title: Inorganic PM2.5 at a U.S. agricultural site.
abstract: In this study, we present approximately two years (January 1999-December 2000) of atmospheric NH3, NH4+, HCl, Cl-, HNO3, NO3-, SO2, and SO4= concentrations measured by the annular denuder/filter pack method at an agricultural site in eastern North Carolina. This site is influenced by high NH3 emissions from animal production and fertilizer use in the surrounding area and neighboring counties. The two-year mean NH3 concentration is 5.6 (+/-5.13) microg m(-3). The mean concentration of total inorganic PM2.5, which includes SO4=, NO3-, NH4+, and Cl-, is 8.0 (+/-5.84) microg m(-3). SO4=, NO3-, NH4+, and Cl- represent, respectively, 53, 24, 22, and 1% of measured inorganic PM2.5. NH3 contributes 72% of total NH3 + NH4+, on an average. Equilibrium modeling of the gas+aerosol NH3/H2SO4/HNO3 system shows that inorganic PM2.5 is more sensitive to reductions in gas + aerosol concentrations of sulfate and nitrate relative to NH3.
authors.affiliation: U.S. Environmental Protection Agency, National Risk Management Research Laboratory, Air Pollution Prevention and Control Division, Mail Drop E305-02, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711, USA. walker.johnt@epamail.epa.gov
authors.forename: John T
authors.initials: JT
authors.lastname: Walker
authors.forename: Wayne P
authors.initials: WP
authors.lastname: Robarge
authors.forename: Arun
authors.initials: A
authors.lastname: Shendrikar
authors.forename: Hoke
authors.initials: H
authors.lastname: Kimball
mesh_terms: D000383:Agriculture; D000393:Air Pollutants / Q000032:analysis*; D000641:Ammonia / Q000032:analysis; D000818:Animals; D002712:Chlorides / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D005308:Fertilizers; D006801:Humans; D006851:Hydrochloric Acid / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D017942:Nitric Acid / Q000032:analysis; D009573:Nitrites / Q000032:analysis; D009657:North Carolina; D013458:Sulfur Dioxide / Q000032:analysis
chemical_list: D000393:Air Pollutants; D002712:Chlorides; D005308:Fertilizers; D009566:Nitrates; D009573:Nitrites; D013458:Sulfur Dioxide; D017942:Nitric Acid; D000641:Ammonia; D006851:Hydrochloric Acid