of air masses rich in photo-chemical pollutants, due to breeze circulation modified by the Coriolis Effect, is more apparent at upper levels than near the surface, affecting to a greater degree the higher branches of the trees. The paper also examines the impact of O3 on the wooded part of the Castel Porziano Estate. The incidence of this effect is evaluated with the analysis of the so-called AOT40 parameter.► The impact on a coastal pine forest of a nearby metropolitan area is analyzed. ► Cases of synoptic or breeze patterns are considered. ► An up-to-date version of our gas profiles retrieval method is used in the PBL. ► The effect of the arrival of polluted air masses is more apparent at upper levels. ► The ozone impact on the pine forest is evaluated with the “AOT40” parameter.
Keywords: Photo-chemical effect; Coastal pollution; Profile retrieval; Inversion methods; MAX-DOAS;

Estimates of methane wildfire emissions from Northeast Eurasia for years 2000–2011 are reported on the basis of satellite burned area data from the Moderate Resolution Imaging Spectroradiometer (MODIS MCD45 data product) and ecosystem-dependent fire emission parameters. Average (with standard deviations) emissions are 1.0 ± 0.2 Tg CH4 year−1, with interannual variations of 0.4–2.3 Tg CH4 year−1. Most of the emissions are located within 48–55°N, in the southern part of the boreal forest zone, mostly in Siberia and Far East. The largest discrepancies among independent present-day estimates are found in the sub-polar regions of West Siberia and Far East (60–65°N). Compared to the methane wetland emissions reported in literature, the wildfire emissions in the south add about 5–20% to their estimated average annual values and are compared with the magnitudes of their interannual variability. Average seasonal cycle peaks in April–May and July–August, which partially overlaps the summertime peak in wetland emissions. The independent estimates from version 3 of Global Fire Emissions Database (GFED3) are by 50% higher (compared to this study) for average annual emissions over the decade (which is quite good regarding the uncertainties) and showed larger differences for individual years. Possible applications of the results are considered for climate research and inverse modeling studies, as well as for assessment of the uncertainties in the present-day wildfire emission estimates.► Methane wildfire emissions are estimated and compared to independent results. ► Within 48–55°N, wildfires may add 5–20% annually to wetland emissions. ► At higher latitudes, the present-day estimates are most variable (uncertain). ► Observations of atmospheric methane in 30–60°N are required for further refinement.
Keywords: Methane emissions; Biomass burning; Satellite observations; Boreal forest;

Chemical characteristics of air masses from different urban and industrial centers in the Huabei region of China by Min Xue; Jianzhong Ma; Yi Li; Shuai Zhu; Bin Zhao; Peng Yan; Guoan Ding; Ruijun Jin (122-130).
North China, or Huabei in Chinese, is one of the most severely polluted regions in China. There are many large, complex and strong emission sources in Beijing, Tianjin and Tangshan (together called Jing-Jin-Tang in Chinese) and other urban and industrial centers in Huabei, and the chemical characteristics of air masses coming from these pollution centers are expected to be quite different. As part of the project “Influence of Pollution on Aerosols and Cloud Microphysics in North China (IPAC-NC)”, surface ozone and related trace gases were measured at the Xin'an rural station (39.73°N, 117.51°E), located in the central part of larger Jing-Jin-Tang area, during 2 April-16 May 2006. Here we investigate the chemical characteristics and impact of air masses from these different pollution hotspots on the regional distributions of ozone and nitrogen oxides in Huabei, based on measurement data as well as a regional chemical transport model. Simulated reactive nitrogen compounds are attributed to the different emission sources in the Huabei region using the tracer-tagging method implemented in the model. We find that the chemical characteristics of pollution plumes from different urban and industrial centers are rather different. The OPE x , defined as ozone production efficiency of nitrogen oxides (NO x ), for general pollution plumes from Beijing, Tianjin, Tangshan and Shijiazhuang are estimated to be 3.35, 2.75, 1.43 and 2.33 mol mol−1, respectively. During the IPAC-NC field campaign period, the Xin'an site was influenced alternatively by air masses from Beijing and Tianjin megacities and the Tangshan industrial area. The estimated OPE x in Beijing, Tianjin and Tangshan air masses arriving at Xin'an are comparable to those in their general pollution plumes. This indicates that air masses from different urban and industrial centers in Huabei also maintain their different chemical characteristics while being transported to the rural areas.► The tracer-tagging technique was applied in a regional chemical transport model. ► Chemical characteristics of plumes from major cities in Huabei were investigated. ► OPE x in the plumes from different urban and industrial centers are very different.
Keywords: Source emissions; Pollution plumes; Photochemical smog; Ozone production efficiency; Tracer-tagging method;

Spatial and temporal variability of PM10 sources in Augsburg, Germany by Jianwei Gu; Jürgen Schnelle-Kreis; Mike Pitz; Jürgen Diemer; Armin Reller; Ralf Zimmermann; Jens Soentgen; Annette Peters; Josef Cyrys (131-139).
Source apportionment of ambient particulate matter (PM10) was carried out using daily chemical composition data collected in winter 2006/07 and winter 2007/08 in Augsburg, Germany. Six factors have been identified and were associated with secondary nitrate, secondary sulfate, residential and commercial combustion, NaCl, re-suspended dust and traffic emissions. Comparing the source profiles between winter 2006/07 and winter 2007/08 showed that they were similar for both winters, except the combustion and traffic emissions factors. The spatial variation of particulate sources was evaluated by analysis of data collected at eight sampling sites during a one-month intensive campaign in winter 2007/08. Secondary nitrate, secondary sulfate as well as residential and commercial combustion factors showed strong correlations and low coefficient of divergence (COD) values among eight sites, indicating that they are uniformly distributed in urban area. By contrast, traffic emissions factor and NaCl were highly heterogeneously distributed. These two factors were enhanced greatly at the traffic site and are the cause of elevated PM10 mass concentration at traffic site. It means that for some specific sources of particles showing pronounced spatial variability a central monitoring site could not assess the absolute concentrations across an urban area. Thus, cautions should be taken when approximating average human exposure to these particle sources in long-term epidemiological studies.► Six particulate sources were identified in Augsburg using PMF method. ► Combustion and traffic source profiles had larger differences between two winters. ► Particulate sources of different origins showed distinct spatial variability. ► Traffic source was the main cause of elevated PM10 concentrations at traffic site.
Keywords: Source apportionment; Particulate matter; PMF; Spatial variability; Augsburg;

Spatial sensitivities of human health risk to intercontinental and high-altitude pollution by Jamin Koo; Qiqi Wang; Daven K. Henze; Ian A. Waitz; Steven R.H. Barrett (140-147).
We perform the first long-term (>1 year) continuous adjoint simulations with a global atmospheric chemistry–transport model focusing on population exposure to fine particulate matter (PM2.5) and associated risk of early death. Sensitivities relevant to intercontinental and high-altitude PM pollution are calculated with particular application to aircraft emissions. Specifically, the sensitivities of premature mortality risk in different regions to NO x , SO x , CO, VOC and primary PM2.5 emissions as a function of location are computed. We apply the resultant sensitivity matrices to aircraft emissions, finding that NO x emissions are responsible for 93% of population exposure to aircraft-attributable PM2.5. Aircraft NO x accounts for all of aircraft-attributable nitrate exposure (as expected) and 53% of aircraft-attributable sulfate exposure due to the strong “oxidative coupling” between aircraft NO x emissions and non-aviation SO2 emissions in terms of sulfate formation. Of the health risk-weighted human PM2.5 exposure attributable to aviation, 73% occurs in Asia, followed by 18% in Europe. 95% of the air quality impacts of aircraft emissions in the US are incurred outside the US. We also assess the impact of uncertainty or changes in (non-aviation) ammonia emissions on aviation-attributable PM2.5 exposure by calculating second-order sensitivities. We note the potential application of the sensitivity matrices as a rapid policy analysis tool in aviation environmental policy contexts.► The GEOS-Chem adjoint is used to quantify health risk from intercontinental pollution. ► Sensitivities of human health risk to aircraft pollution are calculated. ► >90% of aircraft emissions-related human PM exposure is due to NO x . ► Aircraft NO x creates half of aircraft-attributable surface sulfate. ► 95% of US aviation emissions-related health risk is incurred outside the US.
Keywords: Adjoint; Aircraft; Intercontinental pollution; Particulate matter; Health;

Particle-bound polycyclic aromatic hydrocarbon concentrations in transportation microenvironments by Douglas Houston; Jun Wu; Dongwoo Yang; Guillermo Jaimes (148-157).
This study is one of the first case studies to characterize the exposure of urban residents to traffic-related air pollution across locations and transportation microenvironments during everyday activities. Twenty-four adult residents of Boyle Heights, a neighborhood near downtown Los Angeles, carried a portable air pollution monitor and a Global Positioning Systems (GPS) tracking device for a total of 96 days. We found significant spatial and temporal variation in the particle-bound polycyclic aromatic hydrocarbon (pPAH) concentrations in transportation microenvironments. Average pPAH concentrations were higher while walking outdoors (190 ng m 3) compared to traveling in private passenger vehicles (138–155 ng m 3) or traveling in public transportation (61–124 ng m 3). Although travel comprised 5% of participant days, it was associated with 27% of overall daily pPAH exposure. Regression models explained 40–55% of the variation in daily average pPAH concentrations, and 40–44% of the variation in 1-min interval concentrations. Important factors included time spent traveling, travel speed, meteorological and nearby land use factors, time of day, and proximity to roadways. Although future research is needed to develop stronger predictive models, our study demonstrates portable tracking devices can provide a more complete, diurnal characterization of air pollution exposures for urban populations.► Examined exposure to particle-bound polycyclic aromatic hydrocarbon (pPAH). ► Concentrations varied significantly in transportation microenvironments. ► Travel comprised 5% of participant days and was associated with 27% of daily exposure. ► Exposures were highest while walking outdoors compared to other travel modes. ► Concentrations were associated with travel mode, time of day, meteorological, and nearby roadway and land use factors.
Keywords: Polycyclic aromatic hydrocarbon; PAH; Time activity; Exposure; Transportation;

Spatial variation of chemical constituents from the burning of commonly used biomass fuels in rural areas of the Indo-Gangetic Plain (IGP), India by T. Saud; M. Saxena; D.P. Singh; Saraswati; Manisha Dahiya; S.K. Sharma; A. Datta; Ranu Gadi; T.K. Mandal (158-169).
In the present paper, we have determined emission factor of chemical composition of the emission from the burning of biomass (e.g. Dung cake, Acacia, Neem, Mulberry, Indian Rosewood, Pigeon pea etc.) commonly used as a residential fuel in the rural sector of Indo-Gangetic Plain (IGP) (Delhi, Punjab, Haryana, Uttar Pradesh, Bihar and West Bengal), India. For comparison, we have selected only those biomass fuels, which are used in at least three of the above mentioned states. Dung cake from all the states reports highest emission of particulate matter (PM) (15.68 g kg−1), Organic Carbon (OC) (4.32 g kg−1) and Elemental Carbon (EC) (0.51 g kg−1). Among all biomass fuels studied, agricultural residue reports substantial amount of emission of Na+ (104 mg kg−1), K+ (331 mg kg−1) and Cl (447 mg kg−1) particularly in Pigeon pea and Mustard stem. Eucalyptus (fuel wood) emits large amounts of Ca2+ (21.47 mg kg−1) and NO3 (614 mg kg−1). The emission of PM from dung cake is higher in Delhi (19.31 g kg−1) and followed by Uttar Pradesh (17.58 g kg−1) > Haryana (15.46 g kg−1) > Bihar (14.99 g kg−1) > Punjab (12.06 g kg−1) > West Bengal (5.90 g kg−1). Carbonaceous aerosols (OC and EC) and dominant Ionic species (Cl, K+, SO4 2−, NO3 and PO4 3−) are altogether contributing 40–70% of total emissions. Characteristics and ratios of chemical species of emissions may help to develop a methodology of discriminating the sources of ambient particulate matter. Using a laboratory determined emission factor of chemical species, we have determined the emission budget over IGP, India.► Chemical characterisation of biomass burning emissions commonly used in IGP, India. ► Spatial variation of EF of same biomass used in different geographical locations. ► Determination of ratios (OC/EC, K+/EC, SO4 2−/EC) from biomass burning emissions. ► Emission estimation of ionic species from residential fuels used in IGP, India.
Keywords: Biomass fuel burning; Chemical constituents; Emission factor (EF); Spatial variation; Indo-Gangetic Plain;

Crop residue returning is a common practice in agricultural system that consequently influences nitrous oxide (N2O) emissions. Much attention has been focused on the effects of crop residue on N2O release. However, no systematic result has yet been drawn because environmental factors among different studies vary. A meta-analysis was described to integrate 112 scientific assessments of crop residue returning on N2O emissions in this study. Results showed that crop residue returning, when averaged across all studies, had no statistically significant effect on N2O release compared with control treatments. However, the range of effects of crop residue returning on N2O emission was significantly affected by synthetic nitrogen (N) fertilizer application, type of crop residue, specific manner in which crop residue has returned, and type of land-use. N2O release was significantly inhibited by 11.7% and 27.1% (P < 0.05) when crop residue was with synthetic N fertilizer and when type of land-use was paddy, respectively. While N2O emissions were significantly enhanced by 42.1% and 23.5% (P < 0.05) when crop residue was applied alone and when type of land-use was upland, respectively. N2O emissions were likewise increased when crop residue with lower C/N ratio was used, mulching of crop residue was performed, and type of land-use was fallow. Our study provides the first quantitative analysis of crop residue returning on N2O emissions, indicating that crop residue returning has no statistically significant effect on N2O release at regional scale, and underlining that the Intergovernmental Panel on Climate Change guidelines should take the opposite effects of crop residue returning on upland and paddy into account when estimating the N2O emission factor of crop residue for different land-use types. Given that most of data are dominated by certain types of crop residue and specific application methods, more field data are required to reduce uncertainty.► Effects of crop residue returning on N2O release are evaluated by meta-analysis. ► Crop residue returning has no obvious effect on N2O release compared with controls. ► Effects of crop residue on N2O emission is significantly affected by land-use types.
Keywords: Climate change; Nitrous oxide; Straw; Emission factor; Quantitative analysis;

The impact of long-range-transport on PM1 and PM2.5 at a Central Mediterranean site by M.R. Perrone; S. Becagli; J.A. Garcia Orza; R. Vecchi; A. Dinoi; R. Udisti; M. Cabello (176-186).
Water soluble ions, methanesulfonate, organic and elemental carbon, and metals in PM2.5 and PM1 samples were analysed by Positive Matrix Factorization to identify and quantify major sources of fine particles at a Central Mediterranean site. The cluster analysis of four-day back trajectories was used to determine the dependence of PM2.5 and PM1 levels and composition on air-flows. The cluster analysis has identified six, six, and seven distinct air-flow types arriving at 500, 1500, and 3000 m above sea level (asl), respectively. Slow-west (Wslow) and north-eastern (NE) flows at 500 and 1500 m asl were the most frequent and were associated with the highest PM2.5 and PM1 concentrations. The PM concentrations from combustion sources including biomass burning were at their maximum under north-western (NW) flows. Similarly, the ammonium sulphate source was enhanced under Wslow and NE flows. South-eastern Mediterranean Sea air-flows were associated with the highest PM2.5 concentrations due to the heavy-oil-combustion source and the highest PM2.5 and PM1 concentrations due to the secondary marine source. PM2.5 concentrations due to the reacted dust and traffic source and PM1 concentrations due to the nitrate with reacted dust and mixed anthropogenic source showed no clear dependence on air-flows. This work highlights the different impact of aerosol sources on PM2.5 and PM1 fractions, being PM1 more adequate to control anthropogenic emissions from combustion sources.► Chemical characterization of PM1 and PM2.5 samples at a Central Mediterranean site. ► PM source identification and quantification by Positive Matrix Factorization. ► Potential PM source location by back trajectory analysis. ► Cluster analysis of analytical back trajectories. ► Relations between PM sources and corresponding locations.
Keywords: Fine particulate; Chemical characterization; Positive Matrix Factorization; Long-range-transported contributions; Air-masses-back trajectory clustering;

Identification of potential source areas for elevated PM2.5, nitrate and sulfate concentrations by Jongbae Heo; Jerome E. McGinnis; Benjamin de Foy; James J. Schauer (187-197).
Extreme events or episodes of ambient fine particulate matter (PM2.5), in which daily mass concentrations are substantially higher than annual averages, have been frequently observed in southern Wisconsin, US. Determining the cause of events has been a great challenge to local governments responsible for protecting public health and complying with the 24-h PM2.5 standard. This study analyzed air parcel movements originating from emission source areas, and trends in PM2.5 concentrations in order to determine the important factors involved in elevated PM2.5 episodes in the region. A single backward trajectory analysis coupled with PM2.5 concentrations observed at Federal Reference Method Network (FRM) sites in Madison, Milwaukee and Waukesha; and nitrate and sulfate concentrations monitored at a Chemical Speciation Network (CSN) site in Milwaukee, Wisconsin, from 2002 to 2010 were examined. The PM2.5 concentrations from the FRM showed the total PM2.5 mass during the episodes were higher in Madison than in Milwaukee and Waukesha, while annual average concentrations were lower in Madison. However, the temporal trend in frequency of elevated PM2.5 episodes was remarkably similar across sites during the entire study period and high frequency episodes occurring from 2005 to 2007. Residence time analysis of backward trajectories calculated for all recorded data indicated episode changes were mainly driven by year-to-year variations of air mass movements originating in high emissions areas. Potential Source Contribution Function (PSCF) results showed the extreme events of PM2.5 occurred during times when trajectories passed over ammonia emissions hotspots as well as large stationary emissions. Enhanced nitrate and sulfate concentrations which were the major episode components were strongly influenced by air masses trajectories originating from the Ohio River Valley and adjacent states.► Effect of air parcel movements on variability in high PM2.5 episodes is evaluated. ► Variations of air masses originating in high emission areas influence the episodes. ► Trajectories from the Ohio River Valley enhance major episode components.
Keywords: Backward trajectory; PM2.5 episodes; PSCF; Ohio River Valley; Southern Wisconsin;

New Directions: Can a “blue sky” return to Indian megacities? by Prashant Kumar; Suresh Jain; B.R. Gurjar; Prateek Sharma; Mukesh Khare; Lidia Morawska; Rex Britter (198-201).
Deterioration of air quality in Indian megacities (Delhi, Mumbai or Kolkata) is much more significant than that observed in the megacities of developed countries. Densely packed high-rise buildings restrict the self-cleaning capabilities of Indian megacities. Also, the ever growing number of on-road vehicles, resuspension of the dust, and anthropogenic activities exacerbate the levels of ambient air pollution, which is in turn breathed by urban dwellers. Pollution levels exceeding the standards on a regular basis often result in a notable increase in morbidity and mortality. This article discusses the challenges faced by Indian megacities in their quest for sustainable growth, without compromising the air quality and urban way of life.
Keywords: Air Pollution; Clear air; Indian megacities; Particulate matter; Traffic emissions;

Single-particle fluorescence spectroscopy was used to study fluorescence properties of fungal spores and bacteria, selected for their possible atmospheric relevance. In addition, aromatic organic acid aerosols, potentially interfering with laser induced fluorescence measurement, were studied. The results indicate that fungal spores and bacteria have dissimilar fluorescence spectra. The tested aromatic organic acids had fluorescence properties rather similar to common biological molecules. It may be possible to classify atmospheric bacterial and fungal spores through the dissimilar fluorescence properties, but the influence of the potential interferences must be taken into account.► Fluorescence spectra were recorded from single fungal spores and bacteria. ► Fungal spores and bacteria seem to have dissimilar fluorescence spectra. ► Bacteria and fungal spores may be distinguished through the fluorescence spectra.
Keywords: Fluorescence; Spectroscopy; Fungal spores; Bacteria; PBAP;

Performance evaluation of chemistry transport models over India by K. Krishna Moorthy; S. Naseema Beegum; N. Srivastava; S.K. Satheesh; Mian Chin; Nadege Blond; S. Suresh Babu; S. Singh (210-225).
Using continuous and near-real time measurements of the mass concentrations of black carbon (BC) aerosols near the surface, for a period of 1 year (from January to December 2006) from a network of eight observatories spread over different environments of India, a space-time synthesis is generated. The strong seasonal variations observed, with a winter high and summer low, are attributed to the combined effects of changes in synoptic air mass types, modulated strongly by the atmospheric boundary layer dynamics. Spatial distribution shows much higher BC concentration over the Indo-Gangetic Plain (IGP) than the peninsular Indian stations. These were examined against the simulations using two chemical transport models, GOCART (Goddard Global Ozone Chemistry Aerosol Radiation and Transport) and CHIMERE for the first time over Indian region. Both the model simulations significantly deviated from the measurements at all the stations; more so during the winter and pre-monsoon seasons and over mega cities. However, the CHIMERE model simulations show better agreement compared with the measurements. Notwithstanding this, both the models captured the temporal variations; at seasonal and sub-seasonal timescales and the natural variabilities (intra-seasonal oscillations) fairly well, especially at the off-equatorial stations. It is hypothesized that an improvement in the atmospheric boundary layer (ABL) parameterization scheme for tropical environment might lead to better results with GOCART.► A space-time synthesis of aerosol black carbon is generated over India. ► The strong seasonal variations observed, with a winter high and summer low. ► Highest BC concentration was observed over the Indo-Gangetic Plain. ► Chemistry transport model simulations deviates from the measurements. ► An improvement in the ABL parameterization scheme might improve model predictions.
Keywords: Aerosols; Black carbon; Chemistry transport models;

Studies of size-resolved organic speciation of aerosols are still relatively rare and are generally only conducted over short durations. However, size-resolved organic data can both suggest possible sources of the aerosols and identify the human exposure to the chemicals since different aerosol sizes have different lung capture efficiencies. The objective of this study was to conduct size-resolved organic aerosol speciation for a calendar year in Phoenix, Arizona to determine the seasonal variations in both chemical concentrations and size profiles. The results showed large seasonal differences in combustion pollutants where the highest concentrations were observed in winter. Summertime aerosols have a greater proportion of biological compounds (e.g. sugars and fatty acids) and the biological compounds represent the largest fraction of the organic compounds detected. These results suggest that standard organic carbon (OC) measurements might be heavily influenced by primary biological compounds particularly if the samples are PM10 and TSP samples. Several large dust storms did not significantly alter the organic aerosol profile since Phoenix resides in a dusty desert environment, so the soil and plant tracer of trehalose was almost always present. The aerosol size profiles showed that PAHs were generally most abundant in the smallest aerosol size fractions, which are most likely to be captured by the lung, while the biological compounds were almost exclusively found in the coarse size fraction.Display Omitted► Organic pollutants have the highest concentrations in winter due to inversions. ► Dust storms did not significantly contribute to the organic aerosol composition. ► Most of the organic chemicals detected are harmless biological compounds. ► The size distribution of chemicals in aerosols is largely consistent over seasons.
Keywords: Particulates; PAH; Levoglucosan; Trehalose; Alkane; Phoenix; Coronene;

Size distribution and concentrations of heavy metals in atmospheric aerosols originating from industrial emissions as predicted by the HYSPLIT model by Bing Chen; Ariel F. Stein; Pabla Guerrero Maldonado; Ana M. Sanchez de la Campa; Yolanda Gonzalez-Castanedo; Nuria Castell; Jesus D. de la Rosa (234-244).
This study presents a description of the emission, transport, dispersion, and deposition of heavy metals contained in atmospheric aerosols emitted from a large industrial complex in southern Spain using the HYSPLIT model coupled with high- (MM5) and low-resolution (GDAS) meteorological simulations. The dispersion model was configured to simulate eight size fractions (<0.33, 0.66, 1.3, 2.5, 5, 14, 17, and >17 μm) of metals based on direct measurements taken at the industrial emission stacks. Twelve stacks in four plants were studied and the stacks showed considerable differences for both emission fluxes and size ranges of metals. We model the dispersion of six major metals; Cr, Co, Ni, La, Zn, and Mo, which represent 77% of the total mass of the 43 measured elements. The prediction shows that the modeled industrial emissions produce an enrichment of heavy metals by a factor of 2–5 for local receptor sites when compared to urban and rural background areas in Spain. The HYSPLIT predictions based on the meteorological fields from MM5 show reasonable consistence with the temporal evolution of concentrations of Cr, Co, and Ni observed at three sites downwind of the industrial area. The magnitude of concentrations of metals at two receptors was underestimated for both MM5 (by a factor of 2–3) and GDAS (by a factor of 4–5) meteorological runs. The model prediction shows that heavy metal pollution from industrial emissions in this area is dominated by the ultra-fine (<0.66 μm) and fine (<2.5 μm) size fractions.► We modeled the dispersion of heavy metals originating from industrial complex. ► The model was refined by configuration of eight size fractions of metals. ► High- and low-resolution meteorological models were compared. ► Model driven by MM5 had reasonable prediction of metal pollution. ► Industrial emissions enhanced metal pollution levels by a factor of 2–5.
Keywords: Metal pollution; Size distribution; Industrial emissions; HYSPLIT; MM5 and GDAS;

Synergistic ammonia losses from animal wastewater by Sang R. Lee; Scott R. Yates; Wayne P. Robarge; Scott A. Bradford (245-250).
Thin-layer models are commonly used to estimate NH3 emissions from liquid waste. However, such models differ in their ability to accurately reproduce observed emissions, which may be partly due to an incomplete mechanistic understanding of NH3 volatilization. In this study, NH3 release from pure solutions of (NH4)2SO4 (AS), swine pit liquid (PL), swine lagoon liquid (LL), dairy lagoon liquid (DLL), and dairy manure liquid (DML) were evaluated under controlled conditions (pH 7.6 and temperature 20 °C). Relationships between the NH3 release and pH, temperature, and total ammoniacal nitrogen (TAN) were established. Under similar TAN conditions, the NH3 release was higher for PL, LL, DLL, and DML than for AS. Pure solutions of AS that were spiked with NaHCO3 showed NH3 emissions rates that were comparable to DML, DLL, LL and PL. The enhanced NH3 emissions of PL, LL, DLL and DML were therefore explained by linkages between TAN and HCO3 .► Measured ammonia emissions from pure (NH4)2SO4 solution and animal wastewater. ► Observed enhanced ammonia emissions from both swine and dairy wastewater. ► Multiple reactions in animal wastewater control NH3 emissions across thin layers. ► Modeling application needs to go with better understanding of ammonia emissions.
Keywords: Ammonia; Carbon dioxide; Bicarbonate; Emissions; Thin-layer model; Swine lagoon; Dairy waste; Henry's law constant;

Nocturnal surface ozone enhancement and trend over urban and suburban sites in Portugal by Pavan S. Kulkarni; D. Bortoli; A.M. Silva (251-259).
Long term (2000–2010) analysis of hourly surface ozone data from 6 out of 9 background air pollution monitoring sites in Portugal shows prominent secondary/nocturnal peak in monthly averaged diurnal variation during winter months (Nov–Feb). Of 9 sites: 3 are urban, 5 suburban and 1 rural. The bimodal diurnal variation of surface ozone shows a major peak around 15 h and a minor peak around 03–05 h with minima around 08 h and 20 h in the months of November–February. During winter months, more than 50% of observations in Porto and Lisbon region had nocturnal surface ozone concentrations higher than 40 μg m−3 compared to monthly averaged early morning/late evening minima (20±5 μg m−3). Analysis also shows an increasing trend in nocturnal surface ozone daily maxima over 5 urban/suburban sites and over another site (Alfragide) which exhibits the same trend but only in the last 7 years of the studied period. Also the non-parametric Mann–Kendall test confirms that the trends are statistically significant. The enhancement of nocturnal surface ozone is most likely associated with transport process and prevailing meteorological conditions since photochemical production of ozone ceases after sunset.► Bimodal diurnal variation of surface ozone during winter months. ► Frequent enhancement of nocturnal surface ozone over urban/suburban background sites. ► Increasing trend of nocturnal surface ozone over Portugal.
Keywords: Nocturnal surface ozone; Bimodal diurnal variation; Trend; Mann–Kendall test;

Emissions and indoor concentrations of particulate matter and its specific chemical components from cooking: A review by Karimatu L. Abdullahi; Juana Maria Delgado-Saborit; Roy M. Harrison (260-294).
It has long been known that cooking can create high concentrations of aerosol indoors. Increasingly, it is now being reported that cooking aerosol is also a significant component of outdoor particulate matter. As yet, the health consequences are unquantified, but the presence of well known chemical carcinogens is a clear indication that cooking aerosol cannot be benign. This review is concerned with current knowledge of the mass concentrations, size distribution and chemical composition of aerosol generated from typical styles of cooking as reported in the literature. It is found that cooking can generate both appreciable masses of aerosol at least within the area where the cooking takes place, that particle sizes are largely within the respirable size range and that major groups of chemical compounds which have been used to characterise cooking aerosol include alkanes, fatty acids, dicarboxylic acids, lactones, polycyclic aromatic hydrocarbons, alkanones and sterols. Measured data, cooking emission profiles and source apportionment methods are briefly reviewed.Display Omitted► Cooking can generate appreciable aerosol within the area where cooking takes place. ► Cooking aerosol is largely within the respirable size range. ► Fatty acids and dicarboxylic acids are major components. ► Other constituents are alkanones, alkanals, lactones, PAH, sterols and alkanes. ► Raw food, cooking oil, cooking style and temperature affect aerosol composition.
Keywords: Cooking; Cooking aerosol; Cooking emissions; Cooking tracers;

Emission factors and detailed chemical composition of smoke particles from the 2010 wildfire season by Ana Vicente; Célia Alves; Ana I. Calvo; Ana P. Fernandes; Teresa Nunes; Cristina Monteiro; Susana Marta Almeida; Casimiro Pio (295-303).
This paper complements the information previously published (Atmospheric Environment 45, 641–649) on gaseous and particulate emissions from wildfires in Portugal for summer 2009, in an attempt at obtaining more extensive, complete and representative databases on emission factors and detailed chemical characterisation of smoke particles. Here, emission factors for carbon oxides (CO2 and CO), total hydrocarbons (THC), fine (PM2.5) and coarse (PM2.5–10) particles obtained for fires occurring in Portugal in summer 2010 are presented. The carbonaceous content (OC and EC), water-soluble ions, elements and organic composition of smoke particles were, respectively, analysed by a thermal-optical transmission technique, ion chromatography, instrumental neutron activation analysis (INAA) and gas chromatography-mass spectrometry (GC–MS). The particle mass concentrations were in the ranges 0.69–25 mg m−3 for PM2.5 and 0.048–3.1 mg m−3 for PM2.5–10. PM2.5 particles represented 91 ± 5.7% of the PM10 mass. The OC/EC ratios in fine and coarse particles ranged from 2.5 to 205 and from 1.7 to 328, respectively. The water-soluble ions represented, on average, 3.9% and 2.8% of PM2.5 and PM2.5–10 mass, respectively. In general, the dominant ions in the water extracts were Na+, NH 4 + , Cl and NO 3 − for the PM2.5 fraction, and K+, Mg2+, Ca2+ and SO 4 2 − for the PM2.5–10 fraction. The K+/EC and K+/OC ratios obtained in this study were, on average, 0.22 ± 0.23 and 0.011 ± 0.014 for PM2.5 and 0.83 ± 1.0 and 0.024 ± 0.023 for PM2.5–10 particles, respectively. The K+/levoglucosan ratio was, on average, 2.0 for PM2.5 and 3.1 for PM2.5−10 particles. Levoglucosan was detected at mass fractions of 1.6–8.7 mg g−1 OC in PM2.5 and 2.7–56 mg g−1 OC in PM2.5–10. The dominant elements detected in the smoke samples were Na, Br, Cr, Fe, K, Rb and Zn. The most representative organic constituents in the smoke samples were acids, alcohols, terpenoid-type compounds, sugars and phenols, in both size fractions.► Inorganic and organic speciation of smoke samples from wildfires is provided. ► Fine particles (PM2.5) represented about 90% of the PM10 mass. ► The water-soluble inorganic ions represented 3.9% of PM2.5 and 2.8% of PM2.5–10. ► On average, 89% of total potassium (PM2.5 + PM2.5–10) was present in PM2.5 particles. ► Major organic compounds in smoke samples were acids, anhydrosugars and phenol.
Keywords: Wildfires; Trace gases; Emission factors; Organic compounds; Water-soluble ions; Trace elements; Portugal;

A statistical model, based on numerical weather prediction (NWP), is developed to predict the subsequent day's satellite observations of fire activity in the North American boreal forest during the fire season (24-h forecast). In conjunction with the six components of the Canadian Forest Fire Danger Rating System and other NWP outputs, fire data from the MODerate Resolution Imaging Spectroradiometer (MODIS) and the Geostationary Operational Environmental Satellites (GOES) are used to examine the meteorological separability between the largest fire growth and decay events, with a focus on central Alaska during the large fire season of 2004. This combined information is analyzed in three steps including a maximum likelihood classification, multiple regression, and empirical correction, from which the meteorological effects on fire growth and decay are statistically established to construct the fire prediction model. Both MODIS and GOES fire observations show that the NWP-based fire prediction model is an improvement over the forecast of persistence commonly used by near-real-time fire emission inventories. Results from an independent test (2005 fire season) show that the root-mean-square error (RMSE) of predicted MODIS fire observations is reduced by 5.2% compared with a persistence forecast. Improvements are strongest (RMSE reduction of 11.4%) for cases with observed decay or extinction of fires. Similar results are obtained from additional independent tests using the 2004 and 2005 GOES satellite fire observations. This study uniquely demonstrates the value and importance of combining NWP data and satellite fire observations to predict biomass-burning emissions, which is a critical step toward producing a global short-term fire prediction model and improving operational forecasts of smoke transport at large spatial scales.► Statistical model predicts daily growth or decay of satellite-observed fires in central Alaska. ► Inputs include MODIS and GOES fire data and NWP-calculated fire weather indices. ► Reduces RMSE compared to a persistence forecast used by smoke emission inventories. ► Improvements are strongest for cases with observed decay or extinction of fires. ► Critical step toward improving operational smoke emission and transport forecasts.
Keywords: Fire weather; Numerical weather prediction; Satellite; Boreal; Wildfire; Smoke; Emissions; Statistics;

In this work, the impact of aerosols over ultraviolet-B at the Earth's surface (UVB) was studied. The estimations of aerosols radiative effects on UVB are significant to UVB estimations, air quality studies, as well as assessments of the impact of regional environmental change. The study used simultaneously hourly values of UVB, global solar radiation (G) at the horizontal surface and direct normal solar radiation (I n). In addition, other meteorological parameters such as air temperature (T), relative humidity (R) and cloudiness were collected. These data were measured at Qena, Egypt (26.20°N, 32.75°E, and 96 m amsl) through the period from 2001 to 2004. To analyze the relationship between UVB and aerosols, the dimensionless parameter UVB transmission (K tUVB) and Ångström turbidity coefficient (β) in cloudless conditions were considered. The results showed that there is no correlation between K tUVB and β in the wide range of SZA (3° > SZA < 75°). The change of K tUVB to change β was equal to −0.078 (the correlation coefficient, R = −0.22, i.e. 5% of the variability of K tUVB was explained by β). So, sensitivity analysis of aerosol effect in K tUVB to SZA was employed. The relationship between K tUVB and β was determined for a narrow ranges of SZA (the range is equal to 1°) and a linear regression was fitted for each range of SZA. The ΔK tUVB/Δβ, accordingly the correlation coefficient (R), increases with the increasing SZA, which means K tUVB becomes more sensitive to β as SZA increase. Datasets for each narrow range of SZA, which showed a correlation between K tUVB and β (−R > 0.50), were selected to quantify the relationship between both parameters. These selected datasets just show the effect of aerosols in K tUVB when their UVB penetrating influence is more than the influence of other atmospheric factors such as ozone, i.e. the effect of aerosols is to induce a notable reduction in K tUVB. For the selected datasets, ΔK tUVBβ varied from −0.05 to −0.21 and its average value was equal to −0.12. The resulting regression analysis showed that the determination coefficients of linear fit vary from 0.25 to 0.77, i.e. 25% to 75% of the variance in K tUVB was explained by β.► The aerosol effect in UVB transmission (K tUVB) was analyzed. ► Sensitivity analysis of aerosol effect in K tUVB to SZA was employed. ► The sensitivity of K tUVB to aerosols increases with increased SZA. ► For the cases under study, the aerosols reduce K tUVB from 5% to 21%. ► 25%–75% of the variance in K tUVB was explained by aerosols.
Keywords: Egypt; UVB solar radiation; Transmission of UVB; Aerosols; Ångström turbidity coefficient (β);

Oxalic acid is widely reported in the literature as one of the major components of organic aerosol. It has been reported as both a product of primary emissions from combustion processes and as a secondary product of atmospheric chemistry. Concentrations of particulate oxalate have been measured at a UK urban site (500 daily samples) and for a more limited period simultaneously at a rural site (100 samples) in the fine (less than 2.5 μm) and coarse (2.5–10 μm) size fractions. Full size distributions have also been measured by sampling with a MOUDI cascade impactor. Average concentrations of oxalate sampled over different intervals in PM10 are 0.04 ± 0.03 μg m−3 at the rural site and 0.06 ± 0.05 μg m−3 at the urban background site, broadly comparable with measurements from other European locations. During the period of simultaneous sampling at the urban and rural site, concentrations were very similar and the inter-site correlation in the PM2.5 fraction for oxalate (r = 0.45; p < 0.001) was appreciably weaker than that for sulphate and nitrate (r = 0.82 and 0.84, respectively). Nonetheless, the data clearly point to a predominantly secondary source of oxalate at these sites. Possible contributions from road traffic and woodsmoke appear to be very small. In the larger urban dataset, oxalate in PM2.5 was correlated significantly (p < 0.01) with sulphate (r = 0.60), nitrate (r = 0.48) and secondary organic carbon (r = 0.25). Clustering of air mass back trajectories demonstrates the importance of advection from mainland Europe. The size distribution of oxalate at the urban site showed a major mode at around 0.55 μm and a minor mode at around 1.5 μm in the mass distribution. The former mode is similar to that for sulphate suggesting either a similar in-cloud formation mechanism, or cloud processing of oxalate and sulphate after formation in homogeneous reaction processes.Display Omitted► Oxalate was measured at urban and rural sites. ► Inter-site and intra-site correlations indicate a predominantly secondary source. ► Emissions from traffic and biomass combustion are small. ► Trajectory clustering demonstrates advection from mainland Europe. ► Particle size distribution is similar to sulphate.
Keywords: Oxalate; Secondary organic aerosol; Regional pollution;

With the aim to investigate the main pollution characteristics of exhaust gases emitted from plastic waste recycling granulation plants, mainly volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) were analyzed in Xingtan Town, the largest distribution center of plastic waste recycling in China. Both inside and outside the plants, the total concentrations of volatile monocyclic aromatic hydrocarbons (MAHs), PAHs and PAEs ranged from 2000 to 3000 μg m−3, 450 to 1200 ng m−3, and 200 to 1200 ng m−3, respectively. Their concentration levels inside the plants were higher than those outside the plants, and PAHs and PAEs were mainly distributed in the gas-phase. Notably, highly toxic benzo[a]pyrene (BaP) could be detected inside the plants, and harmful PAEs could be detected not only inside but also outside the plants, although PAEs are non-volatile. The exhaust gas composition and concentration were related to the plastic feedstock and granulation temperature.► Exhaust gases emitted from plastic waste recycling plants were studied. ► Harmful VOCs, PAHs and PAEs could be detected both inside and outside the plants. ► Highly toxic BaP could be detected inside the plants. ► Exhaust gas composition was related to feedstock and granulation temperature.
Keywords: Exhaust gases; Plastic waste recycling; Volatile organic compounds; Polycyclic aromatic hydrocarbons; Phthalate esters;

Forecasting long-range atmospheric transport episodes of polychlorinated biphenyls using FLEXPART by Anne Karine Halse; Sabine Eckhardt; Martin Schlabach; Andreas Stohl; Knut Breivik (335-339).
The analysis of concentrations of persistent organic pollutants (POPs) in ambient air is costly and can only be done for a limited number of samples. It is thus beneficial to maximize the information content of the samples analyzed via a targeted observation strategy. Using polychlorinated biphenyls (PCBs) as an example, a forecasting system to predict and evaluate long-range atmospheric transport (LRAT) episodes of POPs at a remote site in southern Norway has been developed. The system uses the Lagrangian particle transport model FLEXPART, and can be used for triggering extra (“targeted”) sampling when LRAT episodes are predicted to occur. The system was evaluated by comparing targeted samples collected over 12–25 h during individual LRAT episodes with monitoring samples regularly collected over one day per week throughout a year. Measured concentrations in all targeted samples were above the 75th percentile of the concentrations obtained from the regular monitoring program and included the highest measured values of all samples. This clearly demonstrates the success of the targeted sampling strategy.► Long-range atmospheric transport episodes of PCBs were studied at Birkenes, Norway. ► Potential episodes were initially forecasted using the FLEXPART model. ► Targeted samples collected during individual episodes were analyzed. ► Strong pollution episodes of PCBs were identified. ► A forecast system as presented could add value to relevant monitoring efforts.
Keywords: Persistent organic pollutants; Birkenes; FLEXPART; Forecast; Episodes; Polychlorinated biphenyls;

Observations of new aerosol particle formation in a tropical urban atmosphere by Raghu Betha; Dominick V. Spracklen; Rajasekhar Balasubramanian (340-351).
Particle number concentrations (PNC) and particle size distributions (PSD) in the size range of 5.6–560 nm were measured in Singapore during South West (SW) and North East (NE) monsoon periods. The field study was conducted from 27 July 2008 to 15 August 2008 and from 21 January 2009 to 22 February 2009. A distinct peak of PNC in the afternoon was observed in addition to morning and evening rush hour peaks during the SW monsoon period. Concurrent measurements of PSD, SO2, Black Carbon (BC) and proxy H2SO4 concentrations revealed that the afternoon peaks observed during the SW monsoon period were likely due to new particle formation. These nucleation events were frequently observed during the SW monsoon period, but were rarely seen during the NE monsoon period. The effect of meteorological parameters viz. Temperature (T), Relative Humidity (RH), Incoming Solar radiation (SR) on the rate and intensity of nucleation was examined. Strong nucleation events were observed in the presence of high H2SO4 concentrations at high T, high SR, and low RH. The newly formed particles did not show any signs of growth during the nucleation events. New particle formation (NPF) events appear to be mainly induced by SO2 emissions from the local point sources (e.g. petroleum refineries), so when winds blew from that direction nucleation events were prominent. Local bush fires were observed during the course of air sampling due to a prolonged dry spell in the months of January and February 2009. During the occurrence of the local smoke haze induced by bush fires, nucleation events were suppressed.► New particle formation (NPF) was observed in Singapore in the presence of high SO2 concentrations. ► NPF events occurred mainly in the afternoon in the presence of high sunlight. ► Meteorological parameters and pre-existing aerosol concentrations had a major influence on the rate of NPF and its intensity. ► Local bush fires were observed to suppress the NPF.
Keywords: Aerosols; Nucleation; Biomass burning; New particle formation; Urban atmosphere;

The impact of large scale biomass production on ozone air pollution in Europe by Joost B. Beltman; Carlijn Hendriks; Markus Tum; Martijn Schaap (352-363).
Tropospheric ozone contributes to the removal of air pollutants from the atmosphere but is itself a pollutant that is harmful to human health and vegetation. Biogenic isoprene emissions are important ozone precursors, and therefore future changes in land use that change isoprene emissions are likely to affect atmospheric ozone concentrations. Here, we use the chemical transport model LOTOS-EUROS (dedicated to the regional modeling of trace gases in Europe) to study a scenario in which 5% of the crop- and grass-land in Europe is converted into poplar plantations to be used for biofuel production. Although this scenario is rather conservative, our simulations project that isoprene emissions are substantially increased by an average of 45% over the simulated domain. As a consequence, ozone peak values are expected to increase by up to 6%, and ozone indicators for damage to human health and vegetation by up to 25% and 40%, respectively. Finally, we show that after the change in land use NO x emission reductions of 15–20% in Europe would be required to restore the ozone levels to current values. Because biomass production is expected to increase throughout Europe in the coming decades, we conclude that careful consideration of the tree types and regions to be used is required to constrain the concomitant air pollution to a minimum.► Future poplar biomass plantations may significantly impact ozone levels in Europe. ► Growing poplar on 5% of European farmland enhances isoprene emissions by 45%. ► Ozone indicators for human health and vegetation increase by up to 25% and 40%. ► Air pollution mitigation strategies should consider land use management.
Keywords: Ozone; Biomass plantations; Chemical transport model; Isoprene emissions; Poplar;

Commuters are regularly exposed to short-term peak concentration of traffic produced nanoparticles (i.e. particles <300 nm in size). Studies indicate that these exposures pose adverse health effects (i.e. cardiovascular). This study aims to obtain particle number concentrations (PNCs) and distributions (PNDs) inside and outside a car cabin whilst driving on a road in Guildford, a typical UK town. Other objectives are to: (i) investigate the influences of particle transformation processes on particle number and size distributions in the cabin, (ii) correlate PNCs inside the cabin to those measured outside, and (iii) predict PNCs in the cabin based on those outside the cabin using a semi-empirical model. A fast response differential mobility spectrometer (DMS50) was employed in conjunction with an automatic switching system to measure PNCs and PNDs in the 5–560 nm range at multiple locations inside and outside the cabin at 10 Hz sampling rate over 10 s sequential intervals. Two separate sets of measurements were made at: (i) four seats in the car cabin during ∼700 min of driving, and (ii) two points, one the driver seat and the other near the ventilation air intake outside the cabin, during ∼500 min of driving. Results of the four-point measurements indicated that average PNCs at all for locations were nearly identical (i.e. 3.96, 3.85, 3.82 and 4.00 × 104 cm−3). The modest difference (∼0.1%) revealed a well-mixed distribution of nanoparticles in the car cabin. Similar magnitude and shapes of PNDs at all four sampling locations suggested that transformation processes (e.g. nucleation, coagulation, condensation) have minimal effect on particles in the cabin. Two-point measurements indicated that on average, PNCs inside the cabin were about 72% of those measured outside. Time scale analysis indicated that dilution was the fastest and dominant process in the cabin, governing the variations of PNCs in time. A semi-empirical model was proposed to predict PNCs inside the cabin as a function of those measured outside. Performance evaluation of the model against multiple statistical measures was within the recommended guidelines for atmospheric dispersion modelling. Trip average PNCs obtained using the model demonstrate a reasonably good correlation (i.e. R 2 = 0.97) with measured values.► Pseudo-simultaneous measurements at all 4 seats in car, and inside–outside taken. ► Identical PNCs at all 4 seats indicated car cabin air is well-mixed. ► Ratio of in-cabin to outside PNCs is not uniform for different particle sizes. ► Time scale analysis highlights dilution as a dominating process. ► A proposed semi-empirical model predicted inside cabin PNC adequately well.
Keywords: Car cabin exposure; Nanoparticles dispersion; Number and size distribution; Transformation processes; Ultrafine particles;

Influence of an enhanced traffic volume around beaches in the short period of summer on ozone by Sang-Keun Song; Zang-Ho Shon; Yoo-Keun Kim; Yoon-Hee Kang; Ju-Hee Jeong (376-388).
The impact of pollutant emissions by the significant amount of road traffic around beaches on the ozone (O3) concentrations in the surrounding regions were evaluated using a numerical modeling approach during 6 days (29 July through 3 August) of the beach opening period (BOP) in 2010. On-road mobile emissions at several roads close to beaches in Busan, Korea during the study period were estimated from the emission factors, vehicle kilometers traveled, and deterioration factors. The emission data was then applied to the 3-D chemical transport model. A process analysis (PA) was also used to assess the contributions of the individual physical and chemical processes to the production or loss of O3 in the study area. The model study suggested the possibility that road traffic emissions near the beach area can have a significant impact on the O3 concentrations in the source regions as well as their surrounding/downwind regions. The maximum negative impact of mobile emissions on the O3 concentrations was predicted near the beach areas: by −9 ppb during the day due to both the high NO x emissions with the high NO x /VOC ratio and meteorological conditions and −9 ppb at night due to the fast titration of O3 by NO. The PA showed that the contribution of chemical process to the decrease in O3 concentrations (up to −5.5 ppb h−1) due to mobile emissions near the beach areas was the most dominant compared to the other physical processes.► We evaluated the impact of road traffic emissions around beaches on O3 concentrations. ► The analysis was based on a numerical modeling approach during the beach opening period. ► The maximum negative impact of mobile emissions was predicted near the beach areas. ► O3 destruction rate around the beach areas decreased by up to −5.5 ppb h−1 during the day.
Keywords: Beach; On-road mobile emission; O3; Photochemical destruction; Process analysis;

Characteristics of carbonaceous aerosol in the region of Beijing, Tianjin, and Hebei, China by Pusheng Zhao; Fan Dong; Yadong Yang; Di He; Xiujuan Zhao; Wenzong Zhang; Qing Yao; Huaiyu Liu (389-398).
More than 400 PM2.5 samples were collected at four urban sites in Beijing (BJ), Tianjin (TJ), Shijiazhuang (SJZ), and Chengde (CD), and also one site in Shangdianzi (SDZ), which was used as a regional background station, over four seasons from 2009 to 2010. The organic carbon (OC) and elemental carbon (EC) in each sample were analyzed. The average annual concentrations were 71.8–191.2 μg m−3 for PM2.5, 10.8–26.4 μg m−3 for OC, and 3.9–9.7 μg m−3 for EC at the five sites. OC and EC concentrations were lower in the spring and summer and much higher in the autumn and winter, mainly due to aerosol emissions from additional fuel combustion for heating. OC/EC ratios were lowest in the summer and highest in the winter at SDZ, BJ, TJ, and SJZ. These seasonal trends indicate that the characteristics of carbonaceous aerosol pollution were spatially similar and season-dependent in the plain area of Beijing, Tianjin, and Hebei (BTH). An EC tracer method was used to calculate the concentrations for secondary organic carbon (SOC); SOC concentrations were also higher in the autumn and winter and lowest during the summer at all five sites. A stable atmosphere and low temperatures, which were more frequent during the winter and autumn, facilitated the accumulation of air pollutants and accelerated the condensation or adsorption of volatile organic compounds in the BTH area. Over the past ten years (1999–2009), Beijing had observed a decrease in the EC concentrations during every season and a remarkable reduction in aerosol emissions from coal combustion for heating.► OC, EC, and OC/EC were spatially similar and season-dependent in the BTH area. ► OC and EC were higher in the autumn and winter due to more fuel combustion for heating. ► OC and EC in all four seasons have decreased in Beijing over the past ten years. ► SOC concentrations were also higher in the autumn and winter at five sites.
Keywords: Carbonaceous aerosol; Organic carbon; Elemental carbon; Secondary organic carbon;

Identifying and quantifying secondhand smoke in multiunit homes with tobacco smoke odor complaints by Philip J. Dacunto; Kai-Chung Cheng; Viviana Acevedo-Bolton; Neil E. Klepeis; James L. Repace; Wayne R. Ott; Lynn M. Hildemann (399-407).
Accurate identification and quantification of the secondhand tobacco smoke (SHS) that drifts between multiunit homes (MUHs) is essential for assessing resident exposure and health risk. We collected 24 gaseous and particle measurements over 6–9 day monitoring periods in five nonsmoking MUHs with reported SHS intrusion problems. Nicotine tracer sampling showed evidence of SHS intrusion in all five homes during the monitoring period; logistic regression and chemical mass balance (CMB) analysis enabled identification and quantification of some of the precise periods of SHS entry. Logistic regression models identified SHS in eight periods when residents complained of SHS odor, and CMB provided estimates of SHS magnitude in six of these eight periods. Both approaches properly identified or apportioned all six cooking periods used as no-SHS controls. Finally, both approaches enabled identification and/or apportionment of suspected SHS in five additional periods when residents did not report smelling smoke. The time resolution of this methodology goes beyond sampling methods involving single tracers (such as nicotine), enabling the precise identification of the magnitude and duration of SHS intrusion, which is essential for accurate assessment of human exposure.► We monitored 5 multiunit homes with secondhand smoke (SHS) odor complaints. ► We measured particle size, particle composition, and VOCs. ► Logistic regression models correctly identified SHS in 8 smoke odor periods. ► Chemical mass balance analysis produced estimates of SHS in 6 of the 8 periods. ► Identification and quantification of SHS at precise timescales is feasible.
Keywords: Multiunit dwellings; Chemical mass balance; Logistic regression; Nicotine; Source apportionment; Indoor emissions;

The Authors (Avnery et al., 2011a,b) estimated the relative yield losses of wheat crop in China in 2000 and 2030 to be 15%–20% and 25%–30%, respectively. And the relative yield losses of soybean crop in China in 2000 and 2030 to be 20%–25% and 30%–45%, respectively. These findings do not agree with the information that shows the relative yield losses of wheat crop should be greater than those of soybean crop in China. Additionally, do not agree with the findings of previous studies.
Keywords: Ozone; Wheat; Soybean; AOT40; Relative yield;

Corrigendum to “Daily and hourly sourcing of metallic and mineral dust in urban air contaminated by traffic and coal-burning emissions” [Atmos. Environ. 68 (2012), 33–44] by T. Moreno; A. Karanasiou; F. Amato; F. Lucarelli; S. Nava; G. Calzolai; M. Chiari; E. Coz; B. Artíñano; J. Lumbreras; R. Borge; E. Boldo; C. Linares; A. Alastuey; X. Querol; W. Gibbons (415).

Corrigendum to “Molecular marker characterization of the organic composition of submicron aerosols from Mediterranean urban and rural environments under contrasting meteorological conditions” [Atmos. Environ. 61 (2012) 482–489] by Barend L. van Drooge; Michael Cusack; Cristina Reche; Claudia Mohr; Andres Alastuey; Xavier Querol; Andre Prevot; Douglas A. Day; Jose L. Jimenez; Joan O. Grimalt (416).