| Estimating Risk from Ambient Concentrations of Acrolein across the United States Tracey J. Woodruff,1,2 Ellen M. Wells,3 Elizabeth W. Holt,4 Deborah E. Burgin,5 and Daniel A. Axelrad6 1Office of Policy, Economics and Innovation, U.S. Environmental Protection Agency, San Francisco, California, USA; 2University of California, San Francisco, San Francisco, California, USA; 3Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA; 4Department of Epidemiology and Public Health, School of Medicine, Yale University, New Haven, Connecticut, USA; 5Office of Environmental Information, and 6Office of Policy, Economics and Innovation, U.S. Environmental Protection Agency, Washington, DC, USA Abstract
Background: Estimated ambient concentrations of acrolein, a hazardous air pollutant, are greater than the U.S. Environmental Protection Agency (EPA) reference concentration throughout the United States, making it a concern for human health. However, there is no method for assessing the extent of risk under the U.S. EPA noncancer risk assessment framework. Objectives: We estimated excess risks from ambient concentrations of acrolein based on dose–response modeling of a study in rats with a relationship between acrolein and residual volume/total lung capacity ratio (RV/TLC) and specific compliance (sCL) , markers for altered lung function. Methods: Based on existing literature, we defined values above the 90th percentile for controls as "adverse." We estimated the increase over baseline response that would occur in the human population from estimated ambient concentrations of acrolein, taken from the U.S. EPA's National-Scale Air Toxics Assessment for 1999, after standard animal-to-human conversions and extrapolating to doses below the experimental data. Results: The estimated median additional number of adverse sCL outcomes across the United States was approximately 2.5 cases per 1,000 people. The estimated range of additional outcomes from the 5th to the 95th percentile of acrolein concentration levels across census tracts was 0.28–14 cases per 1,000. For RV/TLC, the median additional outcome was 0.002 per 1,000, and the additional outcome at the 95th percentile was 0.13 per 1,000. Conclusions: Although there are uncertainties in estimating human risks from animal data, this analysis demonstrates a method for estimating health risks for noncancer effects and suggests that acrolein could be associated with decreased respiratory function in the United States. Key words: acrolein, dose response, hazardous air pollutants (HAPs) , noncancer risk assessment, respiratory function. Environ Health Perspect 115:410–415 (2007) . doi:10.1289/ehp.9467 available via http://dx.doi.org/ [Online 11 December 2006]
Address correspondence to T.J. Woodruff, Institute for Health Policy Studies, 3333 California St., Suite 265, San Francisco, CA 94118-1981 USA. Telephone: (415) 476-1890. E-mail: tracey.woodruff@ucsf.edu Supplemental Material is available online at http://www.ehponline.org/docs/2006/9467/suppl.pdf We thank D. Costa for providing data and J. Gift and K. Hogan for technical guidance. Views in this article represent those of the authors and not necessarily the U.S. Environmental Protection Agency ; reference to commercial products or trade names does not constitute endorsement or recommendation for use. The authors declare they have no competing financial interests. Received 28 June 2006 ; accepted 11 December 2006.
The full version of this article is available for free in HTML or PDF formats. |
