北京秋冬季大气氨观测研究

The observation of atmospheric ammonia in Beijing during autumn and winter

利用差分光学吸收光谱技术,对北京市北郊的大气氨进行了近2个月的观测.结果显示,在秋冬季节,北京大气氨的浓度为(12.89±10.12)×10^(-9)(part per billion),观测期间的小时浓度最大值为49.71×10^(-9).氨浓度的日变化呈现出白天低、夜晚高的特征,在早高峰时间,氨有明显的一个峰值浓度.另外,氨与NO_(2)、CO、PM_(2.5)和PM_(10)之间相关性分别为0.845、0.824、0.821和0.598,明显高于春季,说明秋冬季北京大气氨受机动车排放影响明显.气象要素对氨浓度明显影响,风速、气压和相对湿度与氨的关联性较高,相比而言,氨与气温关联性较低,说明秋冬季低温环境下,土壤排放、垃圾存储堆场和人体排泄物等排放对大气氨浓度影响较小.

Differential optical absorption spectroscopy technique was applied to observe the atmospheric ammonia in the northern suburbs of Beijing for nearly two months.The hourly concentration of atmospheric ammonia is averaged for(12.89±10.12)×10^(-9),and peaked at 49.71×10^(-9)for the maximum during the observation period of autumn-winter seasons in Beijing.The diurnal pattern shows ammonia concentration was lower in the daytime and higher at night.An obvious peak of the ammonia concentration occurred in the morning rush hours.The correlations between ammonia and NO_(2),CO,PM_(2.5),PM_(10)are 0.845,0.824,0.821 and 0.598,respectively,which are significantly higher than those in spring.This means the atmospheric ammonia is obviously affected by vehicle emissions in autumn and winter in Beijing.Meteorological factors strongly impact the ammonia concentration,among which wind speed,air pressure and relative humidity show higher correlation with ammonia contrasted to temperature.It suggests that soil emission,waste storage yard and human excreta have less influence on atmospheric ammonia concentration under the condition of low temperature during autumn and winter.