夏季北京市大气中PAN与PPN的监测分析

采用在线监测仪器,在2005-08对北京市中关村地区大气中的PAN和PPN浓度进行了监测.结果表明,大气中存在着高浓度的PAN和PPN,其最高体积分数分别为2 493.2×10^-12和509.2×10^-12;PPN与PAN的浓度相关性很强,相关系数R²=0.949 5;［PPN］/［PAN］为20.2%. PAN和PPN的浓度在夜间有1个峰值出现,白天高浓度的PAN和PPN出现在NO₂浓度较高而NO浓度较低的时段,PAN与O₃的浓度变化趋势基本一致并显示出一定的相关性.

Monitoring and Analysis of PAN and PPN in the Air of Beijing During the Summer of 2005

PAN and PPN in the urban air of Beijing were monitored by using a online instrument from Aug.15th to Aug.28th, 2005. The results show that the concentrations of PAN and PPN are extremely high in the air of the city area of Beijing, the highest concentrations of PAN and PPN during the daytime are 2493.2×10-12 and 509.2 ×10-12 respectively. A strong correlation was found between PAN and PPN, R2=0.9495, and the average ratio of PPN]/PAN] is about 20.2%, which suggests anthropogenic VOCs are dominant when compared to biogenic ones in the urban air. The precipitation has strong negative effects on the formation and accumulation of PAN and PPN. High concentrations of PAN and PPN occur every midnight. During day time, high concentrations of PAN and PPN occurred with high concentrations of NO2 when NO concentrations are fairly low. Diurnal variations of O3 and PAN are very similar to each other, and a correlation has been indicated between PAN and O3.