Opening Another Chapter: Air Emissions-Particulates

Agriculture in Pennsylvania will be impacted by various air quality and emissions regulations. This article will discuss the Clean Air Act, particulates and ammonia, and their relationship to Animal Feeding Operations (AFOs). Other agricultural operations including field crops, horticultural crops and mushrooms may also be impacted.

The federal Clean Air Act (1997) established the National Ambient Air Quality Standards (NAAQS) for six primary pollutants. They include carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, lead, and particulate matter. Pennsylvania has adopted all of the NAAQS standards as well as several standards of its own. Pennsylvania monitors the principal pollutants to ensure attainment of these standards. The main purpose is to protect public health. Ammonia is not listed as a primary pollutant in this act but is an important precursor to the formation of PM2.5 (particulate matter less than 2.5 micrometers in diameter).

Particulate matter includes both solid and liquid particles suspended in air. Particles less than 2.5 micrometers in diameter are a health concern because they can be inhaled into and accumulate in the respiratory system. PM2.5 can be directly emitted from a source or formed in the air from chemical changes of gases as they react with water vapor, sunlight, and other gases to form PM complexes. Fine particles can be composed of sulfates and nitrates. Ammonia generated from agricultural operations can react with trace gases in the atmosphere to form the aerosols ammonium sulfate and ammonium nitrate, which are the basis for fine particulates. Since PM2.5 is a regulated pollutant and ammonia is a precursor, animal-feeding operations in non-attainment areas may be required to apply for air permits, keep records and report emissions of ammonia and PM2.5. Hydrogen sulfide emissions from AFOs may also be included.

The PM2.5 standards are an annual average of 15 ug/m3 (micrograms per cubic meter) and a 24-hour average of 65 ug/m3. Currently there are several counties located in western and southeastern Pennsylvania that are listed as non-attainment areas. Counties that have exceeded the standard for PM based on PA DEP assessment include Beaver, Allegheny, Washington, Westmoreland, Cambria, Cumberland, Dauphin, York, Lancaster, Berks, Chester, Delaware, and Philadelphia. Based on EPA's recommendations, additional counties are included (Mercer, Lawrence, Butler, Armstrong, Indiana, Greene, Lebanon, Montgomery, and Bucks). Penn State's nutrient management web site http://www.nutrient.psu.edu/ contains links to EPA's more detailed information on fine particle (PM2.5) designations. PA DEP must present a plan for improving air quality in these non-attainment areas. Agricultural operations located in non-attainment areas may be included in remediation plans. The following is a tentative time-line regarding PM2.5 implementation program:

This article has illustrated another way in which Pennsylvania livestock agriculture can become involved in air quality efforts and regulations. Livestock producers can no longer keep thinking that these regulations are not going to affect me. The eye opener is any AFO can potentially be regulated for ammonia, hydrogen sulfide and PM2.5 regardless of their size or location. Now is the time to become involved in the process by letting your legislators, DEP and EPA representatives, and the appropriate agricultural industries know your concerns related to clean air and keeping animal agriculture viable in Pennsylvania. Information on this and other air emission related topics might be found at http://www.nutrient.psu.edu/

Virginia Ishler, Dairy Alliance
and
Robert E. Graves, Agricultural and Biological Engineering Department