对流层氮氧化物光化学转化特征研究

应用大气光化学模式研究了日间影响NOx光化学转化率的主要物理化学因子.探讨了在不同NMHC/NOx比值时,NOx光化学特征及其转化产物的变化规律.结果表明,影响NOx转化率的主要因子是阳光辐射强度和NMHC/NOx比值.但在NMHC/NOx比值很低时,光强的增加并不能显著提高NOx转化率.温度和初始臭氧浓度对NOx转化率的影响次之.相对湿度对NOx转化率的影响较小.在不同NMHC/NOx比值下,NOx转化特征和产物有很大区别.NMHC/NOx比值高时,产物中PAN＞HNO3.NMHC/NOx比值中(低)时,产物主要是HNO3,PAN等有机氮不到10%(1%).最后初步比较了模拟和观测的NOy组成.

A Research of Photochemical Transformation of NOx in Troposphere

A study of primary controlling factors of NOX photochemical transformations during the daytime and NOX transformation products were conducted by using an atmospheric photochemical box model. The results show that the most important factors are radiant intensity and NMHC/ NOX ratio, however low NMHC/ NOX ratio, NOX transformation rate cannot increase remarkably with radiant intensity. The effect of temperature and initial ozone level on NOX transformation rate ranks seoonel, and the relative humidity effect is quiet small. Under different NMHC / NOX ratios, the NOX transformation features and products compositions are very different. For higher NMHC/ NOX ratio, the PAN level is higher than HNO3. In middle (lower) NMHC/ NOX ratio, the product is mainly composed of HNO3; however, PAN and other organic nitrogen compound are smaller than 10%(1%) of total NOy. Lastly, the modeling NOy compositions are compared with measurements in some areas.