Occurrence of gas phase ammonia in the area of Beijing (China) A. Ianniello1, F. Spataro1, G. Esposito1, I. Allegrini1, E. Rantica1, M. P. Ancora1, M. Hu2, and T. Zhu2 1CNR – Institute of Atmospheric Pollution Research, Via Salaria Km 29.3, CP10, 00015 Monterotondo S., Rome, Italy 2State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China
Abstract. The atmospheric concentrations of gaseous ammonia have been measured during
two field campaigns in the winter and in the summer of 2007 at Beijing
(China). These measurements were carried out by means of diffusion annular
denuders coated with phosphorous acid. The results were discussed from the
standpoint of temporal and diurnal variations and meteorological effects.
The daily average NH3 concentrations were in the range of 0.20–44.38 μg/m3
and showed regular temporal variations with higher
concentrations during summer and with lower during winter. The temporal
trends seemed to be largely affected by air temperature because of
agricultural sources. No diurnal variability was observed for gaseous
NH3 levels in both winter and summer seasons. The highest ammonia value
of 105.67 μg/m3 was measured in the early morning during the
summer period when stable atmospheric conditions occurred. The diurnal
winter and summer trends of ammonia showed a weak dependence on the air
temperature and they were affected nearly by wind direction suggesting
regional and local source influences. Ammonia was also correlated with the
atmospheric mixing in the boundary layer, and, with NOx, CO and
PM2.5 air concentrations supporting the hypothesis that the traffic may
be also an important source of ammonia in Beijing.
Citation: Ianniello, A., Spataro, F., Esposito, G., Allegrini, I., Rantica, E., Ancora, M. P., Hu, M., and Zhu, T.: Occurrence of gas phase ammonia in the area of Beijing (China), Atmos. Chem. Phys., 10, 9487-9503, doi:10.5194/acp-10-9487-2010, 2010.