Measurements of Ammonia at Blodgett Forest

Fischer, Marc L. ; Littlejohn, David

关键词: 54;    AERODYNAMICS;    AEROSOLS;    AGRICULTURE;    AIR QUALITY;    AMMONIA;    ANIMALS;    DEPOSITION;    FORESTS;    HYPOTHESIS;    MIXING RATIO;    PARTICULATES;    PLANTS;    TRANSPORT;    VELOCITY;    VISIBILITY;   

DOI  :  10.2172/922828
RP-ID  :  LBNL--62883
PID  :  OSTI ID: 922828
Others  :  R&D Project: 366083
Others  :  TRN: US200811%%179

美国|英语

来源: SciTech Connect

【 摘 要 】

Ammonia is a reactive trace gas that is emitted in large quantities by animal agriculture and other sources in California, which subsequently forms aerosol particulate matter, potentially affecting visibility, climate, and human health. We performed initial measurements of NH{sub 3} at the Blodgett Forest Research Station (BFRS) during a 3 week study in June, 2006. The site is used for ongoing air quality research and is a relatively low-background site in the foothills of the Sierra Nevada. Measured NH{sub 3} mixing ratios were quite low (< 1 to {approx}2 ppb), contrasting with typical conditions in many parts of the Central Valley. Eddy covariance measurements showed NH{sub 3} fluxes that scaled with measured NH{sub 3} mixing ratio and calculated aerodynamic deposition velocity, suggesting dry deposition is a significant loss mechanism for atmospheric NH{sub 3} at BFRS. A simple model of NH{sub 3} transport to the site supports the hypothesis that NH{sub 3} is transported from the Valley to BFRS, but deposits on vegetation during the summer. Further work is necessary to determine whether the results obtained in this study can be generalized to other seasons.