Recent Developments in the Quantification and Regulation of Air Emissions from Animal Feeding Operations.

Animal feeding operations (AFOs) emit various air pollutants, including ammonia, hydrogen sulfide, particulate matter, volatile organic compounds, methane, and nitrous oxide. Several of these pollutants are regulated under federal clean air statutes, yet AFOs have largely escaped regulation under these laws because of challenges in accurately estimating the rate and quantity of emissions from various types of livestock operations. Recent Environmental Protection Agency (EPA) efforts to collect emissions data, develop an emissions model capable of estimating emissions at AFOs nationwide, and establish emissions estimating methodologies for certain key livestock air pollutants suffered from design flaws and omitted pollutants of concern. Moreover, this process seems to have stalled, delaying other regulatory reforms needed to increase transparency and increase regulation of these facilities. Until EPA establishes these methodologies, significant AFO pollution regulation under the Clean Air Act or emissions reporting statutes will be very difficult to achieve, and the public health and environmental impacts of these emissions will continue unabated.