Spatial–temporal and cancer risk assessment of selected hazardous air pollutants in Seattle
Introduction
Hazardous air pollutants (HAPs, or ‘air toxics’) are pollutants that are known or suspected to cause adverse health effects, including cancer, reproductive, immunological, developmental, and neurological effects (USEPA, 2004). There are currently 188 HAPs regulated under the US federal Clean Air Act Amendments of 1990. To identify those air toxics which are of greatest concern in terms of contribution to population risk, the USEPA established the National-scale Air Toxics Assessment (NATA) projects (USEPA, 2002, USEPA, 2006, USEPA, 2009d). Several studies also performed additional risk assessments and modeling evaluation based on the predicted exposure concentrations from NATA (Loh et al., 2007, Ozkaynak et al., 2008, Woodruff et al., 2000). The NATA projects relied heavily on the modeling approach. The accuracy of the concentration predictions and risk estimates depends on the completeness of the National Emissions Inventory and meteorological data. It has been reported that the modeling results for most HAPs were underestimated by a factor of 2 or more (Payne-Sturges et al., 2004, USEPA, 2006).
Several studies have been conducted to evaluate the population exposure to HAPs using limited ambient monitoring data. At the national scale, Touma et al. (2006) summarized the data collected under the National Air Toxics Trends Stations monitoring network. McCarthy et al. (2009) compiled ambient measurements of air toxics collected in the US from 2003 through 2005 and calculated risk-weighted concentrations. They found that concentrations for benzene, 1,3-butadiene, carbon tetrachloride, acetaldehyde, and arsenic were above levels of concern for cancer risks at most monitoring locations. At the regional scale, air quality measurements of volatile organic compounds (VOCs) were collected at 13 urban locations in the eastern US (Mohamed et al., 2002). The results showed that levels of carbonyls were higher than those for other organic compounds groups, especially for formaldehyde and acetaldehyde. Under the Urban Air Toxics Monitoring Program, Bortnick and Stetzer (2002) showed that temporal variability comprises most of the overall variability across 12 cities. In spite of these findings, questions about the spatial and temporal variability within individual cities still remain. Not many studies investigate this issue at a local scale and they tend to focus on analyzing VOCs, but not on particulate matter (PM) elements (Mohamed et al., 2002).
Seattle was one of six cities selected by the U.S. EPA to participate in the National Air Toxics Monitoring Pilot Program. VOCs and PM elements were monitored at six sites within Seattle for a year. This dataset provides unique opportunities to evaluate the intraurban variation of air toxics. In this study, we quantify the relative contribution of the temporal and spatial components to overall data variability. This type of analysis is useful when designing monitoring networks for air toxics. We further estimate the potential health risk based on the monitored data.
Section snippets
Study design
The monitoring sites included neighborhood to urban scale locations in distinctly different sub-regions within the Seattle metropolitan area selected to allow the evaluation of spatial variability. These included Beacon Hill (BH, regional scale), Georgetown (GT, industrial), Lake Samamish (LS, Background), Lake Forest Park (LF, neighborhood, wood smoke impact site), SeaTac (ST, mobile and airport), and Mapleleaf reservoir (ML, neighborhood) (Fig. 1). The VOCs measured included benzene,
Quality control and summary statistics
The method detection limit (MDL) for metals analyzed with XRF ranged between 0.50 ng/m3 for nickel and 4.21 ng/m3 for cadmium. The MDL for ICP-MS (Table 1) was 1.3 (chromium) to 145 (cadmium) times more sensitive than those of XRF. Collocated samples, one using the FRM for PM2.5 on a Teflon filter subject to XRF analysis and the other using the High-Vol sampler for TSP on a quartz filter subject to ICP-MS analysis, were collected between August 2001 and January 2002 at the ML site (N = 22 pairs
Conclusions
This study evaluates the spatial and temporal variations of 15 air toxics in Seattle, WA. It was found that the associated temporal component of variation was generally larger than the spatial component. The principal component analysis also shows that the temporal factor was more dominant. Nevertheless, differences among the locations after accounting for temporal effects cannot be denied. These results suggest that operating multiple air toxics monitoring sites over a significant period of
Acknowledgements
The Seattle monitoring study was conducted as a collaborative effort among the US EPA Region X, the Washington State Department of Ecology (the Ecology), the Puget Sound Clean Air Agency, the Washington State University, and the University of Washington. This study was funded by the Ecology under a cooperative agreement with the Washington Cooperative Fish & Wildlife Research Unit. This study was also partially funded by the U.S. Environmental Protection Agency through its Office of Research
References (35)
- et al.
Sources of variability in ambient air toxics monitoring data
Atmos Environ
(2002) - et al.
Spatial and temporal trend evaluation of ambient concentrations of 1, 3-butadiene and chloroprene in Texas
Chem Biol Interact
(2007) - et al.
Temporal variability of selected air toxics in the United States
Atmos Environ
(2007) - et al.
Volatile organic compounds in some urban locations in United States
Chemosphere
(2002) - et al.
Variability of hazardous air pollutants in an urban area
Atmos Environ
(1996) - et al.
A human health assessment of hazardous air pollutants in Portland, OR
J Environ Manage
(2004) - et al.
Estimating cancer risk from outdoor concentrations of hazardous air pollutants in 1990
Environ Res
(2000) - et al.
Source apportionment of PM2.5 and selected hazardous air pollutants in Seattle
Sci Total Environ
(2007) - et al.
Cancer risk assessment of selected hazardous air pollutants in Seattle
Environ Int
(2009) Draft toxicological profile for Manganese
(2008)
Air toxics hot spots program risk assessment guidelines: part II technical support document for describing available cancer potency factors
An introduction to the bootstrap
Applied multivariate methods for data analysts
Estimation of organic carbon blank values and error structures of the speciation trends network data for source apportionment
J Air Waste Manage Assoc
Applied regression analysis and other multivariable methods
Exposure assessment of particulate matter for susceptible populations in Seattle
Environ Health Perspect
Ranking cancer risks of organic hazardous air pollutants in the United States
Environ Health Perspect
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Contributed equally to this work.