乌鲁木齐市环境空气PM_(2.5)与O_(3)协同作用的污染特征分析

Pollution characteristics analysis of the relationship of atmospheric PM_(2.5) and O_(3) in Urumqi

统计分析2013—2021年乌鲁木齐市环境监测资料,研究乌鲁木齐市PM_(2.5)和O_(3)的相关性,以及气象条件对PM_(2.5)和O_(3)相互作用机制的季节变化影响特征。研究结果显示:夏季PM_(2.5)和O_(3)浓度的相关系数为-0.34186,呈负相关性;冬季PM_(2.5)和O_(3)浓度的相关系数为-0.3883,呈负相关性,二者相互作用的季节变化一致性特征呈现相反趋势,这点和PM_(2.5)-O_(3)复合污染的特征明显不同,由此初步判断乌鲁木齐市还处于单PM_(2.5)污染阶段,未处于PM_(2.5)-O_(3)复合污染阶段,但O_(3)浓度连续多年快速上升。夏季光照条件良好,太阳辐射强,气温较高,大气氧化性较弱,O_(3)浓度升高,但PM_(2.5)浓度处于较低水平,说明O_(3)主导的氧化作用导致二次粒子增加的贡献不大;冬季因太阳高度角变化,导致太阳辐射较弱,加上气温较低,大气氧化性较弱,高浓度PM_(2.5)可以削弱太阳辐射,抑制大气光化学反应,导致O_(3)浓度降低,所以冬季PM_(2.5)对O_(3)的抑制作用对大气复合污染变化起着主导作用。

The correlation of PM_(2.5) and O_(3) and the seasonal changes of meteorological conditions on the interaction mechanism of PM_(2.5) and O_(3) were analyzed through environmental monitoring data of Urumqi from 2013 to 2021.The results showed that the correlation coefficient of PM_(2.5) and O_(3) concentration in summer is-0.34186,and in winter is-0.3883,showing the seasonal consistency of the interaction,which is obviously different from the characteristics of PM_(2.5)-O_(3) compound pollution.Therefore,Urumqi is still in the single PM_(2.5) pollution stage,not in the PM_(2.5)-O_(3) compound pollution stage,but the O_(3) concentration has risen rapidly for many years.The concentration of O_(3) increases and the concentration of PM_(2.5) at a low level when in summer,which the light conditions are good,the solar radiation is strong,high temperature and atmospheric oxidation is weak.It's indicating that O_(3) leading oxidation contributes little to the increase of secondary particles.In winter,the solar radiation is weak due to the change of solar altitude angle.In addition,the air temperature is low and the oxidization of the atmosphere is weak.High concentration of PM_(2.5) can weaken the solar radiation and inhibit the photochemical reaction of the atmosphere,leading to the reduction of O_(3) concentration.Therefore,the inhibitory effect of PM_(2.5) on O_(3) in winter plays a leading role in the change of atmospheric composite pollution.