基于正交试验的臭氧及其前体物的非线性响应及控制方案

Nonlinear Response Characteristics and Control Scheme for Ozone and Its Precursors Based on Orthogonal Experimental Methods

臭氧浓度与其前体物排放在不同地区、不同时刻具有高度非线性关系,如何精准防控臭氧污染成为了目前研究的难点.本文基于WRF-Chem空气质量模式和自建的乌海市2018年大气污染物排放清单,以2018年8月17~20日乌海市海勃湾市区的一次臭氧污染过程为例,利用有交互作用的正交试验研究臭氧及其前体物之间的非线性响应,揭示臭氧生成敏感性并确定最优控制方案.结果表明,NO_(x)、VOCs与CO的交互作用、CO、排放的污染物和气象场的交互作用是影响海勃湾市区臭氧浓度的主要因素,在臭氧超标日的12:00~18:00臭氧生成对NO_(x)排放量最为敏感,当NO_(x)、VOCs和CO协同削减60%、30%和30%时,臭氧平均浓度下降最为显著,为12.6μg·m^(-3)(7.8%);通过对化学反应机制分析得出,VOCs和CO通过与·OH和HO2·等自由基反应进而影响整个光化学反应,是导致VOCs与CO对臭氧生成存在显著交互作用的原因.该方法为研究臭氧及其前体物的非线性响应和制定臭氧污染控制方案提供了一种新的思路.

There is a highly nonlinear relationship between ozone concentrations and its precursor emissions in different regions and at different times,which makes developing effective prevention and control measures difficult.An orthogonal experimental method was introduced to assess the influence of ozone precursors and their interactions on ozone formation,clarify the sensitivity of ozone generation,and propose an optimal control scheme.Based on the WRF-Chem air quality model and an emission inventory of air pollutants in Wuhai City in 2018,this study used an ozone pollution event in the Haibowan urban area(August 17 to 202018)to investigate the nonlinear response of ozone formation to its precursors.The orthogonal experiment shows that NO_(x),VOCs interactions with CO,CO,and interactions between pollutants and meteorological factors are the main factors affects ozone concentrations in the Haibowan urban area.Ozone generation was most sensitive to NO_(x)concentrations during the hours 12:00-18:00 when standard values were exceeded.The ozone concentrations decreased significantly by 12.6μg·m^(-3)(7.8%)as NO_(x),VOCs,and CO were reduced by60%,30%,and 30%,respectively.Through the analysis of chemical reaction mechanisms,it is concluded that VOCs and CO affect the photochemical reaction by reacting with·OH,HO2·and other free radicals,which causes the significant interaction between VOCs and CO in the generation of ozone.This method provides a new approach for researching the nonlinear response of ozone formation to its precursors and for proposing ozone pollution control schemes.