The status of atmospheric concentrations of ammonia in an intensive dairy farming area in central Japan

Abstract

(pp. 53–57) Atmospheric concentrations of ammonia were monitored for one year in an intensive dairy farming area and its environs in the Kanto region in central Japan. Passive samplers were used to collect gaseous ammonia in the atmosphere. A clear difference in concentrations was observed: they were high in the central farming area (3.2–36.2 µg N m−3) and low in its surrounding area (0.2–0.4 µg N m−3). Seasonal changes in concentrations were also witnessed · concentration reached a peak in April and May. A negative correlation was found between the annual mean of ammonia concentrations and the distance from the manure facilities of dairy farmers. Ammonia volatilization from manure was considered to be the primary factor that controlled the atmospheric concentrations of ammonia within 1 km of the manure facilities. The annual mean concentrations of ammonia positively correlated with the nitrogen concentrations in open-bulk precipitation. It was, therefore, suggested that ammonia emissions from dairy farming affected the wet deposition of nitrogen. On the other hand, both seasonal changes in precipitation and manure management performed by dairy farmers were considered to be the primary factors that induced seasonal changes in atmospheric ammonia concentrations.