Ambient and indoor particulate aerosols generated by dairies in the southern High Plains1

The objectives were to quantify and size ambient aerosolized dust in and around the facilities of 4 southern High Plains dairies of New Mexico and to determine where health of workers might be vulnerable to particulate aerosols, based on aerosol concentrations that exceed national air quality standards. Ambient dust air samples were collected upwind (background) and downwind of 3 dairy location sites (loafing pen boundary, commodity, and compost field). The indoor milking parlor, a fourth site, was monitored immediately upwind and downwind. Aerosolized particulate samples were collected using high-volume sequential reference air samplers, laser aerosol monitors, and cyclone air samplers. The overall (main effects and estimable interactions) statistical general linear model statement for particulate matter (PM10; particulate matter with an aerodynamic diameter of up to 10 μm) and PM2.5 resulted in a greater mean concentration of dust in the winter (PM10 = 97.4 ± 4.4 μg/m3; PM2.5 = 32.6 ± 2.6 μg/m3) compared with the summer (PM10 = 71.9 ± 5.0 μg/m3; PM2.5 = 18.1 ± 1.2 μg/m3). The upwind and downwind boundary PM10 concentrations were significantly higher in the winter (upwind = 64.3 ± 9.5 μg/m3; downwind = 119.8 ± 13.0 μg/m3) compared with the summer (upwind = 35.2 ± 7.5 μg/m3; downwind = 66.8 ± 11.8 μg/m3). The milking parlor PM10 and PM2.5 concentration data were significantly higher in the winter (PM10 = 119.5 ± 5.8 μg/m3; PM2.5 = 55.3 ± 5.8 μg/m3) compared with the summer (PM10 = 88.6.0 ± 5.8 μg/m3; PM2.5 = 21.0 ± 2.1 μg/m3). Personnel should be protected from high aerosol concentrations found at the commodity barn, compost field, and milking parlor during the winter.