Atmospheric Environment (v.38, #27)
List for forthcoming papers (I-II).
Editorial Board (i).
Emissions and accumulation of metals in the atmosphere due to crackers and sparkles during Diwali festival in India by U.C. Kulshrestha; T. Nageswara Rao; S. Azhaguvel; M.J. Kulshrestha (4421-4425).
In India, Diwali is known as one of the most famous festivals. On the occasion of this festival, people burn crackers and sparkles to express their happiness. The burning of these fireworks leads to metal pollution in air. In this study, metal concentrations in ambient air were observed to be very high as compared to background values on previous days. For some metals the concentrations were observed to be higher than reported at industrial sites. The order of concentration of metals on the day of festival was observed to be in the order—K>Al>Ba>Mg>Fe>Sr>Na>Ca>Cu>Mn>As>V>Ni>Bi. Interestingly, the concentrations of Ba, K, Al and Sr went up to 1091, 25, 18 and 15 times higher than the previous day of Diwali. This study indicated that burning of crackers and sparkles on Diwali is a very strong source of air pollution which contributes significantly high amount of metals in air.
Keywords: Air pollution; Metals; Fireworks; Festival; Emission;
Statistical comparison of observed and CMAQ modeled daily sulfate levels by Mikyoung Jun; Michael L Stein (4427-4436).
New statistical procedures to evaluate the Models-3/Community Multiscale Air Quality (CMAQ) using observed data are introduced. Certain space–time correlations are used to assess dynamic aspects of CMAQ and to compare the space–time structure of CMAQ to that of observations. Our analyses show that, overall, CMAQ matches the space–time correlation structure of observed sulfate concentrations well. Analyses on the space–time correlation of the difference of observations and CMAQ output show that CMAQ partially captures time lagged spatial variation of sulfate concentrations. Separable covariance functions are shown to provide a poor description of the observations.
Keywords: Air quality model; Model evaluation; Space–time process; Separable covariance function;
The role of atmospheric dispersion in the seasonal variation of PM1 and PM2.5 concentration and composition in the urban area of Milan (Italy) by R. Vecchi; G. Marcazzan; G. Valli; M. Ceriani; C. Antoniazzi (4437-4446).
The seasonal variation of PM1 and PM2.5 mass concentration and composition has been investigated in the great urban area of Milan. PM samplings were carried out 3 times a week during the year 2002. Mass and elemental concentrations were measured in all samples and in a limited number of filters also the elemental and organic carbon contribution (EC and OC) was determined.In the urban area of Milan, PM2.5 comprises about 60% and 70% of the PM1 mass in summer and in winter, respectively. Among the measured PM components carbon compounds and sulphates are by far the major contributors and a significant contribution likely due to nitrates (not measured) should also be considered. PM1 and PM2.5 concentration and composition show a strong seasonal behaviour, which was studied in relation to atmospheric dispersion conditions.Our approach is based on the use of Radon concentration as a natural tracer of differences in the average mixing layer height during the year. The application of a suitable “Radon index” allows the normalisation of PM mass and elemental data to account for the seasonal effect due to differences in atmospheric dispersion conditions.
Keywords: PM1; PM2.5; Elemental composition; Radon;
Spatial and seasonal variations of atmospheric organic carbon and elemental carbon in Pearl River Delta Region, China by J.J Cao; S.C Lee; K.F Ho; S.C Zou; Kochy Fung; Y Li; John G Watson; Judith C Chow (4447-4456).
The concentrations of organic carbon (OC) and elemental carbon (EC) in atmospheric particles were investigated at eight sites in four cities (Hong Kong, Guangzhou, Shenzhen and Zhuhai) of the Pearl River Delta Region (PRDR), China, during winter and summer 2002. The comparison of summer and winter results was made in order to investigate spatial and seasonal variations. PM2.5 and PM10 samples were collected on pre-fired quartz filters with mini-volume samplers and analyzed by the thermal optical reflectance (TOR) method following the Interagency Monitoring of PROtected Visual Environments (IMPROVE) protocol. During summer, the average OC and EC concentrations in PM2.5 were 9.2 and 4.1 μg m–3, while those in PM10 were 12.3 and 5.2 μg m–3. Carbonaceous aerosol accounted for 38.0% of the PM2.5 and 32.9% of the PM10. The daily average OC, EC, PM2.5 and PM10 concentrations in PRDR were higher in winter than in summer. The average OC/EC ratio was 2.5 for PM2.5 and PM10, suggesting the presence of secondary organic aerosols. The estimated secondary organic carbons in PM2.5 and PM10 were 4.1 and 5.6 μg m–3, respectively. The OC and EC were found to be correlated in winter (correlation coefficient r=0.82) and summer (r=0.64), which implied that motor vehicle sources contributed to the ambient carbonaceous particles. The distribution of eight carbon fractions in OC and EC at eight sites was first reported in ambient samples in Asia, which also indicated that motor vehicle exhaust was the dominant contributor to carbonaceous particles.
Keywords: Organic carbon; Elemental carbon; Urban aerosol; Pearl River Delta Region;
Investigation of the effects of acid rain on the deterioration of cement concrete using accelerated tests established in laboratory by Shaodong Xie; Li Qi; Ding Zhou (4457-4466).
Deterioration of cement concrete specimens caused by simulated acid rain was investigated by laboratory tests. Before and after cement concrete specimens were exposed to simulated acid rain, the neutralized depth, the compressive strength and the chemical compositions in the hardened cement paste were measured. The mineralogical composition of the concrete specimens was analyzed with XRD. The results lead to the following conclusions: the neutralized depth of the concrete specimens of all experiments can be described as a power function of exposure duration, CaO loss and the reduction rate of strength increased with H+ and decreased with SO4 2− concentration in simulated acid rain. The original mineral compounds such as [Na K]AlSi3O8 and [Ca Na][SiAl]4O8 in the hardened cement paste are converted to CaSO4·2H2O, CaAl2Si2O8 and Ca3Al6O12·CaSO4. And these are larger in volume so that the reaction with SO4 2− ions result in volume expansion and strength decrease. The reduction rate of strength has a binary linear relation to the CaO loss rate and the ratio of SO3 content to CaO content in the hardened cement paste. So the deterioration of acid rain on the concrete specimen is caused by both H+ dissolution and SO4 2− expansion.
Keywords: Acid rain; Cement concrete; Corrosion; Deterioration; Accelerated test;
Direct radiative forcing due to anthropogenic aerosols in East Asia during April 2001 by Lim-Seok Chang; Soon-Ung Park (4467-4482).
An aerosol dynamic model including such processes of nucleation, condensation/evaporation, coagulation, sedimentation, hygroscopic growth and dry and wet deposition coupled with the gas-phase chemistry of the California Institute of Technology model and the aqueous-phase chemistry of the Regional Acid Deposition Model together with meteorological outputs of the MM5 model in a grid of 60×60 km2 has been used to estimate anthropogenic aerosols in East Asia (95–145E, 20–50N) for the period of 2–30 April 2001 in the ACE-Asia experimental period. During this period an Asian dust event has been observed from 10 to 13 and 24–26 April in the Korean peninsula. The estimated anthropogenic aerosols excluding the Asian dust are implemented to estimate radiative forcing at the surface, at the top of atmosphere (TOA) and atmospheric aerosol absorption in East Asia using the National Center for Atmospheric Research column radiation model of the community climate model. The results indicate that the area averaged column integrated anthropogenic aerosol concentration in East Asia is estimated to be about 20 mg m−2, of which 46%, 29%, 20%, 4% and 1% are contributed by mixed type, inorganic (IOC), sea salt, organic carbon and black carbon aerosol, respectively. The daytime area mean direct shortwave radiative forcing at the surface is found to be about −5.9 W m−2, of which IOC and the mixed type aerosol contribute about 95% whereas that at TOA is about −4.1 W m−2, of which the IOC and the mixed type aerosol contribute more than 90%. Consequently the area mean atmospheric absorption due to anthropogenic aerosol layer in East Asia is about 1.8 W m−2. The result clearly confirms the existence of a cooling effect (negative forcing) due to the direct effect of anthropogenic aerosols at the surface and TOA in East Asia. However, the atmosphere of the troposphere above the ground is slightly heated due to absorbing aerosol layers that are composed of black carbon and the mixed type aerosol.
Keywords: ACE-Asia; Aerosol process; Aerosol type; Column radiation model; East Asia;
Short-term variation in ambient concentrations and gas/particle partitioning of organochlorine pesticides in Izmir, Turkey by Aysun Sofuoglu; Eylem Cetin; Sevde Seza Bozacioglu; Gaye Devrim Sener; Mustafa Odabasi (4483-4493).
Twenty successive daytime and nighttime air samples were collected and analyzed for 23 currently used and/banned organochlorine pesticides (OCPs) between 14 and 23 May 2003 in Izmir, Turkey. Average individual OCP concentrations ranged from 5±4 pg m−3 (p,p′-dichlorodiphenyldichloroethane) to 391±306 pg m−3 (chlorpyrifos) and they were within the ranges previously measured at different sites.Most of the OCPs did not exhibit strong diurnal cycling. The temperature dependence of gas-phase atmospheric concentrations of OCPs investigated using Clausius–Clapeyron plots was statistically significant for β-HCH and endosulfan sulfate (p<0.1) and was not significant for other compounds (0–21% of the variability in their gas-phase concentrations). In addition to temperature, the effect of wind speed and direction was also investigated using multiple linear regression analysis and these three parameters together explained the 2% (aldrin) to 72% (endosulfan II) of the variability in gas-phase OCP concentrations. Results of the multiple regression analysis indicated that wind speed was a statistically significant factor for most of the OCPs and wind direction was important for some compounds. The temperature-dependent diurnal cycling of most OCPs was probably masked by the higher wind speeds observed during daytime periods with high temperatures, different source sectors and ongoing sources. The lack of correlation for heptachlor, aldrin, p,p′-dichlorodiphenyldichloroethylene (p-p′-DDE), and p,p′-dichlorodiphenyltrichloroethane (p-p′-DDT) with temperature, wind speed and direction suggested that their concentrations were affected by long-range transport.The partitioning of OCPs between particle and gas phases was investigated and compared to K OA (octanol/air partition coefficient) absorption model. The overall agreement between experimental and modeled log K p (gas/particle partition coefficient) values was good (p<0.01, slope=0.94). Prediction of absorption model for particulate percentages was excellent for β-HCH, endosulfan I, and p-p′-DDT. However, the model underpredicted the particulate percentages for α,γ-HCHs, chlorpyrifos, and dieldrin, and overpredicted those for p-p′-DDE.
Keywords: Organochlorine pesticides (OCPs); Gas/particle partitioning; Temperature dependence;
MTBE, methane, ethylene and regulated exhaust emissions from vehicles with deactivated catalytic converters by S.G. Poulopoulos; C.J. Philippopoulos (4495-4500).
In the present work, the effect of the gradual deactivation of a three-way catalytic converter on the exhaust emissions was studied. The exhaust gases were analyzed for CO, HC (i.e. total unburned organic compounds), MTBE, methane and ethylene, before and after their catalytic treatment, in a wide range of engine operating conditions. The thermal aging of the catalytic converter resulted in an increase in the required time for the start of its operation and loss of its auto thermal operation. The catalytic efficiency was significantly decreased after each thermal aging step, especially at idle conditions. As a result, CO and especially HC emissions were increased, whereas ethylene and MTBE emissions were multiplied by a factor of 6–7 at 3.81 hp, in the case of the deactivated catalyst.
Keywords: Thermal aging; Deactivation; Automotive catalyst;
Identifying the impact of large urban airports on local air quality by nonparametric regression by K.N Yu; Y.P Cheung; T Cheung; Ronald C Henry (4501-4507).
Emissions of air pollutants from aircraft in large urban areas are a health concern to nearby residents. This study examined hourly concentrations of CO, NO x , SO2, and respirable suspended particles (RSP) taken in the vicinity of Hong Kong International Airport (HKIA) and Los Angeles International Airport (LAX). The LAX data cover the period August 1997 through March 1998 and the HKIA all of 2000 and 2001. The average concentration as a function of wind speed and direction was estimated by nonparametric regression. The error variance of the nonparametric regression results was also estimated. The results show that SO2 can be used to identify wind speeds and directions associated with emissions from aircraft. Using this assumption and the nonparametric regression plots for the other pollutants one can identify the impact of aircraft on local air quality. At LAX, CO and NO x are dominated by emissions from ground vehicles going in and out of the airport. However, near HKIA, aircraft are an important contributor to CO and RSP. At both sites, nonparametric regression identified other, smaller sources as well.
Keywords: Air pollution; Airports; Hong Kong; Los Angeles; Receptor modeling; Statistics; Data analysis; Nonparametric regression;
A GIS based decision support system for estimation, visualization and analysis of air pollution for large Turkish cities by Tolga Elbir (4509-4517).
A decision support system has been developed to support local authorities in air quality management for big Turkish cities. The system is based on CALPUFF dispersion model, digital maps and related databases to estimate the emissions and spatial distribution of air pollutants. It applies a geographical information system. The system estimates ambient air pollution levels at high temporal and spatial resolutions. The system enables mapping of emissions and air quality levels. Mapping and scenario results can be compared with air quality limits. Impact assessment of air pollution abatement measures can also be carried out.
Keywords: Urban air quality management; Decision support system; Air quality modeling; Emission inventory; Geographic information system;
Properties of the size-resolved and individual cloud droplets collected in western Japan during the Asian dust storm event by Chang-Jin Ma; Susumu Tohno; Mikio Kasahara; Shinjiro Hayakawa (4519-4529).
With the point of view of the removal mechanism of Asian dust storm particles, in order to study the physiochemical properties of clouds a field campaign was conducted in western Japan during the Asian dust storm event. The polymeric water absorbent film and collodion film replication techniques were employed in the measurements of size-fractionated precipitation cloud and individual cloud droplets, respectively. In addition, to investigate the source profiles of the elements retained in cloud samples, the original desert sand was collected. Particle-induced X-ray emission was applied for the elemental analysis of size-resolved cloud droplets and desert sand. Also for the quantification analysis of the ultra trace elements in residual particles in individual cloud droplets, the X-ray microprobe system equipped at Super Photon ring-8 GeV (SPring-8) BL-37XU was newly applied. Soil derived components like Si, Ca, and Fe show higher mass concentrations in small droplets (<6.4 μm) than in large droplets (>6.4 μm), while S and Cl dominate at droplet size larger than 20 μm. Three cloud samples have liquid water content ranging from 0.04 to 0.11 g m−3. The number size distribution of droplets collected at cloud base is monomodal with the maximum level around 15 μm. The size distribution of cloud droplets is widespread (up to 60 μm). The droplet residues mainly consisting of crustal components were successively reconstructed as elemental maps by the X-ray fluorescence (XRF) microprobe analytical technique. From these XRF elemental maps, it can be understood that crustal components are significantly distributed on and/or in the residual particles in individual cloud droplets. The plotting of enrichment factors calculated from the elemental composition of original desert sand in China not only indicates the good correlationship between elemental masses in residual particles of cloud base droplets and those of precipitation cloud, but also classify elements into soil origin and non-soil origin. Mineral components were identified as the main components of dry residual particles in cloud droplets. These soil-origin elements account for up to 68% of the total elemental mass.
Keywords: Individual cloud droplets; Polymeric water absorbent film; Asian dust storm; XRF microprobe analysis; Elemental map;
Major component composition of PM10 and PM2.5 from roadside and urban background sites by Roy M. Harrison; Alan M. Jones; Royston G. Lawrence (4531-4538).
Using dichotomous Partisol samplers, airborne particulate matter has been collected and analysed as PM2.5 and PM10. The instruments were deployed at four sets of paired roadside and urban background locations, three in London and one in Birmingham (UK) and the sampling protocols aimed to give equal weight to all seasons of the year. In addition to determination of sample mass, concentrations have been determined for major chemical components as follows: sulphate, nitrate, chloride, organic carbon, elemental carbon, iron and calcium. The measured concentrations have been converted to equivalent quantities of ammonium sulphate, ammonium nitrate (in PM2.5), sodium nitrate (in PM2.5–10), sodium chloride, elemental carbon, carbon compounds, gypsum and iron-rich dusts. The mass of strongly bound water has also been calculated following the mass closure methodology of Harrison et al. (Atmos. Environ. 37 (2003) 4927). Examination of the difference between roadside (mean 34.7 μg m−3 PM10) and corresponding urban background (mean 23.2 μg m−3 PM10) samples indicates average mass increments of 11.5 μg m−3 of PM10 and 8.0 μg m−3 of PM2.5 for the four site pairs, and that the roadside particle increment is comprised very largely of elemental carbon, organic compounds and iron-rich dusts. The major component composition lies somewhere between that reported as typical of the eastern and western US. A comparison with PM2.5 and PM15 sampled in Leeds (UK) in 1982 shows a decline in all major constituents except mineral dusts (PM2.5 only). In a comparison of data for days with PM10 above the EU 24-h Limit Value of 50 μg m−3 with data from all days, the component showing the greatest ratio between high pollution days and all days is fine particle nitrate.
Keywords: Particulate matter; PM10; PM2.5; Chemical composition; Roadside; Urban background;
Nocturnal trans-alpine transport of ozone and its effects on air quality on the Swiss Plateau by M Steinbacher; S Henne; J Dommen; P Wiesen; A.S.H Prevot (4539-4550).
Trace gas measurements in the Leventina valley in southern Switzerland were performed in August and September 2001. Highest concentrations of secondary air pollutants (ozone and formaldehyde) were measured at an elevated site during nights with southerly winds. The analysis of ozone data at an elevated site in southern Switzerland from 1991 to 1998 corroborated that enhanced pollutant levels originating from the residual layer of the Po Basin led to an increase of ozone during spring and summer nocturnal southerly advection. Average differences of up to more than 20 ppb were found when comparing the nighttime ozone mixing ratios during persistent southerly and northerly advection. The impact of the nocturnal trans-Alpine transport on the residual layer north of the Alps could be shown by means of a case study and an analysis of a perennial time series of ozone for an elevated station north of the Alpine crest. The afternoon spring and summer ozone concentrations in the boundary layer north of the Alps were on average 2.5 ppb higher after persistent southerly advection and fair weather conditions in the previous night. This concentration increase due to nocturnal trans-Alpine transport was estimated to be responsible for additional 5% of hours with ozone levels above the Swiss national air quality standard.
Keywords: Tropospheric ozone; Horizontal transport; Residual layer; Alps; Alpine meteorology;
Source contributions to ambient VOCs and CO at a rural site in eastern China by H Guo; T Wang; I.J Simpson; D.R Blake; X.M Yu; Y.H Kwok; Y.S Li (4551-4560).
Ambient data on volatile organic compounds (VOCs) and carbon monoxide (CO) obtained at a rural site in eastern China are analyzed to investigate the nature of emission sources and their relative contributions to ambient concentrations. A principal component analysis (PCA) showed that vehicle emissions and biofuel burning, biomass burning and industrial emissions were the major sources of VOCs and CO at the rural site. The source apportionments were then evaluated using an absolute principal component scores (APCS) technique combined with multiple linear regressions. The results indicated that 71%±5% (average±standard error) of the total VOC emissions were attributed to a combination of vehicle emissions and biofuel burning, and 7%±3% to gasoline evaporation and solvent emissions. Both biomass burning and industrial emissions contributed to 11%±1% and 11%±0.03% of the total VOC emissions, respectively. In addition, vehicle emissions and biomass and biofuel burning accounted for 96%±6% of the total CO emissions at the rural site, of which the biomass burning was responsible for 18%±3%. The results based on PCA/APCS are generally consistent with those from the emission inventory, although a larger relative contribution to CO from biomass burning is indicated from our analysis.
Keywords: Receptor model; PCA/APCS; Source apportionments; Biomass and biofuel burning; Rural china;
Detection of very large ions in aircraft gas turbine engine combustor exhaust: charged small soot particles? by S Wilhelm; H Haverkamp; A Sorokin; F Arnold (4561-4569).
Small electrically charged soot particles (CSP) present in the exhaust of a jet aircraft engine combustor have been detected by a Large Ion Mass Spectrometer and quantitatively measured by an Ion Mobility Analyzer. The size and concentration measurements which took place at an aircraft gas-turbine engine combustor test-rig at the ground covered different combustor conditions (fuel flow=FF, fuel sulphur content=FSC). At the high-pressure turbine stage of the engine, CSP-diameters were mostly around 6 nm and CSP-concentrations reached up to 4.8×107 cm−3 (positive and negative) corresponding to a CSP-emission index E CSP=2.5×1015 CSP kg−1 fuel burnt. The E CSP increased with FF but did not increase with FSC. The latter indicates that sulphur was not a major component of the large ions. Possible CSP-sources and CSP-sinks as well as CSP-roles are discussed.
Keywords: Aircraft engine; Chemiions emission; Charged soot particles;
Aerosol properties in a Chinese semiarid region by Xia Xiangao; Chen Hongbin; Wang Pucai (4571-4581).
Aerosol optical properties and atmospheric water vapor content for 1999–2000 were obtained from ground-based solar radiometer measurements in Dunhuang, China. Seasonal changes of aerosol optical depth (AOD) and Angstrom wavelength parameter (ALPHA) were observed. Large values of AOD (at 500 nm) greater than 1.0 combined with low values of ALPHA less than 0.2 were mainly observed in spring and summer, which is consistent with the seasonal dust production from Gobi and Taklamaken deserts. The maximum monthly average of AOD was around 0.37 and occurred in the April of 1999, which was more than three times larger than the minimum monthly average in the November of 2000 (around 0.115). Thirty-three percent and 49% of observations of AOD in autumn and winter was larger than 0.2, respectively, whereas in spring, the percentage was approximately 63%. There was a large spread in ALPHAs in all seasons when AODs were less than 0.2. With the increase of AOD, ALPHAs decreased rapidly and were around zero finally. The large spread of ALPHA for low AODs and the domination of low turbidity in Dunhuang (nearly half of AODs less than 0.2) resulted in the negligible seasonal change of ALPHA. The domination of coarse particles over fine particles was also shown in aerosol size distribution retrievals, with the volume concentration ratio of coarse to fine particles being nearly 30. The volume mean radii and standard deviation of size distribution showed an insignificant correlation with AOD based on the analysis of all available retrievals, illustrating that it is suitable to use a fixed size model in the analysis of the dust climate forcing. During the dust outbreak episode, a rapid increase of AOD and a decrease of ALPHA were observed, ALPHA being usually less than 0.2 and even negative occasionally. The interesting result was that the volume mean radii of size distribution during the dust outbreak episode increased remarkably with the dust loading, which indicated that a dynamic size model should be used in the simulation of dust effects on meso-scale weather system in the semiarid region. The distinct seasonal change of water vapor content was observed, with high water vapor contents occurred in summer. The influence of water vapor on aerosol properties was absent due to the low humidification capability of dust aerosols and the different seasonal variation of aerosol properties and water vapor content.
Keywords: Dust aerosol optical depth; Angstrom wavelength parameter; Size distribution; Dunhuang;
Measurements of CH4 and CO during ship cruises in the South Atlantic by P.C Alvalá; C Boian; V.W.J.H Kirchhoff (4583-4588).
Shipboard air grab samplings were made in November 2000, and in March 2001, to study the distribution of the atmospheric CH4 and CO in the South Atlantic region. The observations were performed in two campaigns during the cruise between Rio de Janeiro (22°54′S, 43°10′W) and the Brazilian Comandante Ferraz Antarctic Station (62°05′S, 58°24′W), and the cruise back to Rio de Janeiro. The sampling was performed using two canisters filled in a sequential way for each sampling day. Most of the average mixing ratios of CH4 for November 2000 were slightly lower than the expected values for this region, with an average of 1707.3±8.4 ppbv, without a clear latitudinal tendency. The mixing ratios for CO presented averages very near to the expected values for that region, with an average of 52.7±6.5 ppbv, showing a latitudinal variation as observed by other studies. For March 2001, the CH4 average mixing ratios showed a somewhat lower latitudinal spread than that observed in November 2000, with two sampling points showing lower mixing ratios in comparison with the other. However, the average of 1688.8±7.3 ppbv is very near that observed at the same latitude by other studies. The CO average mixing ratios presented a very low dispersion, with an average of 41.1±7.6 ppbv, with a very clear latitudinal variation. Both trace gases showed a seasonal difference between the two periods, which was very clear in the ratio CH4/CO. To determine the origin of sampled air masses, back trajectories for 48 h were calculated for isentropic surfaces of 1.5 km altitude or lower. With the exception of some trajectories between the latitudes of 30°S and 34°S, which were originated in the continent, most of them had origin from west direction, beginning in the Pacific Ocean.
Keywords: Methane; Carbon monoxide; Latitudinal variation; Marine boundary layer;
Corrections to a description of turbulence in a trafficked street canyon in Manchester by I.D Longley (4589-4592).
A paper previously published in Atmospheric Environment (Longley et al. (Atmos. Environ 38 (2004) 69) contained a model describing turbulence data measured in the field. Subsequent re-analysis of the data has uncovered fundamental and irreparable errors in the raw data from one anemometer. This dataset covered measurements by a mobile anemometer at a height of 2 m above a road surface within a street canyon. Some key conclusions concerning the influence of traffic upon turbulence were dependent upon this dataset and are no longer valid. New data has been captured from the original street canyon to correct and replace this erroneous data. This new data indicates that the weak positive gradient in turbulent intensity higher in the canyon described in the original paper is consistent down to 2 m and that the sharp enhancement at this height originally reported was not observed in the replacement data.
Keywords: Street canyon; Traffic-induced turbulence; Turbulent intensity;
PM2.5 and associated ionic component concentrations inside the archaeological museum of Thessaloniki, N. Greece by Th. Mouratidou; C. Samara (4593-4598).
PM2.5 and its associated ionic component concentrations (Cl−, Br−, F−, NO3 −, NO2 −, SO4 2−, HCOO−, CH3COO−, H2PO4 −, Na+, K+, NH4 +, Ca2+, Mg2+) were determined in the Archaeological Museum of Thessaloniki (AMT), in Northern Greece, where sculptures and other antiquities dated from the Archaic, Classical, Hellenistic and Roman times are displayed. Indoor and outdoor PM2.5 samplings were concurrently carried out over a 3-month period. Both sites showed similar temporal variations with indoor PM2.5 concentrations exceeding outdoor levels. Resuspension of soil dust particles introduced by visitors and restoration works carried out during sampling campaign were concluded as being major indoor sources for fine particles and associated calcium. Sulfate was found to be the dominant ion in indoor aerosol originating from external penetration rather than indoor sources. Increased indoor acidity was also observed resulting from the potential presence of partially neutralized ammonium sulfate.
Keywords: Fine particulate matter; Indoor air; Ionic constituents; Museum;
New Directions: Infrared measurements of atmospheric pollution from space by Cathy Clerbaux; John Gille; David Edwards (4599-4601).
Erratum to “Annual and seasonal trends of wet deposition in Japan”[Atmospheric Environment 38 (22) (2004) 3543–3556] by Sinya Seto; Hiroshi Hara; Manabu Sato; Izumi Noguchi; Yutaka Tonooka (4603-4605).