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United States Department of Agriculture

Agricultural Research Service

Title: Application of the National Ambient Air Quality Standards (Naaqs) in Urban Versus Rural Environments

Authors
item Shaw, Bryan - TEXAS A&M UNIVERSITY
item Lacey, Ron - TEXAS A&M UNIVERISTY
item Capareda, Sergio - TEXAS A&M UNIVERSITY
item Buser, Michael
item Parnell, JR., Calvin - TEXAS A&M UNIVERSITY
item Wanjura, John - TEXAS A&M UNIVERSITY
item Wang, Lingjuan - TEXAS A&M UNIVERSITY
item Faulkner, William - TEXAS A&M UNIVERSITY

Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: August 5, 2004
Publication Date: August 5, 2004
Citation: Shaw, B.W., Lacey, R.E., Capareda, S., Buser, M.B., Parnell, Jr., C.B., Wanjura, J., Wang, L., Faulkner, W.B. 2004. Application of the National Ambient Air Quality Standards (NAAQS) in urban versus rural environments. American Society of Agricultural Engineers. Paper No. 044016.

Interpretive Summary: The U.S. Environmental Protection Agency is currently assessing the need for a national particulate matter coarse fraction standard. The designation of the term coarse fraction refers to the mass of particulate matter relating to particles with diameters between 2.5 and 10 microns. EPA is primarily relying on epidemiological studies to make this assessment. These epidemiological studies utilize data from size-selective particulate matter samplers to estimate the study population's exposure to the coarse fraction of particulate matter. Further, these studies typically focus on urban populations in order to obtain sufficient sample sizes and to increase the statistical certainty of the studies findings. This focus on urban environments has resulted in a lack of information on the effect of coarse particulate matter in rural environments. There are a number of key differences between urban and rural environments in the United States that can lead to economically costly mistakes in applying data from urban studies to rural environments. These differences include: differing sources of particulate matter which relates to differences in the particle size distribution and composition of particles being emitted from these sources, and most importantly, these EPA approved samplers used in these studies perform differently in rural environments, as compared to urban environments. This basically means that the samplers are over-sampling in rural environments, as compared to urban environments, and by basing a particulate matter standard on studies conducted urban environments, this standard will lead to unwarranted regulatory burdens being placed on the businesses and citizens in rural America.

Technical Abstract: The U.S. Environmental Protection Agency is currently assessing the need for a National Ambient Air Quality Standard for the coarse fraction of particulate material (PMCF), specifically, the fraction of particulate matter between 2.5 and 10 microns in aerodynamic equivalent diameter. EPA is primarily relying on epidemiological studies that examine the possible health effects of PMCF to reach a decision about developing a coarse particulate matter standard. These epidemiological studies utilize data from size-selective PM samplers to estimate the study population's exposure to PM10, PM2.5, and PMCF. Epidemiological studies typically focus on urban populations in order to obtain sufficient sample size and increase statistical certainty of study findings. This focus on urban environments has resulted in a lack of studies evaluating the effect of coarse particulate matter in rural environments. There are a number of key differences between the urban and rural environments in the United States that can lead to mistakes in applying data from urban studies to rural environments. These include differences in particle sources, affecting particle size distribution and composition, differences in the concentration of gaseous co-pollutants, and differences in PM sampler performance in the two environments. It is our contention that these differences between the urban and rural environment are significant and that the epidemiological studies cited by EPA rely on data that are not representative of rural environments, raising concerns that the implementation of a PMCF standard in rural environments will impose an unfair and unwarranted regulatory burden on the businesses and citizens in these areas.

Last Modified: 9/10/2014
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