Major ionic compositions of fine particulate matter in an animal feeding operation facility and its vicinity

Abstract

Animal feeding operations (AFOs) produce particulate matter (PM) and gaseous pollutants. Investigation of the chemical composition of PM_2.5 inside and in the local vicinity of AFOs can help to understand the impact of the AFO emissions on ambient secondary PM formation. This study was conducted on a commercial egg production farm in North Carolina. Samples of PM_2.5 were collected from five stations, with one located in an egg production house and the other four located in the vicinity of the farm along four wind directions. The major ions of NH₄⁺, Na⁺, K⁺, SO₄²⁻, Cl⁻, and NO₃⁻ were analyzed using ion chromatography (IC). In the house, the mostly abundant ions were SO₄²⁻, Cl⁻, and K⁺. At ambient stations, SO₄²⁻, and NH₄⁺ were the two most abundant ions. In the house, NH₄⁺, SO₄²⁻, and NO₃⁻ accounted for only 10% of the PM_2.5 mass; at ambient locations, NH₄⁺, SO₄²⁻, and NO₃⁻ accounted for 36–41% of the PM_2.5 mass. In the house, NH₄⁺ had small seasonal variations indicating that gas-phase NH₃ was not the only major force driving its gas–particle partitioning. At the ambient stations, NH₄⁺ had the highest concentrations in summer. In the house, K⁺, Na⁺, and Cl⁻ were highly correlated with each other. In ambient locations, SO₄²⁻ and NH₄⁺ had a strong correlation, whereas in the house, SO₄²⁻ and NH₄⁺ had a very weak correlation. Ambient temperature and solar radiation were positively correlated with NH₄⁺ and SO₄²⁻. This study suggests that secondary PM formation inside the animal house was not an important source of PM_2.5. In the vicinity, NH₃ emissions had greater impact on PM_2.5 formation.

Implications

The chemical composition of PM_2.5 inside and in the local vicinity of AFOs showed the impact of the AFO emissions on ambient secondary PM_2.5 formation, and the fate and transport of air pollutants associated with AFOs. The results may help to manage in-house animal facility air quality, and to develop regional air quality control strategies and policies, especially in animal agriculture-concentrated areas.

Additional information

Notes on contributors

Qian-Feng Li

Qian-Feng Li is a research associate in the Department of Animal Science, Biosystems and Agricultural Engineering, Michigan State University, East Lansing.

Lingjuan Wang-Li

Lingjuan Wang-Li and Sanjay B. Shah are associate professors in the Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC.

Zifei Liu

Zifei Liu is an assistant professor in the Department of Biological and Agricultural Engineering, Kansas State University, Manhattan, KS.

R.K.M. Jayanty

R.K.M. Jayanty is a senior fellow at RTI International, Research Triangle Park, NC.

Sanjay B. Shah

Lingjuan Wang-Li and Sanjay B. Shah are associate professors in the Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC.

Peter Bloomfield

Peter Bloomfield is a professor in the Department of Statistics, North Carolina State University, Raleigh, NC.