中文关键词大气光化学氧化剂(O_x)PM_2.5复合污染天气形势珠江三角洲(PRD) 英文关键词atmospheric photochemical oxidant (O_x)PM_2.5complex pollutionweather situationPearl River Delta (PRD)

作者	单位	E-mail
颜丰华	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443	13557016413@163.com
陈伟华	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443
常鸣	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443
王伟文	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443
刘永林	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443
钟部卿	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443
毛敬英	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443
杨土士	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443
王雪梅	暨南大学环境与气候研究院, 粤港澳环境质量协同创新联合实验室, 广州 510443	eciwxm@jnu.edu.cn
刘婵芳	深圳市环境监测中心站, 深圳 518049	99753846@qq.com

中文摘要 基于粤港澳珠江三角洲区域空气监测网络12个监测子站的大气污染物数据，梳理2013~2017年大气光化学氧化剂O_x（NO₂+O₃）与PM_2.5质量浓度的变化趋势.O_x+PM_2.5复合超标污染定义为NO₂和PM_2.5质量浓度日平均值以及O₃浓度日最大8 h平均值（O₃ MDA8）同时超过二级浓度限值，分析了不同类型站点复合超标污染的时空分布特征以及气象因素影响.结果表明，2013~2017年珠三角PM_2.5年均质量浓度由（44±7）μg·m^-3下降至（32±4）μg·m^-3，实现PM_2.5连续3 a达标.O_x年均质量浓度由2013年（127±14）μg·m^-3下降至2016年（114±12）μg·m^-3，2017年反弹至（129±13）μg·m^-3，O₃浓度上升明显（10 μg·m^-3）.以O₃为首要污染物的污染过程占比由2013年33%增多至2017年78%，多个城市同时发生污染的区域特征明显.研究时段内O_x+PM_2.5复合超标污染事件共发生60次，主要在城区站点（78%）和郊区站点（22%）.秋季发生复合超标污染天数最多（52%），是因为强太阳辐射有利于臭氧生成，大气氧化性增加，进而促进了PM_2.5二次生成.造成珠三角复合超标污染的天气形势主要为高压出海型（43%）、高压控制型（30%）和热带低压型（27%）.就具体气象因素而言，气温在20~25℃且相对湿度在60%~75%的范围内时，复合超标污染事件发生占比最高（22%）.在O₃重污染过程中，夜间高湿和低风速使得NO₂和PM_2.5浓度显著上升，日间高温加剧了复合超标污染. 英文摘要 Based on the atmospheric pollutant data from twelve monitoring sites in the Guangdong-Hong Kong-Macao Pearl River Delta Regional Air Quality Monitoring Network, the mass concentration trends of atmospheric photochemical oxidants (O_x, NO₂+O₃) and PM_2.5 during 2013-2017 were studied. The complex nonattainment pollution of O_x and PM_2.5 is defined as the daily average mass concentration of NO₂ and PM_2.5 and daily maximum 8 h average (O₃ MDA8) mass concentration of O₃ simultaneously that exceeds the Chinese grade Ⅱ national air quality standard. The characteristics and meteorological factors that influence the complex nonattainment pollution of O_x and PM_2.5 at different types of areas were analyzed. The results indicate that from 2013 to 2017, the annual average mass concentration of PM_2.5 in the Pearl River Delta (PRD) region decreased from (44±7) μg·m^-3 to (32±4) μg·m^-3, which met the annual standard for three consecutive years. The annual average mass concentration of O_x decreased from (127±14) μg·m^-3 in 2013 to (114±12) μg·m^-3 in 2016 and then showed a general rebound trend to (129±13) μg·m^-3 in 2017 when O₃ concentrations increased significantly (10 μg·m^-3). The proportion of pollution processes with O₃ as the primary pollutant increased from 33% in 2013 to 78% in 2017, and the regional characteristics of simultaneous pollution in multiple cities have been highlighted. The complex nonattainment pollution of O_x and PM_2.5 occurred 60 times during the study period, primarily in urban sites (78%) and suburban sites (22%). The largest number of days of complex nonattainment pollution occurred in autumn (52%) because of strong solar radiation that was conducive to ozone formation, and consequently, the high oxidization of the atmosphere promoted the secondary generation of PM_2.5. The weather conditions that caused the complex nonattainment pollution in the PRD mainly include outflow-high-pressures (43%), subtropical-high-pressures(30%), and tropical-depressions (27%). In terms of specific meteorological conditions, when the temperature was in the range of 20-25℃ and relative humidity was in the range of 60%-75%, the proportion of complex nonattainment pollution was the highest (22%). When O₃ pollution was substantial, the high relative humidity and low wind speed during the nighttime caused the concentration of NO₂ and PM_2.5 to rise significantly, and then the high temperatures during the day aggravated the complex nonattainment pollution.

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