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Air contaminant exposures during the operation of lawn and garden equipment


The US 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 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 p.p.m. 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.

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We acknowledge the efforts of others who contributed to this project. Carl Scarbro, Chris Lieske, and Phil Carlson of the US Environmental Protection Agency's (EPA) Office of Transportation and Air Quality (OTAQ) assisted in identifying appropriate equipment for testing, and procuring the actual equipment tested. Ron Williams and Don Whitaker of EPA's Office of Research and Development and Chad Bailey of OTAQ provided valuable assistance in designing and implementing the study.

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Correspondence to Richard Baldauf.

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The United States Environmental Protection Agency through its Office of Research and Development funded and managed the research described here under Contract 68-D-00-206 to ManTech Environmental Technology Incorporated. It has been subjected to Agency review and approved for publication.

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Baldauf, R., Fortune, C., Weinstein, J. et al. Air contaminant exposures during the operation of lawn and garden equipment. J Expo Sci Environ Epidemiol 16, 362–370 (2006).

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  • lawn and garden equipment
  • exposure assessment
  • carbon monoxide
  • particulate matter
  • air toxics
  • non-road mobile sources.

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