Atmospheric Environment (v.45, #40)

Effects of air pollution on children’s pulmonary health by Afrim Tabaku; Gazmend Bejtja; Silvana Bala; Ervin Toci; Jerina Resuli (7540-7545).
Many reports regarding the effects of air pollution on children’s respiratory health have appeared in the scientific literature. Some investigators found increases in persistent cough and phlegm, bronchitis, and early respiratory infections in communities with poor air quality. The purpose of this survey was to compare the pulmonary function of children living in urban area of Tirana city with children living in suburban area of the city.This survey is carried out during 2004–2005 period on 238 children living in urban area and in 72 children living in suburban area, measuring dynamic pulmonary function. A questionnaire was used to collect data on sex, current respiratory symptoms, allergy diagnosed by the physician, parent education and smoking habit of parents, presence of animals, synthetic carpets and moulds in their houses. The selection of schools, and children included in this survey was done by randomized method. Also, we have measured and classic air pollutants.Comparing the results of values of pulmonary function of two groups of children, we have shown that differences were significant (p 0.001), whereas comparing symptoms were for cough (p 0.011) and for phlegm (p 0.032). The level of particulate matter (PM10) and total suspended matter (TSP) were over the recommended limit values, whereas the levels of other pollutants have resulted within recommended levels of World Health Organization (WHO)The results of this survey suggest that air pollution is associated with respiratory health of children causing a slight decrease in values of pulmonary function in children of urban area compared with those of suburban area.
Keywords: Air pollution; Children; Particulate matter; Total suspended matter; Pulmonary function; Respiratory disease;

In vitro immunotoxic and genotoxic activities of particles emitted from two different small-scale wood combustion appliances by Maija Tapanainen; Pasi I. Jalava; Jorma Mäki-Paakkanen; Pasi Hakulinen; Mikko S. Happo; Heikki Lamberg; Jarno Ruusunen; Jarkko Tissari; Kati Nuutinen; Pasi Yli-Pirilä; Risto Hillamo; Raimo O. Salonen; Jorma Jokiniemi; Maija-Riitta Hirvonen (7546-7554).
Residential wood combustion appliances emit large quantities of fine particles which are suspected to cause a substantial health burden worldwide. Wood combustion particles contain several potential health-damaging metals and carbon compounds such as polycyclic aromatic hydrocarbons (PAH), which may determine the toxic properties of the emitted particles. The aim of the present study was to characterize in vitro immunotoxicological and chemical properties of PM1 (D p ≤ 1 μm) emitted from a pellet boiler and a conventional masonry heater. Mouse RAW264.7 macrophages were exposed for 24 h to different doses of the emission particles. Cytotoxicity, production of the proinflammatory cytokine TNF-α and the chemokine MIP-2, apoptosis and phases of the cell cycle as well as genotoxic activity were measured after the exposure. The type of wood combustion appliance had a significant effect on emissions and chemical composition of the particles. All the studied PM1 samples induced cytotoxic, genotoxic and inflammatory responses in a dose-dependent manner. The particles emitted from the conventional masonry heater were 3-fold more potent inducers of programmed cell death and DNA damage than those emitted from the pellet boiler. Furthermore, the particulate samples that induced extensive DNA damage contained also large amounts of PAH compounds. Instead, significant differences between the studied appliances were not detected in measurements of inflammatory mediators, although the chemical composition of the combustion particles differed considerably from each other. In conclusion, the present results show that appliances representing different combustion technology have remarkable effects on physicochemical and associated toxicological and properties of wood combustion particles. The present data indicate that the particles emitted from incomplete combustion are toxicologically more potent than those emitted from more complete combustion processes.► Toxicological and chemical properties of particles from small-scale wood combustion. ► The particles from the masonry heater induced more apoptosis and DNA damage in vitro. ► The chemical composition of the combustion particles was different. ► The toxicological responses might associated with PAHs and other organics. ► The particles emitted from incomplete combustion are toxicologically more potent.
Keywords: Small-scale wood combustion; Particulate matter; Cytotoxicity; Genotoxicity; Inflammation; Chemical composition;

Inhalation of ambient particulate matter causes morbidity and mortality in humans. One hypothesized mechanism of toxicity is the particle-induced formation of reactive oxygen species (ROS) – including the highly damaging hydroxyl radical (•OH) – followed by inflammation and a variety of diseases. While past studies have found correlations between ROS formation and a variety of metals, there are no quantitative measurements of •OH formation from transition metals at concentrations relevant to 24-hour ambient particulate exposure. This research reports specific and quantitative measurements of •OH formation from 10 individual transition metals (and several mixtures) in a cell-free surrogate lung fluid (SLF) with four antioxidants: ascorbate, citrate, glutathione, and uric acid. We find that Fe and Cu can produce •OH under all antioxidant conditions as long as ascorbate is present and that mixtures of the two metals synergistically increase •OH production. Manganese and vanadium can also produce •OH under some conditions, but given that their ambient levels are typically very low, these metals are not likely to chemically produce significant levels of •OH in the lung fluid. Cobalt, chromium, nickel, zinc, lead, and cadmium do not produce •OH under any of our experimental conditions. The antioxidant composition of our SLF significantly affects •OH production from Fe and Cu: ascorbate is required for •OH formation, citrate increases •OH production from Fe, and both citrate and glutathione suppress •OH production from Cu. MINTEQ ligand speciation modeling indicates that citrate and glutathione affect •OH production by changing metal speciation, altering the reactivity of the metals. In the most realistic SLF (i.e., with all four antioxidants), Fe generates approximately six times more •OH than does the equivalent amount of Cu. Since levels of soluble Fe in PM are typically higher than those of Cu, our results suggest that Fe dominates the chemical generation of •OH from deposited particles in the lungs.►Of 10 metals tested, Fe and Cu produce the most •OH in a surrogate lung fluid. ►Antioxidant composition significantly affects •OH production from metals. ►Glutathione and citrate alter •OH production by changing metal speciation. ►Mixtures of Fe and Cu synergistically produce •OH
Keywords: Reactive oxygen species (ROS); Particulate matter (PM); Oxidative stress; Iron; Copper; Fenton reaction;

Hourly concentrations of non-methane hydrocarbons (NMHCs) were collected at a background monitoring site between April of 2004 and March of 2005 and at suburban and urban sites between March and December of 2006. The sources of NMHCs were identified and associated health risks through the inhalation pathway were evaluated. Positive matrix factorization (PMF) results showed that solvent sources account for the largest portion of the total NMHCs at suburban and urban areas in South Korea, and the risk assessment combined with the PMF results indicated that risk-weighted contributions of solvent sources were enhanced compared to the absolute contribution (from 52% to 68% in suburban areas and from 47% to 80% in urban areas). Carcinogenic risk due to benzene exposure exceeded the one-in-a-million (i.e., 10−6) cancer benchmark at all three study sites, and the fractions of the population with greater than the benchmark level were 87%, 99%, and 98% in the background, suburban, and urban sites, respectively. Common benzene sources of three study sites were predicted to be Shandong in China based on the 120 h potential source contribution function (PSCF) analysis.To prioritize management options for NMHC sources, risk term may give more meaningful information than amount term. This study suggests that controlling solvent sources would be better option for the mitigation of non-carcinogenic health risk from airborne NMHCs. In addition, the identification of benzene sources using PSCF can be used to assist policymakers in developing regional measures to reduce benzene.► Solvent use was the largest source of ambient NMHCs at suburban and urban areas. ► Risk-weighted portion of solvent source was greater than their absolute portion. ► Carcinogenic risk due to benzene exceeded 10−6 benchmark at all three study sites. ► Common benzene sources were predicted to be Shandong in China based on 120 h PSCF
Keywords: Benzene; Non-methane hydrocarbon (NMHC); Positive matrix factorization (PMF); Potential source contribution function (PSCF); Risk assessment;

Ultrafine particle concentrations and exposures in four high-rise Beijing apartments by Nasim A. Mullen; Cong Liu; Yinping Zhang; Shuxiao Wang; William W. Nazaroff (7574-7582).
Ultrafine particle (UFP) exposures have the potential to elicit adverse health effects. People spend most of their time within their place of residence. Little information is available on UFP levels in homes in mainland China. To contribute new data to this important topic, we made time-series measurements of particle number (PN) concentrations and resident activities inside four apartments in high-rise buildings in Beijing during June to August 2009. Indoor PN concentrations at the four sites, averaged over the few-day duration of monitoring at each site, spanned an order of magnitude, from 2800 to 29,100 cm−3. This wide range resulted from differences among apartments in three main factors: (1) the frequency of indoor source events, including cooking activities and intrusion of cooking exhaust from neighboring apartments; (2) the extent of natural ventilation via open windows; and (3) the extent of active air filtration. Daily-integrated PN exposure of the thirteen residents, while in their apartments, ranged from 45,000 to 494,000 cm−3 h/d. For two sites at which outdoor PN concentrations were also measured, the percentage of daily-integrated residential exposure attributable to particles of outdoor origin was 58% for the residents of one site and 81% for residents of the other.
Keywords: Ultrafine; Particle number; China; Exposure; Apartments;

Residential indoor and outdoor ultrafine particles in Windsor, Ontario by J. Kearney; L. Wallace; M. MacNeill; X. Xu; K. VanRyswyk; H. You; R. Kulka; A.J. Wheeler (7583-7593).
UFPs in the 20–100 nm size range were measured for 10 mins every hour for 5 consecutive days in 45 homes of nonsmoking adults in summer 2005 and in 49 homes of asthmatic children in summer and winter 2006. Median hourly outdoor levels across all measurements were 10,800, 12,000 and 6300 cm−3 and median indoor levels were 2700, 3730 and 2580 cm−3 in summer 2005, winter 2006 and summer 2006, respectively. Outdoor levels generally exceeded indoor levels but indoor concentrations were higher around 5–7pm, suggesting a strong influence of cooking. Daily and weekly infiltration factors were estimated for each home using three methods. Weekly infiltration factors (F inf’s) based on a censored indoor/outdoor ratio method varied widely across homes; median F inf’s across homes were 0.16 (summer 2005), 0.21 (winter 2006) and 0.26 (summer 2006). Large indoor peaks and low infiltration of ambient PM resulted in the indoor sources generally contributing more than infiltrated ambient UFPs to indoor concentrations. Median estimates of the percentage of indoor-generated contribution to total indoor levels were 58% (summer 2005), 65% (winter 2006) and 69% (summer 2006). The proportion of homes having more than half of their indoor concentrations provided by indoor sources was 66% (summer 2005), 67% (winter 2006) and 79% (summer 2006). Median deposition rates ranged from 0.61–0.79 h−1 across the 3 sampling sessions. Spatial variability was higher for outdoor UFPs than concurrently measured PM2.5. The median correlations of hourly averaged outdoor UFPs between pairs of homes were moderate in the three sampling sessions (0.56–0.65), but were considerably lower than corresponding PM2.5 correlations. The wide range of infiltration factors across homes as well as the spatial variability and moderate between- home correlations of outdoor UFPs could cause measurement error in epidemiology studies that use central site UFP measurements as a surrogate for personal exposure to ambient UFPs.► Residential indoor and outdoor ultrafine particles were measured in Windsor, Ontario. ► Outdoor UFPs were more spatially variable than concurrently measured PM2.5. ► Outdoor levels generally exceeded indoor levels but indoor peaks were larger. ► Infiltration rates were variable across homes; seasonal medians ranged from 16 to 26%. ► Median deposition rates ranged from 0.6 to 0.8 h−1 across the 3 sampling sessions.
Keywords: Ultrafine particles; Infiltration factor; Indoor concentration; Outdoor concentration; Ambient concentration; Deposition rate; Spatial variability; Temporal variability;

Children exposure to atmospheric particles in indoor of Lisbon primary schools by Susana Marta Almeida; Nuno Canha; Ana Silva; Maria do Carmo Freitas; Priscilla Pegas; Célia Alves; Margarita Evtyugina; Casimiro Adrião Pio (7594-7599).
Evidence continues to emerge showing that poor Indoor Air Quality (IAQ) can cause illness requiring absence from schools, and can cause acute health symptoms that decrease students’ performance. Since children spend on average 7–11 h per weekday at school, the IAQ in classrooms is expected to play a key role in the assessment of the effects of their personal exposure to air pollution. Within this context the present study was conducted in order to fulfill three primary objectives 1) to measure the levels and the element composition of PM2.5 and PM2.5–10, in three primary schools placed in Lisbon, in order to assess the children exposure to these pollutants; 2) to study the relationship between indoor and outdoor atmospheric particles concentrations and 3) to investigate the sources of high aerosols concentrations in classrooms. In the studied classrooms, the concentrations of coarse particles significantly exceeded the ambient levels. Element concentrations suggested that the physical activity of students highly contributed to the re-suspension of sedimented particles. The high levels of CO2 indicated that in these schools the ventilation was inadequate. This fact contributed to the establishment of poor IAQ.► In classrooms, PM2.5–10 concentrations significantly exceed the ambient concentrations. ► Physical activity of the children led to re-suspension and increased levels of particles. ► In classrooms, mineral dust, building materials and chalk are important sources of particles. ► High CO2 levels indicate that inadequate ventilation contributes for poor IAQ. ► Measurements of outdoor particles do not provide an accurate estimation of children’s exposure.
Keywords: Indoor air; School; Atmospheric particles; Natural ventilation;

A case study designed to investigate indoor and outdoor air quality in naturally ventilated homes near the US-Mexico border was conducted in Nogales, Sonora, Mexico from 14–30 March 2009. To better understand resident’s actual exposure to various sizes of particulate matter (PM), we compare measured concentrations in homes using different household stove cooking fuels (gas versus biomass) and investigate the spatial distribution of outdoor PM. Data from two home locations, one with a gas stove and one with both biomass and gas stoves are evaluated. In each home, continuous PM concentrations were sampled over a range of particle sizes. Indoor and outdoor concentration measurements were facilitated using a valve switching system. PM 2.5 was also sampled on quartz filters located inside and outside of the two homes for carbon analysis. This paper will present a subset of the field data to compare time resolved indoor PM concentrations and carbon content for the two homes; specifically, comparing cooking versus non-cooking time periods. Results indicate that indoor elemental carbon concentrations are dominated by indoor sources during biomass burning, and outdoor sources at all other times. The data indicate that the influence of indoor sources on organic carbon concentrations increases during both gas and biomass stove use; this information is correlated to continuous indoor PM concentrations and home activities. The mean 24 h indoor PM 10 concentration was 408 μg m−3 for the gas stove home and 648 μg m−3 for the home with biomass and gas stoves, while the outdoor concentrations were 609 μg m−3 and 381 μg m−3, respectively. The average 24 h PM 10 Indoor/Outdoor ratio was 0.71 for the gas stove home and 1.79 for the home with both gas and biomass stoves. These ratios should be interpreted with caution as they appear to underestimate the indoor source contribution due to high outdoor PM levels.
Keywords: US-Mexico border; PM; Indoor air quality; Biomass stove; Air pollution;

Air pollutant retention within a complex of urban street canyons by J. Richmond-Bryant; S.S. Isukapalli; D.A. Vallero (7612-7618).
Epidemiological studies of health effects associated with ambient air pollution are subject to uncertainty in the effects estimates related to the spatial and temporal variability of ambient air pollution. This study examines meteorological and concentration decay data for an urban canopy in Oklahoma City, OK to develop a modeling approach that can be used to estimate spatiotemporal variability in contaminant retention that could add bias or uncertainty to epidemiological results. Concentration and microscale turbulent wind data from the Joint Urban 2003 study were reanalyzed to examine scaling relationships between contaminant residence time in urban street canyons, urban boundary layer winds, and urban topography. Street-level sulfur hexafluoride (SF6) concentration time series were reviewed to find time periods that included a peak and decay. Exponential decay curves were fitted to each period, and a characteristic residence time was derived from each model slope. That residence time was nondimensionalized by the ratio of mean urban boundary layer wind speed to height of the building just upwind of the street canyon in which the concentration was measured. Sonic detection and ranging (SODAR) data were used to assess atmospheric turbulence conditions at times concurrent with the concentration decay measurements. Reynolds number (Re) was calculated from the 15-min average wind velocity and ranged from 2.1 × 106 to 7.6 × 107. Nondimensional residence time (H) ranged from 3.7 to 996 with a median of 13.3. Inverse relationships were validated between H and Re and between H and the street canyon aspect ratio. These relationships provided a mechanism to understand time-varying ventilation within a street canyon. The results shown here were intended to demonstrate how scaling relationships derived from the transport equation can be used to provide rapid estimates of characteristic decay times for the purpose of estimating variability in the concentrations encountered in an urban environment. This could be a useful tool to reduce uncertainty in air pollution epidemiological study results related to spatial and temporal variability in urban concentrations.► First known application of pollutant retention theory to street canyon field data. ► Retention significant function of Reynolds number and street canyon aspect ratio. ► Potential tool to reduce uncertainty in air pollution epidemiological study results.
Keywords: Air quality; Air pollution; Dispersion; Epidemiology; Street canyon; Urban;

Estimating historical atmospheric mercury concentrations from silver mining and their legacies in present-day surface soil in Potosí, Bolivia by Nicole Hagan; Nicholas Robins; Heileen Hsu-Kim; Susan Halabi; Mark Morris; George Woodall; Tong Zhang; Allan Bacon; Daniel de B. Richter; John Vandenberg (7619-7626).
Detailed Spanish records of mercury use and silver production during the colonial period in Potosí, Bolivia were evaluated to estimate atmospheric emissions of mercury from silver smelting. Mercury was used in the silver production process in Potosí and nearly 32,000 metric tons of mercury were released to the environment. AERMOD was used in combination with the estimated emissions to approximate historical air concentrations of mercury from colonial mining operations during 1715, a year of relatively low silver production. Source characteristics were selected from archival documents, colonial maps and images of silver smelters in Potosí and a base case of input parameters was selected. Input parameters were varied to understand the sensitivity of the model to each parameter. Modeled maximum 1-h concentrations were most sensitive to stack height and diameter, whereas an index of community exposure was relatively insensitive to uncertainty in input parameters. Modeled 1-h and long-term concentrations were compared to inhalation reference values for elemental mercury vapor. Estimated 1-h maximum concentrations within 500 m of the silver smelters consistently exceeded present-day occupational inhalation reference values. Additionally, the entire community was estimated to have been exposed to levels of mercury vapor that exceed present-day acute inhalation reference values for the general public. Estimated long-term maximum concentrations of mercury were predicted to substantially exceed the EPA Reference Concentration for areas within 600 m of the silver smelters. A concentration gradient predicted by AERMOD was used to select soil sampling locations along transects in Potosí. Total mercury in soils ranged from 0.105 to 155 mg kg−1, among the highest levels reported for surface soils in the scientific literature. The correlation between estimated air concentrations and measured soil concentrations will guide future research to determine the extent to which the current community of Potosí and vicinity is at risk of adverse health effects from historical mercury contamination.► Spanish colonial silver production records can be used to determine smelter emissions. ► Emission rates can be used in a dispersion model to estimate historic Hg exposure. ► Estimated historic air Hg concentrations exceed current inhalation reference values. ► Dispersion model estimates can be used to predict present-day Hg soil gradients. ► Current Hg in soil in Potosí are among the highest levels in urban areas worldwide.
Keywords: Mercury; Silver; AERMOD; Soils; Potosí, Bolivia;

Characterisation of particulates and carcinogenic polycyclic aromatic hydrocarbons in wintertime wood-fired heating in residential areas by Md. Aynul Bari; Guenter Baumbach; Johannes Brodbeck; Michael Struschka; Bertram Kuch; Werner Dreher; Guenter Scheffknecht (7627-7634).
Wood as a renewable and worldwide available fuel is used for residential heating in small-scale firings during winter. This wood combustion can cause very high emissions of inhalable particles resulting in short and long-term health effects. The target of this study was to characterise particulate matter, emissions of polycyclic aromatic hydrocarbons (PAHs) and their size distribution and to show that those emissions can be found in the ambient air of residential areas with wood-fired heating. Emission samples were collected from pellet stove and log wood boiler under different combustion conditions. Ambient PM10 sampling was performed during two winter seasons at two rural residential areas near Stuttgart in Germany. Samples were extracted using toluene with ultrasonic bath and analysed by gas chromatography mass spectrometry (GC–MS). Twenty-one PAH compounds including nine carcinogenic ones were detected and quantified. It was found that emission concentrations of carcinogenic PAHs were higher during incomplete combustion compared to complete combustion. Significant amounts of ambient PAHs were found in the residential villages, where the contribution of carcinogenic PAHs was 44% of total PAHs in the ambient air during winter 2009. The morphology and elemental analysis of ambient particles were also investigated. The findings indicate a rising concern to reduce emissions from wood-fired heating during winter in residential areas and underline the importance of using good wood combustion technologies to improve the air quality.► Wood smoke particles are found mainly in 0.06–0.1 μm range with PM1 of 90% of PM mass. ► Ambient particles are found mainly in 0.7–1.1 μm range with PM2 of 79% of PM10. ► Under incomplete combustion PAH emissions are high in modern wood stove and boiler. ► Estimated total carcinogenic potency underlines health concern in wood-heating areas.
Keywords: Wood-fired heating; Particle size distribution; Wood smoke; Particulate PAHs; Particle morphology;

Physicochemical characterization of fine particles from small-scale wood combustion by Heikki Lamberg; Kati Nuutinen; Jarkko Tissari; Jarno Ruusunen; Pasi Yli-Pirilä; Olli Sippula; Maija Tapanainen; Pasi Jalava; Ulla Makkonen; Kimmo Teinilä; Karri Saarnio; Risto Hillamo; Maija-Riitta Hirvonen; Jorma Jokiniemi (7635-7643).
Emissions from small-scale wood combustion appliances are of special interest since fine particles have been consistently associated with adverse health effects. It has been reported that the physicochemical characteristics of the emitted particles affect also their toxic properties but the mechanisms behind these phenomena and the causative role of particles from wood combustion sources are still mostly unknown. Combustion situations vary significantly in small-scale appliances, especially in batch combustion. Combustion behaviour is affected by fuel properties, appliance type and operational practice. Particle samples were collected from six appliances representing different combustion situations in small-scale combustion. These appliances were five wood log fuelled stoves, including one stove equipped with modern combustion technology, three different conventional combustion appliances and one sauna stove. In addition, a modern small-scale pellet boiler represented advanced continuous combustion technology. The aim of the study was to analyze gas composition and fine particle properties over different combustion situations. Fine particle (PM1) emissions and their chemical constituents emerging from different combustion situations were compared and this physicochemical data was combined with the toxicological data on cellular responses induced by the same particles (see ). There were significant differences in the particle emissions from different combustion situations. Overall, the efficient combustion in the pellet boiler produced the smallest emissions whereas inefficient batch combustion in a sauna stove created the largest emissions. Improved batch combustion with air-staging produced about 2.5-fold PM1 emissions compared to the modern pellet boiler (50.7 mg MJ−1 and 19.7 mg MJ−1, respectively), but the difference in the total particulate PAH content was 750-fold (90 μg MJ−1 and 0.12 μg MJ−1, respectively). Improved batch combustion and conventional batch combustion showed almost the same PM1 emissions (51.6 mg MJ−1), but a 10-fold difference in total particulate PAH emissions (910 μg MJ−1). These results highlight that same PM1 emissions can be associated with very different chemical compositions, potentially leading to different toxic properties of the particles. Thus, changing from an old, less efficient, combustion appliance to a modern appliance can have a greater impact on toxic properties than the emitted PM1 mass might indicate.► Particle and gas emissions from small-scale wood combustion were studied. ► Fine particle properties under different combustion situations were analyzed. ► Modern combustion technologies produced clearly the lowest emissions. ► Same PM1 emissions can lead to potentially different toxic properties of particles.
Keywords: Wood combustion; Emission; Fine particles; Particle characteristics;

Comparison of spatial and temporal variations in p-PAH, BC, and p-PAH/BC ratio in six US counties by Inkyu Han; Juan P. Ramos-Bonilla; Ana M. Rule; Jana N. Mihalic; Lisa M. Polyak; Patrick N. Breysse; Alison S. Geyh (7644-7652).
An ambient air monitoring campaign was performed in six counties (Sacramento, CA; Maricopa, AZ; Anoka, MN; Jefferson, KY; Harris, TX; and Pinellas, FL) between January 2008 and September 2009. The purpose of this paper is to compare the spatial and temporal variability of black carbon (BC) and particle-bound polycyclic aromatic hydrocarbons (p-PAHs), across these counties using continuous monitoring instruments – an Aethalometer and a Photoelectric Aerosol Sensor reporting in units of μg m−3 and fA, respectively. We explored temporal trends in these measurements to assess the potential impact of local combustion sources on air quality. Median BC concentrations ranged from 0.13 to 0.53 μg m−3; and median p-PAH values ranged from 0.31 to 4.18 fA. Hourly BC and p-PAH were elevated during morning rush hour and rapidly decreased later in the morning. Nighttime increases in BC and p-PAH were also observed in most counties. Diurnal patterns of BC and p-PAH were different on weekdays compared to weekends. Profiles of hourly ratios of p-PAH/BC in combination with meteorological data can provide insight into potential sources across the sites. Hourly ratios of p-PAH/BC which peaked during early morning and late afternoon hours suggest a dominating contribution of motor vehicle sources in four of the six counties. In two counties, hourly ratios remained elevated for several hours after rush hour and did not show a distinctive peak suggesting additional sources of BC and p-PAH. Such profiles were seen in both Jefferson KY and Harris TX, and may be attributed to coal combustion, petro-chemical industry and shipping activities, respectively. These results suggest that measurements of BC and p-PAH, combined with meteorological information and emission data are potentially useful to identify combustion sources impacting air quality. More research combining BC and p-PAH measurements with detailed source apportionment data is needed to more fully evaluate the utility of these real-time measures.
Keywords: Combustion source; Black carbon; Particle-bound PAH; Spatial variability; Temporal variability; Ratio;

The concentrations of sixteen polycyclic aromatic hydrocarbons (PAHs) and trace metals adsorbed to respirable particulate matter (PM ≤ 10 μm) and the fine fraction of particulate matter (PM ≤ 2.5 μm) were determined at a site in Delhi (India) during the winter and summer periods in 2007–2008. The annual mean concentrations for PM10 and PM2.5 were 138.5 ± 40.4 μg m−3 and 50.6 ± 20.4 μg m−3, respectively, with higher concentrations during winter than summer period. Concentrations of PM10 and PM2.5 have been found that were higher than the prescribed limits of the WHO and the NAAQS given by CPCB, India. The trace metals detected in the PM10 and PM2.5 were Al, Ca, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn and their concentrations were similar to those observed in heavily polluted urban areas from local traffic and other anthropogenic emissions. Total PAH concentrations for PM10 and PM2.5 were much higher in winter (81.5 and 96 ng m−3, respectively) compared to summer (33.1 and 45.8 ng m−3, respectively) with high molecular weight homologues (4–6 ring PAHs), which account for 80–95.8% of total PAHs. In general, the PM2.5 PAH concentrations were higher than PM10 particles. The results of diagnostic ratio and enrichment factor analyses showed that vehicular and anthropogenic emissions related to combustion, industrial processes as well as natural sources associated with the transport of dust from the roadside area were the main pollutant sources for PAHs and trace metals.
Keywords: Airborne particulate matter; Polycyclic aromatic hydrocarbons; Trace metals; Vehicular emissions; Enrichment factor; Diagnostic ratio;

Particulate polycyclic aromatic hydrocarbons in the urban Northeast Region of China: Profiles, distributions and sources by Weifang Li; Yue Peng; Jianwu Shi; Weiguang Qiu; Jun Wang; Zhipeng Bai (7664-7671).
In this study, concentrations of polycyclic aromatic hydrocarbons (PAHs) associated with PM10 were measured to examine the status, characteristics and sources of atmospheric PAH pollution in the industrial Northeast Region of China. Mean concentrations of total PAHs were 65.5, 40.0, 73.0 and 436.7 ng m−3 in the four seasons respectively. The calculated BaPeq concentrations in winter all exceeded the national standard, imposing serious PAH exposure risk. PAH concentrations varied between the cities, but PAH concentrations in different functional areas within a city did not show significant difference. In general, particulate PAH profiles were dominated by 4- and 5-ring compounds. Elevated proportions of 3-ring PAHs and 5-ring PAHs were found in winter and in summer respectively. Diagnostic ratios and principal component analysis (PCA) were used to identify potential sources of PAHs. Coal combustion activities were the main contributors of particle-associated PAHs in this region.► Particulate PAHs pollution in eight cities of northeast China is investigated. ► Distinct seasonal variations in PAH concentrations and profiles can be observed. ► BaP concentrations in winter all exceed the national standard. ► Coal combustion is found to be the major source.
Keywords: Polycyclic aromatic hydrocarbons; PM10; Ambient concentrations; Distributions; Northeast Region of China;

Long-term study of urban ultrafine particles and other pollutants by Yungang Wang; Philip K. Hopke; David C. Chalupa; Mark J. Utell (7672-7680).
Continuous measurements of number size distributions of ultrafine particles (UFPs) and other pollutants (PM2.5, SO2, CO and O3) have been performed in Rochester, New York since late November 2001. The 2002–2009 average number concentrations of particles in three size ranges (10–50 nm, 50–100 nm and 100–500 nm) were 4730 cm−3, 1838 cm−3, and 1073 cm−3, respectively. The lowest annual average number concentrations of particles in 10–50 nm and 50–100 nm were observed during 2008–2009. The lowest monthly average number concentration of 10–50 nm particles was observed in July and the highest in February. The daily patterns of 10–50 nm particles had two peaks at early morning (7–8 AM) and early afternoon (2 PM). There was a distinct declining trend in the peak number concentrations from 2002–2005 to 2008–2009. Large reductions in SO2 concentrations associated with northerly winds between 2007 and 2009 were observed. The most significant annual decrease in the frequency of morning particle nucleation was observed from 2005 to 2007. The monthly variation in the morning nucleation events showed a close correlation with number concentrations of 10–50 nm particles (r = 0.89). The frequency of the local SO2-related nucleation events was much higher before 2006. All of these results suggest significant impacts of highway traffic and industrial sources. The decrease in particle number concentrations and particle nucleation events likely resulted from a combination of the U.S. EPA 2007 Heavy-Duty Highway Rule implemented on October 1, 2006, the closure of a large coal-fired power plant in May 2008, and the reduction of Eastman Kodak emissions.
Keywords: Ultrafine particles; Urban; Coal-fired power plant; Diesel; Highways; Sulfur;

Development of a new method to estimate the regional and local contributions to black carbon by Paul J. Brochu; Marianthi-Anna Kioumourtzoglou; Brent A. Coull; Philip K. Hopke; Helen H. Suh (7681-7687).
Much attention has been focused on the role of elemental carbon or its surrogate black carbon (BC) in PM-mediated toxicity. It is possible that its toxicity is related to the age or origin of the particles. This study presents methods to apportion ambient BC into its regional and local components and, once estimated, characterizes their seasonal and daily variability.We estimated regional and local BC concentrations in Boston, MA using quantile regression of ambient BC on ambient sulfur. These estimates were compared to estimates obtained using alternative approaches, including quantile regression methods that used sulfate rather than sulfur as a predictor, the use of rural EC concentrations as proxies for regional BC, and source contributions estimated using EPA’s Positive Matrix Factorization (PMF).Regional BC was found to comprise on average 44% of ambient BC in Boston. Mean regional levels equaled 0.289 (±0.126) μg m−3, while average local BC concentrations equaled 0.372 (±0.231) μg m−3. Local BC concentrations varied by season, day of week and hour, with levels highest during weekdays, summer and between 6am and 2pm. Similarly, regional BC concentrations were highest during the summer months. Day of week differences in regional BC concentrations were small. Regional BC did not vary by hour of day. Our estimates agreed well with corresponding estimates of regional and local BC based on sulfate, rural EC concentrations, and PMF methods.Quantile regression is an appropriate method to estimate local and regional BC concentrations. In Boston, we found that regional and local BC comprise approximately equal fractions of total ambient BC. Results suggest the utility of this method for epidemiologic studies and air quality management.► Quantile regression was used to estimate regional & local BC concentrations. ► Regional BC comprises 44% of ambient BC in Boston. ► Higher regional BC levels were observed during summer. ► Higher local BC levels were observed during weekdays and mornings. ► Quantile regression results were validated using other methods.
Keywords: Quantile regression; Black carbon; Regional black carbon; Local black carbon; PMF; Source apportionment;

Source identification of ambient PM2.5 for inhalation exposure studies in Steubenville, Ohio using highly time-resolved measurements by Masako Morishita; Gerald J. Keeler; Ali S. Kamal; James G. Wagner; Jack R. Harkema; Annette C. Rohr (7688-7697).
Recent epidemiological and toxicological studies have suggested that short-term elevations of ambient fine particle mass concentrations (aerodynamic diameter <2.5 μm, PM2.5) can increase cardiac and pulmonary health risks. Thus, examining temporal variations of chemical changes in ambient PM2.5 that could pose the greatest health risks and identifying its sources is critical so that the most toxic categories can be controlled. In this study we collected detailed air quality data in Steubenville, Ohio in August 2006 with the ultimate goal to evaluate associations between cardiovascular (CV) parameters measured in exposed laboratory animals and the chemical and elemental composition of PM2.5. Current approaches using radiotelemetry to measure CV parameters in conscious laboratory animals are capable of collecting continuous recordings. To provide a robust and analogous dataset that can be better matched with CV responses, we have incorporated a highly time-resolved sampling method to characterize trace elements and thereby obtain more robust input data to determine potential emission sources. We applied positive matrix factorization (PMF) to trace element concentrations from 30-minute ambient PM2.5 samples in Steubenville, Ohio, an area designated as a non-attainment area for the PM2.5 National Ambient Air Quality Standards by the Environmental Protection Agency.The average ambient PM2.5 filter-based mass concentration during the 8-hour summer exposure study period was 26 ± 11 μg m−3. Results from PMF indicated that six major factors contributed to the ambient PM2.5 mass during this time: coal combustion/secondary (39 ± 46%), mobile sources (12 ± 14%), metal coating/processing (10 ± 11%), iron and steel manufacturing (5 ± 5%), Pb factor (5 ± 8%), and incineration/smelting (1 ± 3%). The objectives of this paper are (1) to present chemical composition of ambient PM2.5 and its potential emission sources in Steubenville; and (2) to evaluate the PMF modeling results using observed meteorological data. These semi-continuous sampling approaches to determine potential emission sources have significant advantages over similar analyses using samples averaged over 8–24 h, and are being utilized by our group to determine associations of PM with acute CV responses from animal inhalation toxicology field studies.► Information on potential emission sources impacting Steubenville, Ohio was obtained. ► PMF results indicated that six major factors contributed to the ambient PM2.5 mass. ► These results are being utilized for animal inhalation toxicology field studies.
Keywords: Steubenville; PM2.5; Cardiovascular disease; Trace elements; Receptor modeling;

Analysis of black carbon, particulate matter, and gaseous pollutants in an industrial area in Korea by Hee-Jong Yoo; Jungkon Kim; Seung-Muk Yi; Kyung-Duk Zoh (7698-7704).
Continuous mass concentrations of black carbon (BC), particulate matter (PM10 and PM2.5), CO, NO2, SO2, benzene, toluene, and xylene were measured in an industrial area in Incheon City, Korea. Principal component analysis (PCA) results revealed that PC1 had high contributions from PM10, PM2.5, CO, and benzene (31.225%), and was strongly associated with vehicular emissions and industrial sources, the major contributors to air pollution in Incheon. PC2 was heavily enriched with NO2 and BC (24.555%), and was attributed to emissions from vehicles such as buses, vans, taxis, cars, motorcycles, and trucks. PC3 was highly enriched with toluene and xylene (20.884%), and thus represented solvent usage. PC4 was enriched with SO2 (12.884%), which could be attributed to the high S content in diesel fuel used in trucks, which may contribute to the high ambient levels of SO2 in the city. Cluster analysis (CA) revealed four subgroups: Cluster 1 (SO2), Cluster 2 (toluene and xylene), Cluster 3 (NO2 and BC), and Cluster 4 (PM10, PM2.5, CO, and benzene), which agree with the PCA results. This study showed that benzene had a higher correlation with PM2.5, PM10, and CO than toluene and xylene, providing insights into source contributions that, together with a source-species atmospheric dispersion model, can be used to devise new control strategies for industrial urban areas. Our results suggest that appropriate vehicle emission management coupled with industrial air pollution control should be applied to fine particulate (PM2.5) and gaseous pollutants including benzene, toluene, ethylbenzene, and xylenes in the study area.► The application of principal was an effective technique for interpreting chemistry of ambient pollution. ► PCA identified four factors (89.04%) of the ambient pollution in an Industrial area. ► CA showed that benzene was correlated with PM2.5, PM10, and CO than toluene and xylene. ► High SO2 from diesel fuel was concretely identified by combination of PCA and CA.
Keywords: Black carbon; PM2.5; BTEX; Principal component analysis; Cluster analysis;

Key issues in controlling air pollutants in Dhaka, Bangladesh by Bilkis A. Begum; Swapan K. Biswas; Philip K. Hopke (7705-7713).
Particulate matter (PM) sampling for both coarse and fine fractions was conducted in a semi-residential site (AECD) in Dhaka from February 2005 to December 2006. The samples were analyzed for mass, black carbon (BC), and elemental compositions. The resulting data set were analyzed for sources by Positive Matrix Factorization (EPA-PMF). From previous studies, it is found that, the air quality became worse in the dry winter period compared to the rainy season because of higher particulate matter concentration in the ambient air. Therefore, seasonal source contributions were determined from seasonally segregated data using EPA-PMF modeling so that further policy interventions can be undertaken to improve air quality.From the source apportionment results, it is observed that vehicular emissions and emission from brick kiln are the major contributors to air pollution in Dhaka especially in the dry seasons, while contribution from emissions from metal smelters increases during rainy seasons. The Government of Bangladesh is considering different interventions to reduce the emissions from those sources by adopting conversion of diesel/petrol vehicles to CNG, increasing traffic speed in the city and by introducing green technologies for brick production. However, in order to reduce the transboundary effect it is necessary to take action regionally.
Keywords: Positive Matrix Factorization; BC; Traffic; Compressed natural gas; Aerosol or particulate matter (PM); Gent-stacked filter unit;

Air quality impacts of increased use of ethanol under the United States’ Energy Independence and Security Act by Rich Cook; Sharon Phillips; Marc Houyoux; Pat Dolwick; Rich Mason; Catherine Yanca; Margaret Zawacki; Ken Davidson; Harvey Michaels; Craig Harvey; Joseph Somers; Deborah Luecken (7714-7724).
Increased use of ethanol in the United States fuel supply will impact emissions and ambient concentrations of greenhouse gases, “criteria” pollutants for which the U. S. EPA sets ambient air quality standards, and a variety of air toxic compounds. This paper focuses on impacts of increased ethanol use on ozone and air toxics under a potential implementation scenario resulting from mandates in the U. S. Energy Independence and Security Act (EISA) of 2007. The assessment of impacts was done for calendar year 2022, when 36 billion gallons of renewable fuels must be used. Impacts were assessed relative to a baseline which assumed ethanol volumes mandated by the first renewable fuels standard promulgated by U. S. EPA in early 2007. This assessment addresses both impacts of increased ethanol use on vehicle and other engine emissions, referred to as “downstream” emissions, and “upstream” impacts, i.e., those connected with fuel production and distribution. Air quality modeling was performed for the continental United States using the Community Multi-scale Air Quality Model (CMAQ), version 4.7. Pollutants included in the assessment were ozone, acetaldehyde, ethanol, formaldehyde, acrolein, benzene, and 1,3-butadiene. Results suggest that increased ethanol use due to EISA in 2022 will adversely increase ozone concentrations over much of the U.S., by as much as 1 ppb. However, EISA is projected to improve ozone air quality in a few highly-populated areas that currently have poor air quality. Most of the ozone improvements are due to our assumption of increases in nitrogen oxides (NO x ) in volatile organic compound (VOC)-limited areas. While there are some localized impacts, the EISA renewable fuel standards have relatively little impact on national average ambient concentrations of most air toxics, although ethanol concentrations increase substantially. Significant uncertainties are associated with all results, due to limitations in available data. These uncertainties are discussed in detail.
Keywords: Air quality; Modeling; Ethanol; Ozone; Air toxics;