Local traffic patterns and proximity to pollution sources are important in assessing particulate matter (PM) exposure in urban communities. This study investigated the intra-community spatial variation of PM in an urban area impacted by numerous local and regional sources. Weekly size-segregated (<0.25, 0.25–2.5, and >2.5 μm) PM samples were collected in the winter of 2005. During each 1-week sampling cycle, data were collected concurrently at four sites within four miles of one another in the Long Beach, CA area. Coefficients of divergence analyses for size-fractionated PM mass, organic and elemental carbon, sulfur, and 18 other metals and trace elements suggest a wide range of spatial divergence. High spatial variability was observed in the <0.25 μm and 0.25–2.5 μm PM fractions for many elements associated with motor vehicle emissions. Relatively lower spatial divergence was observed in the coarse fraction, although road dust components were spatially diverse but highly correlated with each other. Mass and OC concentrations were homogeneously distributed over the sampling sites. Possible oil combustion sources were identified using previously documented markers such as vanadium and nickel and by distinguishing between primary sulfur and secondary sulfate contributions. This study shows that, although PM mass in different size fractions is spatially homogeneous within a community, the spatial distribution of some elemental components can be heterogeneous. This is evidence for the argument that epidemiological studies using only PM mass concentrations from central sites may not accurately assess exposure to toxicologically relevant PM components.
"While particulate mass concentrations can be spatially homogeneous, certain toxic particulate components may be unevenly distributed originating from specific sources, creating a potential for exposure of large populations to healthrelevant particulate components (Krudysz et al. 2008). Assessing population exposure to particulates thus requires evaluation of the communityscale spatial variability representing different elemental particulates as well as toxicologically relevant components. "
[Show abstract][Hide abstract] ABSTRACT: This study proposes a practical method to estimate elemental composition and distribution in order to attribute source and quantify impacts of aerosol particles at an urban region in Kolkata, India. Twelve-hour total particulates were collected in winter (2005-2006) and analyzed by energy-dispersive X-ray fluorescence technique to determine multi-elemental composition, especially trace metals. The aerosols consist of various elements including K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, and Pb which exhibit significant concentration at various sites (p < 0.05). The concentration of different metallic elements were found in the order of Zn > Pb > Ni > Cu > Cr > Co. Statistical multivariate analysis and correlation matrix analyses were performed for factor identification and consequent source apportionment. Contour profiles demonstrate spatial variation of elemental compositions indicating possible source contribution along with meteorological influences. Spatial differences were clearly most significant for Zn, Ni, Pb, and Cu reflecting the importance of anthropogenic inputs, primarily from automobile sources.
"Finally, we estimated pairwise Coefficients of Divergence (COD) to assess the degree of uniformity in the PM 2.5 concentrations as well as absolute differences in the PM 2.5 chemical compositions among the sites. COD has been used as a complementary measure to correlation analysis, to characterize spatial patterns of particulate matter in several multi-site comparative analyses (Wongphatarakul et al., 1998; Pinto et al., 2004; Kim et al., 2005; Krudysz et al., 2008). In this context, two sites may exhibit strong linear associations with each other in total PM 2.5 mass, yet have absolute levels that differ substantially; yielding both high correlations and high COD values. "
[Show abstract][Hide abstract] ABSTRACT: This manuscript presents results from an extensive, multi-country comparative monitoring study of fine particulate matter (PM2.5) and its primary chemical components in Israeli, Jordanian and Palestinian cities. This study represented the first time that researchers from these countries have worked together to examine spatial and temporal relationships for PM2.5 and its major components among the study sites. The findings indicated that total PM2.5 mass was relatively homogenous among many of the 11 sites as shown from strong between-site correlations. Mean annual concentrations ranged from 19.9 to 34.9 μg m−3 in Haifa and Amman, respectively, and exceeded accepted international air quality standards for annual PM2.5 mass. Similarity of total mass was largely driven by SO42− and crustal PM2.5 components. Despite the close proximity of the seven, well correlated sites with respect to PM2.5, there were pronounced differences among the cities for EC and, to a lesser degree, OC. EC, in particular, exhibited spatiotemporal trends that were indicative of strong local source contributions. Interestingly, there were moderate to strong EC correlations (r > 0.65) among the large metropolitan cities, West Jerusalem, Tel Aviv and Amman. For these relatively large cities, (i.e., West Jerusalem, Tel Aviv and Amman), EC sources from the fleet of buses and cars typical for many urban areas predominate and likely drive spatiotemporal EC distributions. As new airshed management strategies and public health interventions are implemented throughout the Middle East, our findings support regulatory strategies that target integrated regional and local control strategies to reduce PM2.5 mass and specific components suspected to drive adverse health effects of particulate matter exposure.
"Sampling sites and data collection are described in detail elsewhere (Krudysz et al. 2008). Briefly, the ambient PM samples used in this study were collected by personal cascade impactor samplers (PCIS) on Teflon and quartzfiber filters over a 10-week period from January to March 2005. "
[Show abstract][Hide abstract] ABSTRACT: Quantification of the size distributions of organic molecular markers can provide information about the origin of the carbonaceous
particulate matter (PM). Organic molecular marker spatial variability studies provide data that are vital to an accurate determination
of a population's exposure to PM from various sources. We have investigated the intra-community spatial variation of size-segregated
PM [0–0.25μm (ultrafine), 0.25-2.5μm (accumulation), and 2.5-10μm (coarse)) ] in a southern California community. The highest
concentrations of individual organic compounds were found in the ultrafine fraction, followed by the accumulation and coarse
size fractions. Correlations between the three size fractions were weak between compounds in the coarse and corresponding
ultrafine and accumulation particles, implying that the coarse PM organic compounds were emitted by different sources than
those that emit ultrafine and accumulation mode PM. Evidence of the incomplete combustion of gasoline was found in the ultrafine
and accumulation size fractions, while possible diesel emissions were traced to ultrafine particles. Coefficients of divergence
and coefficients of variation were investigated to determine the spatial and temporal variability of individual organic compounds.
Spatial divergence in organic compounds was comparatively high, but it did not differ appreciably between size fractions or
between compound classes. Elemental carbon and tracer compounds, which originate from a few sources, showed higher spatial
divergence than organic carbon whose numerous sources can be local and regional. Spatial and temporal variability were not
different from each other for this data set and, therefore, it is not possible to determine whether variability in concentrations
between sampling sites or the length of the sampling campaign is more important for health effects studies.
Air Quality Atmosphere & Health 06/2009; 2(2):69-88. DOI:10.1007/s11869-009-0035-1 · 1.80 Impact Factor
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