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California dairies house approximately 1.8 million lactating and 1.5 million dry cows and heifers. State air regulatory agencies view these dairies as a major air pollutant source, but emissions data are sparse, particularly for volatile organic compounds (VOCs). The objective of this work was to determine V0C emissions from lactating and dry dairy cows and their waste using an environmental chamber. Carbon dioxide and methane were measured to provide context for the V0Cs. VOCs were measured by proton-transfer-reaction mass spectrometry (PTR-MS). The compounds with highest fluxes when cows plus waste were present were methanol, acetone + propanal, dimethylsulfide, and m/z 109 (likely 4-methyl-phenol). The compounds with highest fluxes from fresh waste (urine and feces) were methanol, m/z 109, and m/z 60 (likely trimethylamine). Ethanol fluxes are reported qualitatively, and several VOCs that were likely emitted (formaldehyde, methylamine, dimethylamine) were not detectable by PTR-MS. The sum of reactive VOC fluxes measured when cows were present was a factor of 6–10 less than estimates historically used for regulatory purposes. In addition, ozone formation potentials of the dominant VOCs were ∼10% those of typical combustion or biogenic VOCs. Thus dairy cattle have a comparatively small impact on ozone formation per VOC mass emitted. [ABSTRACT FROM AUTHOR]

Two collaborative studies have been conducted by the U.S. Environmental Protection Agency (EPA) National Exposure Research Laboratory (NERL) and National Health and Environmental Effects Research Laboratory to determine personal exposures and physiological responses to particulate matter (PM) of elderly persons living in a retirement facility in Fresno, CA. Measurements of PM and other criteria air pollutants were made inside selected individual residences within the retirement facility and at a central outdoor site on the premises. In addition, personal PM exposure monitoring was conducted for a subset of the participants, and ambient PM monitoring data were available for comparison from the NERL PM research monitoring platform in central Fresno. Both a winter (February 1-28, 1999) and a spring (April 19-May 16, 1999) study were completed so that seasonal effects could be evaluated. During the spring study, a more robust personal exposure component was added, as well as a more detailed evaluation of physical factors, such as air-exchange rate, that are known to influence the penetration of particles into the indoor environment. In this paper, comparisons are made among measured personal PM exposures and PM mass concentrations measured at the NERL Fresno Platform site, outside on the premises of the retirement facility, and inside selected residential apartments at the facility during the two 28-day study periods. The arithmetic daily mean personal PM[sub2.5] exposure during the winter study period was 13.3 µg/m³, compared with 9.7, 20.5, and 21.7 µg/m³ for daily mean overall apartment, outdoor, and ambient (i.e., platform) concentrations, respectively. The daily mean personal PM[sub2.5] exposure during the spring study period was 11.1 µg/m³, compared with 8.0, 10.1, and 8.6 µg/m³ for the daily mean apartment, outdoor, and ambient concentrations, respectively. [ABSTRACT FROM AUTHOR]