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AIR CONTAMINANT EXPOSURE DURING THE OPERATION OF LAWN AND GARDEN EQUIPMENT
Citation:
BALDAUF, R. W., C. FORTUNE, J. P. WEINSTEIN, M. WHEELER, AND F. BLANCHARD. AIR CONTAMINANT EXPOSURE DURING THE OPERATION OF LAWN AND GARDEN EQUIPMENT. JOURNAL OF EXPOSURE ANALYSIS AND ENVIRONMENTAL EPIDEMIOLOGY. Nature Publishing Group, London, Uk, 16(4):362-370, (2006).
Impact/Purpose:
The main research question guiding this task is "how do mobile source emissions impact public health and the environment." The main objectives of this task include:
(1) Identify spatial and temporal variability in pollutant concentrations near major mobile source emission locations such as urban roadways and non-road activities.
(2) Characterize real-world emissions from on- and non-road mobile sources for use in identifying hazardous components and developing and improving mobile source emissions and human exposure models.
(3) Develop mobile source emission profiles and markers for use in human exposure and air quality receptor models.
(4) Determine the impact of emerging technologies (fuels and engine systems) on emissions and exposures to toxic pollutants.
(5) Develop and improve analytical methods that measure emissions from mobile sources.
Description:
The U.S. Environmental Protection Agency (EPA) initiated the Small Engine Exposure Study (SEES) to evaluate potential exposures among users of small, gasoline-powered, non-road spark-ignition (SI) lawn and garden engines. Equipment tested included riding tractors, walk-behind lawn mowers, string trimmers, and chainsaws. Personal and background air quality measurements were collected on equipment operators for carbon monoxide (CO), particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5), volatile organic compounds (VOCs), and aldehydes. PM2.5 measurements included continuous and integrated mass, elemental and organic carbon (EC/OC), and trace metals. Aldehyde measurements included speciation for formaldehyde and acetaldehyde.
The results demonstrated that equipment operators can experience elevated exposures to CO, PM2.5 and air toxics while operating these engines. Ten-second average CO personal exposures spanned over two orders of magnitude, with short-term concentrations exceeding 120 ppm for some engine applications tested. PM2.5 concentrations averaged over each engine test period also spanned two orders of magnitude. The results also suggest that health standards, such as the CO and PM2.5 National Ambient Air Quality Standards (NAAQS), may be exceeded for certain equipment types under certain operating scenarios. Aldehyde measurements suggested exposures from primary engine emissions that exceed typical ambient concentrations, but do not exceed occupational health standards. Continuous exposure measurements illustrated the important role of the operator's activity and environmental conditions in affecting exposure levels.