A Council for Agricultural Science and Technology study on North American air quality has been released, focusing on the topic as it relates to the areas of swine, poultry, dairy and beef farming.

The goal of "Air Issues Associated with Animal Agriculture: A North American Perspective," according to researchers, is to use science-based information to help all stakeholders involved in animal production protect the environment and public health in a proactive manner and avoid costly litigation to solve nuisance suits or enforce regulations. Historically, environmental concerns and regulations of animal agriculture focused on water quality. In the past 15 to 20 years, however, air quality issues associated with the livestock and poultry industries have become a growing concern for the public, leading to increased attention on enforcing air quality regulations for animal agriculture and new multimedia regulatory efforts.

A few of the study's specific findings, composed from data for odor, hazardous gases, greenhouse gases and pollutant concentrations in animal buildings, include:


  • Diet composition has a significant impact on emissions.
  • Mitigation methods, such as covering the manure storage surface, can greatly decrease odor emissions.
  • Aeration of the storage basin or employing anaerobic digestion of the manure will also reduce the odor, but with higher costs.

Swine production systems generate a large variety of significant air emissions, according to the report. Ammonia, H2S, odor, volatile organic compounds, particulate matter, bioaerosols and greenhouse gases are all emitted in quantities of concern from pork production systems. This has created challenges for pork producers, because a more comprehensive approach (versus targeting one or two contaminants) is necessary to control or manage several of these air emission parameters simultaneously. But the pork industry has been quite progressive in dealing with air quality problems, funding emissions research projects and promoting practices and technologies that manage and mitigate air emissions from their production systems.

Poultry producers, on the other hand, have been concerned primarily with one airborne contaminant — ammonia — secondarily, with particulate matter and, potentially, bioaerosols. This is especially the case for layer operations, according to the report. Meat bird (broiler and turkey) producers have some concern with particulate matter levels in barns and particulate matter emissions because of the litter pack manure-handling systems. Ammonia emissions have been determined for the major housing systems used in the poultry industry, with some housing systems and/or management practices producing substantial NH3 emission decrease.