大气中PAN的测定及其与前体物的关系

对北京中关村地区大气ＰＡＮ的监测结果表明：在强日照条件下，ＰＡＮ浓度随汽车等排放和ＮＯ２浓度的增加而增加，高ＰＡＮ浓度水平与高Ｏ３浓度相关联；夏季的ＰＡＮ浓度明显高于春季。模拟实验的结果证实：Ｃ３Ｈ６是大气中重要的ＰＡＮ前体物，在一定范围内，其浓度越高，ＰＡＮ浓度越大；Ｃ２Ｈ４生成ＰＡＮ是困难的，Ｈ２Ｏ２的存在对Ｃ２Ｈ４反应生成ＰＡＮ有促进作用；大气中ＳＯ２的存在可降低ＰＡＮ的生成速率。在〈４００

ATMOSPHERIC PAN MEASUREMENTS AND THE FORMATION OF PAN IN VARIOUS SYSTEMS

PAN(peroxyaoetyl nitrate)was prepared by Gaffneys method for calibration of gas chromatograph used for ambient air monitoring as determined by Fourier Transform Infrared spectrosoopy. Concentrations of PAN in atmosphere were measured in Haidian region of Beijing, China, during March 20-June 12, 1990. The observed range of gaseous PAN concentration was 1.3-6.8 ppbv. High values of gaseous PAN were determined in summer, whereas the lower in spring. The concentration of PAN are generally associated with NOz and O3 under high SR. From diurnal variations of PAN, the maximum value up to 6.8ppbv was recorded at time 12:00-14:00 on June 9, 1990, and the minimum was less than 1 ppbv during night. Indoor smog chamber experiments were conducted to assess the productions of PAN from several systems. The results are shown as follows: in propene-NOx-dry air systems, the peik concentration of PAN depends mainly upon the initial concentration of hydrocarbonHC]0. High content of SO2 in the systems was strongly associated with low PAN concentration. In ethylene-NOx-dry air systems, PAN takes approximately hours of time to reach the maximum and then maintains at low level. The formation of PAN can be promoted in the presence of H2O2.