aRelative importance of emissions from AFOs at spatial scales based on committees’ informed judgment on known or potential impacts from AFOs. Rank order from high to low importance is major, significant, minor, and insignificant. While AFOs may not play an important role for some of these, emissions from other sources alone or in aggregate may have different rankings. For example VOCs and NOx play important roles in the formation of tropospheric ozone; however the role of AFOs is likely to be insignificant compared to other sources.
bVolatile organic compounds.
cParticulate matter. PM10 and PM2.5 include particles with aerodynamic equivalent diameters up to 10 and 2.5 μm, respectively.
aggregate emissions. In some geographic regions, aggregate emission goals may limit the number of animals produced in those regions.
For air emissions important on a local scale (H2S, particulate matter, and odor), the aim is to control ambient concentrations at the farm boundary and/or nearest occupied dwelling. Standards applicable to the farm boundary and/or nearest occupied dwelling must be developed.
Monitoring should be conducted to measure concentrations of air pollutants with possible health concern at times when they are likely to be highest and in places where the densities of animals and humans, and typical meteorological conditions, are likely to result in the highest degree of human exposure.
FINDING 4. There is a general paucity of credible scientific information on the effects of mitigation technology on concentrations, rates, and fates of air emissions from AFOs. However, the implementation of technically and economically feasible management practices (e.g., manure incorporation into soil) designed to decrease emissions should not be delayed.