Rachelle M. Duvall

Quantifying the Impact of Residential Heating on the Urban Air Quality in a Typical European Coal Combustion Region

The present investigation, carried out as a case study in a typical major city situated in a European coal combustion region (Krakow, Poland), aims at quantifying the impact on the urban air quality of residential heating by coal combustion in comparison with other potential pollution sources such as power plants, industry, and traffic. Emissions were measured for 20 major sources, including small stoves and boilers, and the particulate matter (PM) was analyzed for 52 individual compounds together with outdoor and indoor PM10 collected during typical winter pollution episodes. The data were analyzed using chemical mass balance modeling (CMB) and constrained positive matrix factorization (CMF) yielding source apportionments for PM10, B(a)P, and other regulated air pollutants namely Cd, Ni, As, and Pb. The results are potentially very useful for planning abatement strategies in all areas of the world, where coal combustion in small appliances is significant. During the studied pollution episodes in Krakow, European air quality limits were exceeded with up to a factor 8 for PM10 and up to a factor 200 for B(a)P. The levels of these air pollutants were accompanied by high concentrations of azaarenes, known markers for inefficient coal combustion. The major culprit for the extreme pollution levels was demonstrated to be residential heating by coal combustion in small stoves and boilers (>50% for PM10 and >90% B(a)P), whereas road transport (<10% for PM10 and <3% for B(a)P), and industry (4-15% for PM10 and <6% for B(a)P) played a lesser role. The indoor PM10 and B(a)P concentrations were at high levels similar to those of outdoor concentrations and were found to have the same sources as outdoors. The inorganic secondary aerosol component of PM10 amounted to around 30%, which for a large part may be attributed to the industrial emission of the precursors SO2 and NOx.

Comparative Toxicity of Size-Fractionated Airborne Particulate Matter Obtained from Different Cities in the United States

Hundreds of epidemiological studies have shown that exposure to ambient particulate matter (PM) is associated with dose-dependent increases in morbidity and mortality. While early reports focused on PM less than 10 μm (PM10), numerous studies have since shown that the effects can occur with PM stratified into ultrafine (UF), fine (FI), and coarse (CO) size modes despite the fact that these materials differ significantly in both evolution and chemistry. Furthermore the chemical makeup of these different size fractions can vary tremendously depending on location, meteorology, and source profile. For this reason, high-volume three-stage particle impactors with the capacity to collect UF, FI, and CO particles were deployed to four different locations in the United States (Seattle, WA; Salt Lake City, UT; Sterling Forest and South Bronx, NY), and weekly samples were collected for 1 mo in each place. The particles were extracted, assayed for a standardized battery of chemical components, and instilled into mouse lungs (female BALB/c) at doses of 25 and 100 μg. Eighteen hours later animals were euthanized and parameters of injury and inflammation were monitored in the bronchoalveolar lavage fluid and plasma. Of the four locations, the South Bronx coarse fraction was the most potent sample in both pulmonary and systemic biomarkers, with a strong increase in lung inflammatory cells as well as elevated levels of creatine kinase in the plasma. These effects did not correlate with lipopolysaccharide (LPS) or total zinc or sulfate content, but were associated with total iron. Receptor source modeling on the PM2.5 samples showed that the South Bronx sample was heavily influenced by emissions from coal fired power plants (31%) and mobile sources (22%). Further studies will assess how source profiles correlate with the observed effects for all locations and size fractions.

Impact of Mine Waste on Airborne Respirable Particulates in Northeastern Oklahoma, United States

Abstract Atmospheric dispersion of particles from mine waste is potentially an important route of human exposure to metals in communities close to active and abandoned mining areas. This study assessed sources of mass and metal concentrations in two size fractions of respirable particles using positive matrix factorization (U.S. Environmental Protection Agency [EPA] PMF 3.0). Weekly integrated samples of particulate matter (PM) 10 µm in aerodynamic diameter or less (PM10) and fine PM (PM2.5, or PM <2.5 µm in aerodynamic diameter) were collected at three monitoring sites, varying distances (0.5–20 km) from mine waste piles, for 58 consecutive weeks in a former lead (Pb) and zinc (Zn) mining region. Mean mass concentrations varied significantly across sites for coarse PM (PM10–PM2.5) but not PM2.5 particles. Concentrations of Pb and Zn significantly decreased with increasing distance from the mine waste piles in PM10–PM2.5 (P < 0.0001) and PM2.5 (P < 0.0005) fractions. Source apportionment analyses deduced five sources contributing to PM2.5 (mobile source combustion, secondary sulfates, mine waste, crustal/soil, and a source rich in calcium [Ca]) and three sources for the coarse fraction (mine waste, crustal/soil, and a Ca-rich source). In the PM2.5 fraction, mine waste contributed 1–6% of the overall mass, 40% of Pb, and 63% of Zn. Mine waste impacts were more apparent in the PM10–PM2.5 fraction and contributed 4–39% of total mass, 88% of Pb, and 97% of Zn. Percent contribution of mine waste varied significantly across sites (P < 0.0001) for both size fractions, with highest contributions in the site closest to the mine waste piles. Seasonality, wind direction, and concentrations of the Ca-rich source were also associated with levels of ambient aerosols from the mine waste source. Scanning electron microscopy results indicated that the PMF-identified mine waste source is mainly composed of Zn-Pb agglomerates on crustal particles in the PM10–PM2.5 fraction. In conclusion, the differential impacts of mine waste on respirable particles by size fraction and location should be considered in future exposure evaluations.

Assessing the Role of Particulate Matter Size and Composition on Gene Expression in Pulmonary Cells

Identifying the mechanisms by which air pollution causes human health effects is a daunting task. Airsheds around the world are composed of pollution mixtures made up of hundreds of chemical and biological components with an extensive array of physicochemical properties. Current in vivo approaches are limited to the identification of associations between pollutants and health but do not allow for the identification of precise biological mechanisms of effect or the component(s) responsible for the effect. High-throughput in vitro methods using relevant cell culture systems and microarray technology allow researchers to evaluate the mechanisms by which air pollutants affect human health. Our studies have used human airway epithelial cells primarily to test the toxicological effects of particles of different sizes and of various particle components from several cities across the United States. Chemical mass balance analysis is also being used to analyze these samples to establish links between physicochemical properties of particulate matter (PM) and potential sources. The ultimate goal of this line of research is to link the mechanistic data to the PM source data in order to gain an understanding about how the components and sources of PM affect human health.

Chemical composition and source apportionment of size fractionated particulate matter in Cleveland, Ohio, USA ☆

The Cleveland airshed comprises a complex mixture of industrial source emissions that contribute to periods of non-attainment for fine particulate matter (PM2.5) and are associated with increased adverse health outcomes in the exposed population. Specific PM sources responsible for health effects however are not fully understood. Size-fractionated PM (coarse, fine, and ultrafine) samples were collected using a ChemVol sampler at an urban site (G.T. Craig (GTC)) and rural site (Chippewa Lake (CLM)) from July 2009 to June 2010, and then chemically analyzed. The resulting speciated PM data were apportioned by EPA positive matrix factorization to identify emission sources for each size fraction and location. For comparisons with the ChemVol results, PM samples were also collected with sequential dichotomous and passive samplers, and evaluated for source contributions to each sampling site. The ChemVol results showed that annual average concentrations of PM, elemental carbon, and inorganic elements in the coarse fraction at GTC were ∼2, ∼7, and ∼3 times higher than those at CLM, respectively, while the smaller size fractions at both sites showed similar annual average concentrations. Seasonal variations of secondary aerosols (e.g., high NO3- level in winter and high SO42- level in summer) were observed at both sites. Source apportionment results demonstrated that the PM samples at GTC and CLM were enriched with local industrial sources (e.g., steel plant and coal-fired power plant) but their contributions were influenced by meteorological conditions and the emission sources operation conditions. Taken together the year-long PM collection and data analysis provides valuable insights into the characteristics and sources of PM impacting the Cleveland airshed in both the urban center and the rural upwind background locations. These data will be used to classify the PM samples for toxicology studies to determine which PM sources, species, and size fractions are of greatest health concern.

The Detroit Exposure and Aerosol Research Study

The Detroit Exposure and Aerosol Research Study (DEARS) was designed to assess the impacts of local industrial and mobile sources on human exposures to air pollutants in and around Detroit, Michigan. Daily integrated measurements were made of personal exposure, and residential indoor and outdoor concentrations in six neighborhoods throughout the Detroit area. Concurrent data were collected for comparison at a central community ambient monitoring location and a regional background site. These data collected in DEARS can be used to evaluate local air quality and explore the application of air quality models to assess human exposure in an urban area.

Source Apportionment of Particulate Matter in the U.S. and Associations with In Vitro and In Vivo Lung Inflammatory Markers

Associations are well established between particulate matter (PM) and increased human mortality and morbidity. Fine particulate matter (particle diameter < 2.5 Pm) is most strongly linked to adverse health impacts. The toxicity of PM may depend on the PM source and composition which will vary by location. While a number of epidemiological studies have shown that certain PM sources are associated with specific health outcomes, the underlying mechanisms are still unclear. To investigate these mechanisms, continuous weekly PM2.5 samples were collected for four consecutive weeks (24 hours a day for seven days) in six cities across the U.S. as part of the Multiple Air Pollutant Study (MAPS). Sample composites were constructed for each site and particles were extracted in water. Samples were analyzed for trace metals (via Inductively Coupled Plasma - Optical Emission Spectroscopy), ions (via Ion Chromatography), and elemental carbon (via thermal methods). Sources contributing to the PM2.5 samples were identified using the EPA Chemical Mass Balance (CMB8.2) model. Both in vitro and in vivo experiments were conducted to measure a variety of toxicological out- comes. For the in vitro analysis, PM extracts were applied to cultured human lung epithelial cells and the production of different lung inflammation/injury markers (Table 1) was measured by real-time reverse transcriptase polymerase chain reaction (RT-PCR). For the in vivo analysis, particle extracts were instilled into mouse lungs at different doses (25 and 100 Pg). Indicators of lung injury and inflammation (Table 1) were measured in bronchoalveolar lavage fluid and plasma by enzyme-linked immunosorbent assay (ELISA). The relationship between the toxicological measures and PM2.5 sources was eva- luated using linear regression. A few of these plots are displayed in Figure 1. For the in vitro health markers, mobile sources and secondary sulfate (from coal com- bustion) were related to increased IL-8 production (r 2 = 0.39 and r 2 = 0.79, respectively). Combustion sources and soil were associated with increases in COX- 2 (r 2 = 0.38 and r 2 = 0.48), and secondary sulfate was associated with increased HO- 1 (r 2 = 0.51). For the in vivo health markers, wood combustion was associated with increased MIP-2 production (r 2 = 0.95), whereas mobile sources were associated with increased IL1-E and TNF-D (r 2 = 0.94 and r 2 = 0.99, respectively). These findings confirm that PM2.5 sources are associated with specific health outcomes.