Jun-Ji Cao 1,2, Ting Zhang1, Judith C. Chow3, John G. Watson3, Feng Wu1, Hua Li1
Received:
May 31, 2009
Revised:
May 31, 2009
Accepted:
May 31, 2009
Download Citation:
||https://doi.org/10.4209/aaqr.2008.10.0043
Cite this article:
Cao, J.J., Zhang, T., Chow, J.C., Watson, J.G., Wu, F. and Li, H. (2009). Characterization of Atmospheric Ammonia over Xi’an, China.
Aerosol Air Qual. Res.
9: 277-289. https://doi.org/10.4209/aaqr.2008.10.0043
Continuous measurements of atmospheric ammonia (NH3) between April 2006 and April 2007 were conducted at an urban site and a suburban site in Xi’an, northwest China. NH3 was collected using Ogawa passive samplers every sixth day. At the same time, NH4+ in fine particles was collected using battery-powered mini-volume samplers. The annual average concentrations of NH3 were 12.9 µg/m3 and 14.1 µg/m3, at the urban and suburban sites, respectively. The NH3 concentrations reached a maximum (~22.8-35.3 µg/m3) in June and July and were minimum (~3.0-4.7 µg/m3) in December, which was closely linked with NH3 volatilization under different ambient temperatures. The seasonal variation in NH3 was summer > spring > autumn > winter at both sites, which may be ascribed to the impact of biological emission sources such as agricultural activity. NH3 and NH4+ aerosol concentrations were weakly correlated, implying that gas-particle reactions are influenced by many factors such as sources, meteorology and removal. Average NH3/NH4+
ABSTRACT
Keywords:
NH3; NH4+; Aerosol, Agricultural activity
