Jia Long, Xu Yong-Fu, Shi Yu-Zhen
State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
Huan Jing Ke Xue. 2011 Feb;32(2):351-61.
A self-made new indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosols has been introduced and characterized. The characterization experiments include the measurements of wall effects for reactive species and the determination of chamber dependent * OH radical sources by CO-NO(x) irradiation experiments. Preliminary ethene-NO(x) and benzene-NO(x) experiments were conducted as well. The results of characterization experiments show that the wall effects for O3 and NO2 in a new reactor are not obvious. Relative humidity has a great effect on the wall losses in the old reactor, especially for O3. In the old reactor, the rate constant for O3 wall losses is obtained to be 1.0 x 10(-5) s(-1) (RH = 5%) and 4.0 x10(-5) s(-1) (RH = 91%), whereas for NO2, it is 1.0 x 10(-6) s(-1) (RH = 5%) and 0.6 x 10(-6) s(-1) (RH = 75%). The value for k(NO2 --> HONO) determined by CO-NO(x) irradiation experiments is (4.2-5.2) x 10(-5) s(-1) and (2.3-2.5) x 10(-5) s(-1) at RH = 5% and RH 75% -77%, respectively. The average *OH concentration is estimated to be (2.1 +/- 0.4) x 10(6) molecules/cm3 by using a reaction rate coefficient of CO and * OH. The sensitivity of chamber dependent auxiliary reactions to the O3 formation is discussed. Results show that NO2 --> HONO has the greatest impact on the O3 formation during the initial stage, N2O5 + H2O --> 2HNO3 has a minus effect to maximum O3 concentration, and that the wall losses of both O3 and NO2 have little impact on the O3 formation. The results from the ethene-NO(x) and benzene-NO(x) experiments are in good agreement with those from the MCM simulation, which reflects that the facility for the study of the formation of secondary pollution of ozone and secondary organic aerosols is reliable. This demonstrates that our facility can be further used in the deep-going study of chemical processes in the atmosphere.
介绍并描述了一种自行搭建的新型室内环境舱设施，用于研究导致臭氧和二次有机气溶胶形成的大气过程。表征实验包括对反应性物种的壁效应测量以及通过CO-NO(x)辐照实验确定舱内依赖的OH自由基源。还进行了初步的乙烯-NO(x)和苯-NO(x)实验。表征实验结果表明，新反应器中O3和NO2的壁效应不明显。相对湿度对旧反应器中的壁损失有很大影响，尤其是对O3。在旧反应器中，O3壁损失的速率常数在RH = 5%时为1.0×10(-5) s(-1)，在RH = 91%时为4.0×10(-5) s(-1)；而对于NO2，在RH = 5%时为1.0×10(-6) s(-1)，在RH = 75%时为0.6×10(-6) s(-1)。通过CO-NO(x)辐照实验确定的k(NO2→HONO)值在RH = 5%时为(4.2 - 5.2)×10(-5) s(-1)，在RH = 75% - 77%时为(2.3 - 2.5)×10(-5) s(-1)。利用CO与OH的反应速率系数估计平均*OH浓度为(2.1±0.4)×10(6)分子/cm3。讨论了舱内依赖的辅助反应对O3形成的敏感性。结果表明，NO2→HONO在初始阶段对O3形成的影响最大，N2O5 + H2O→2HNO3对最大O3浓度有负效应，而O3和NO2的壁损失对O3形成的影响很小。乙烯-NO(x)和苯-NO(x)实验的结果与MCM模拟结果吻合良好，这反映了用于研究臭氧和二次有机气溶胶二次污染形成的设施是可靠的。这表明我们的设施可进一步用于大气化学过程的深入研究。
