江苏省春季臭氧污染特征分析

对2018—2020年春季江苏省臭氧(O 3)污染特征进行了分析。结果表明,江苏省ρ(O 3)均超过二级标准限值,分别超出5.6%,11.3%和8.8%,沿江区域ρ(O 3)略高于苏北区域;ρ(O 3-1 h)日变化呈“单峰型”,峰值呈逐年上升趋势,非污染日苏北区域ρ(O 3-1 h)均高于沿江区域,主要时间段体现在夜间至次日早晨,污染日中午至傍晚时段,沿江区域ρ(O 3-1 h)高于苏北区域;日ρ(O 3)高频区间为80~120μg/m 3,频率约为20%,沿江区域高频区间为60~120μg/m 3,苏北区域高频区间为80~140μg/m 3,频率均超过15%。沿江和苏北区域日ρ(O 3)在临界区间的出现频率偏差不大,O 3污染潜在风险相当;江苏省ρ(O 3)超标率呈逐年递增趋势,超标现象主要集中在4—5月;O 3作为首要污染物且超标的占比逐年升高,而PM 2.5作为首要污染物且超标的占比逐年降低,江苏省春季空气质量影响因子逐渐从PM 2.5转为O 3;平均>90%的O 3污染日为轻度污染,受O 3影响空气质量达到中度污染的占比较小,平均<10%,未出现因O 3导致的重度或严重污染日。

Study on Characteristics of Ozone Pollution in Jiangsu Province in Spring

The ozone(O 3)pollution characteristic of Jiangsu Province in the spring of 2018—2020 was analyzed.The results showed that the concentration of O 3 in Jiangsu Province exceeded the secondary standard limit of China,exceeding by 5.6%,11.3%and 8.8%respectively.In the area along the Yangtze River,the concentration of O 3 was slightly higher than that in Northern Jiangsu.The daily variation of O 3-1h was"unimodal",the peak value increased year by year,the concentration of O 3-1h in Northern Jiangsu was higher than that in the area along the Yangtze River on the non pollution days,which occured during the period from night to the next morning,while on pollution days from noon to evening,the concentration of O 3-1h in the area along the Yangtze River was higher than that in Northern Jiangsu.The daily concentration of O 3 showed a probability of 20%to fall within the range of 80~120μg/m 3.While the range was 60~120μg/m 3 for the area along the Yangtze River and 80~140μg/m 3 for Northern Jiangsu,both showed the probability of not less than 15%.The difference of daily concentration of O 3 between the area along the Yangtze River and Northern Jiangsu was not obvious,indicating an equivalent potential risk of O 3 pollution in both areas.The probability of O 3 exceeding the set standard increased year by year in Jiangsu province,and excess mainly happened from April to May.The proportion of O 3 as the primary pollutant exceeding the set standard increased year by year,while the proportion of PM 2.5 as the primary pollutant exceeding the set standard decreased year by year,so the influencing factor of spring air quality in Jiangsu province gradually changed from PM 2.5 to O 3,on average,more than 90%of O 3 pollution days were light pollution,less than 10%were moderate pollution,and no heavy or severe pollution days affected by O 3.