Air Emissions During the Land Application of Manure: a Field Study In Northern New York.

Bioaerosol, particulate matter, and ammonia samples were taken during the land application of dairy manure in northern New York.  Bioaerosol sampling at edge of field included liquid impingers, open-face filters, and size-segregating cascade impactors for quantitative genetic analysis by real-time polymerase chain reaction to assess populations of general bacteria and fecal indicator species.  Simultaneous measurements by 6-stage Anderson impactors were used to assess cultivable bacteria and fungi, and ambient particle concentrations were measured in four size bins.  Fluxes of ammonia from manure amended soil were measured using an isolation flux chamber, and deposition of both bacterial targets and ammonia quantified using surrogate surface and static water surface samplers.  Three application types, including conventional broadcast, low-height broadcast (drag hose), and direct injection, were compared.  Preliminary data suggest little elevation of particulate matter and bacterial targets above background, with low concentrations of fecal indicator species near method detection limits.  Additional genetic analysis is anticipated to assess bacterial pathogens, antibiotic resistance genes, and host-specific molecular biomarkers used to exclude potential sources of fecal pollution.  Ammonia emissions were greatest for broadcast application, with lowest fluxes following subsurface injection.  Final results will be valuable in assessing the air quality implications of manure management, including pathogen transport and emissions of trace gases.