Studies on gradient observation of O3 and NOx in an atmospheric photochemical pollution
一次光化学污染过程中O3和NOx的垂直梯度观测研究

In order to study atmospheric pollution concentration changes during the 2008 Olympic Games in Beijing, atmospheric pollutants( NO_2 and O_3) at 3 altitude levels of Beijing meteorological tower were observed, and their variations were analyzed. The results indicate that by the strict measures for improving the air quality before Olympic Games, NO_2 concentration reduced by 45. 3% and decreased gradually with the increasing height; both the maximum of O_3 concentrations and the daily average O_3 concentrations decreased. The appear-ance time of O_3 maximum concentration was brought forward about 1～2 h than 10 years ago, and kept stably a-round 4 h. The O_3 peak concentrations were mainly influenced by NO_2. The O_3 concentration peak appeared a-head of schedule,which showed that Beijing atmospheric oxidation efficiency continued to increase. According to the analysis meteorological data and atmospheric pollution monitoring data the meteorological factors for photo-chemical pollution event were found as follows: weak-rield control of high-voltage, stable atmospheric stratifica-tion, weaker wind force ( the wind velocity was less than 2 m/s) , and accompanied by a continuous high temper-ature, strong radiation and low humidity.