Ammonia and Hydrogen Sulphide Emissions from Swine Production Facilities in North America: a Meta-Analysis25 April 2014
Average emissions rates from pig houses were 2.78 and 0.09kg per pig and year for ammonia and hydrogen sulphide, respectively, according to a literature review by Kansas State University researchers, reported at the 2013 Kansas Swine Industry Day.
Ammonia (NH3) and hydrogen sulphide (H2S) emissions from swine production facilities receive considerable attention due to human health and environmental implications, according to Z. Liu and W.J. Powers. they add that accurate quantification of farm emissions is essential to ensure compliance with regulatory requirements.
The objectives of their study were to provide a review of the literature on ammonia and hydrogen sulphide emissions from swine production facilities in North America with a meta-analysis that integrates results of independent studies, including measured emissions data from both swine houses and manure storage facilities as well as concentration data in the vicinity of swine production facilities.
Results from more than 80 studies were identified through a thorough literature search, and the data were compiled together with results from the 11 swine sites in the National Air Emissions Monitoring Study (NAEMS). Data across studies were analysed statistically using the MIXED procedures of SAS.
Median emissions rates from swine houses were 2.78 and 0.09kg per pig and year for ammonia and hydrogen sulphide, respectively.
Median emissions rates from swine storage facilities were 2.08 and 0.20kg per pig and year for ammonia and hydrogen sulphide, respectively.
The Emergency Planning and Community Right-to-Know Act (EPCRA) require reporting of ammonia and hydrogen sulphide emissions that exceed 100 lb per day.
The size that may trigger the need for a farm to report ammonia emissions is 3,410 pigs, based on median ammonia emissions rates in the literature but the threshold can be as low as 992 pigs based on 90th-percentile emissions rates.
Hoop houses had significantly higher ammonia emission rates than other manure-handling systems (P<0.01), whereas deep pit houses had the highest hydrogen sulphide emission rates (P=0.03).
Farrowing houses had the highest hydrogen sulphide emission rates, followed by gestation houses, and finishing houses had lowest hydrogen sulphide emission rates (P<0.01).
Regression models for ammonia and hydrogen sulphide emission rates were developed for finishing houses with deep pits, recharge pits and lagoons.
The ammonia emission rates increased with increasing air temperature but effects of air temperature on hydrogen sulphide emission rates were not significant. The recharge interval of manure pits significantly affected hydrogen sulphide but not ammonia emission rates. The hydrogen sulphide emission rates were also influenced by the size of the operation.
Although ammonia and hydrogen sulphide concentrations at the edge of swine houses or lagoons were often higher than corresponding acute or intermediate minimum risk levels (MRLs), they decreased quickly to be less than corresponding chronic or intermediate MRLs as distances from emission sources increase.
At distances 30 to 1,185 metres from emission sources, the average ambient concentrations for ammonia and hydrogen sulphide were 66±66ppb and 3.1±6.2ppb, respectively, according to Liu and Powers.
Liu Z. and W.J. Powers. 2013. Ammonia and hydrogen sulfide emissions from swine production facilities in North America: a meta-analysis. Proceedings of 2013 Kansas Swine Day, p256-266.