December 2011 Articles

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Air Quality and the Broiler Industry

Air Quality and the Broiler Industry
Theresia Lavergne, Ph.D., P.A.S.
Associate Professor, LSU AgCenter
Public concern for air quality issues linked to poultry and livestock production has increased over the last 15 to 20 years. Air quality regulations are being imposed despite the lack of baseline air emissions data, as well as the lack of reliable methods for estimating air emissions from poultry and livestock operations. Over the past ten years, agricultural engineers and animal scientists have been working to evaluate air emissions and to decrease air pollution from animal feeding operations.
In the broiler industry, ammonia and particulate matter (minute airborne liquid or solid particles) have been the primary air quality concerns. The database on ammonia emissions has been developing over the past years but the database on particulate matter is more limited. Scientists do know that ammonia and particulate matter concentrations vary throughout the day and the variation is greater during cool weather. The variation in ventilation rate plays a big role in the emissions rate from broiler houses. As the indoor temperature affects ventilation rate, the rate of emissions is affected. Thus, as ventilation rate is increased in response to supplemental heating – the rate of emission is increased and varies throughout the day.
Current research reports that ammonia emissions are in the range of 30.9 to 61.7 grams of ammonia per bird marketed for birds grown on built-up litter in the U.S. A researcher at the University of Georgia measured and reported the concentration of ammonia downwind from tunnel-ventilated broiler houses. The report indicated that ammonia concentrations are less than 1 ppm at a distance of 500 feet from the exhaust fans, which is 94% less than the concentration of ammonia at the exhaust fans. Data on particulate matter and greenhouse gases are still limited.
Additionally, when we consider emissions from broiler production, we must think about the emissions from manure storage and land application of manure. Information on these emissions is still limited due to difficulty in quantifying these emissions, as well as the variation in application methods and conditions.
The bright side of this issue is that researchers and the broiler industry do have technology in place to decrease emissions from broiler houses. Dietary manipulations, the use of litter treatments, electrostatic precipitation, biofilters or wet scrubbers, or vegetative buffers can be used to minimize the emissions from broiler houses. Also, when land applying litter, it can be incorporated into the soil to minimize emissions. The economics of some of these technologies are still being evaluated.
The poultry and livestock industries are using the above mitigation strategies to comply with existing air quality regulations, as well as to meet new regulations. The goal of the industries is to use “science-based” technology and information to proactively protect the environment! (Air Issues Associated with Animal Agriculture: A North American Perspective, CAST Issue Paper No. 47, 5/ 2011)