摘要
为探究香港冬季气溶胶消光特征以及细颗粒物(PM2.5)的化学组分对消光系数的贡献,本次研究利用2013年1月在香港科技大学站点测定的高时间分辨率大气气溶胶消光系数以及PM2.5化学组分的观测数据重建本地化消光系数与颗粒物化学组分浓度的经验关系式——IMPROVE公式。结果表明,观测期间PM2.5质量浓度与散射系数的日均值分别为(43.31±16.80)µg/m^(3)和(191.57±85.34)Mm^(−1),散射系数与PM2.5质量浓度的相关系数R2达到0.90,对其贡献达到85.81%。散射系数在高污染和低污染阶段均是夜间高于白天,吸收系数主要在低污染阶段表现出夜间高于白天。分别对整个观测期间高污染和低污染阶段重建IMPROVE公式,发现1月的硫酸盐、硝酸盐、海盐和有机物的质量散射效率分别为2.02 m^(2)/g、2.41 m^(2)/g、0.41 m^(2)/g和5.07 m^(2)/g,元素碳和NO2的质量吸收效率分别为15.97 m^(2)/g和0.79 m^(2)/g,而高污染阶段,硝酸盐的质量散射效率(2.51 m^(2)/g)相比于低污染阶段(2.03 m^(2)/g)有明显提高。观测期间,硫酸盐对散射系数的贡献最高((54.34±10.49)%),其次是有机物((27.59±8.04)%),硝酸盐((17.54±6.86)%)和海盐((0.53±0.43)%)。硫酸盐和有机物分别在夜间和白天的贡献较高,硝酸盐在高污染阶段夜间的贡献增加可能与高污染阶段夜间相对湿度的增加以及质量散射效率的增长有关。元素碳在高污染阶段对吸收系数的贡献超过90%,而NO2气体在低污染阶段对吸收系数的贡献达到22.11%。
To investigate the extinction characteristics of aerosols and the contribution of fine particulate matter(PM2.5)chemical composition to the extinction coefficient at a suburban site in Hong Kong in winter,observations of the extinction coefficient of atmospheric aerosol and the chemical composition of PM2.5 were conducted at the Hong Kong University of Science and Technology(HKUST)in January 2013.The results show that the daily mean values of PM2.5 mass concentration and scattering coefficient were(43.31±16.80)µg/m^(3) and(191.57±85.34)Mm^(−1),respectively.The correlation coefficient of the scattering coefficient and PM2.5 mass concentration was 0.90,and the contribution of scattering coefficient to extinction coefficient reached 85.81%.The scattering coefficient was higher at night than during the daytime in both the high-pollution(HP)and low-pollution(LP)stages,and the absorption coefficient was higher at night than in the low-pollution stage.Based on a modified Interagency Monitoring of Protected Visual Environments(IMPROVE)algorithm,the localized mass scattering efficiency for sulfate,nitrate,sea salt,and organic matter in January were 2.02 m2/g,2.41 m^(2)/g,0.41 m^(2)/g,and 5.07 m^(2)/g,respectively.The mass absorption efficiency of elemental carbon and NO2 were 15.97 m^(2)/g and 0.79 m^(2)/g,respectively.We also reconstructed the IMPROVE algorithm in both high-pollution and low-pollution episodes,to investigate the influence of the pollution level.The results suggest the mass scattering efficiency for nitrate in the high-pollution period(2.51 m^(2)/g)was significantly higher than that of the low-pollution period(2.03 m^(2)/g).The contribution of sulfate to the scattering coefficient was the highest((54.34±10.49)%),followed by the contribution of organic matter((27.59±8.04)%),nitrate((17.54±6.86)%),and sea salt((0.53±0.43)%).The average diurnal variation showed that sulfate and organic matter had higher contributions at the nighttime and daytime,respectively.The higher mass scattering efficiency of nitrate and relative humidity might have been responsible for the significant increase in scattering coefficient of nitrate during the high-pollution period.The contribution of elemental carbon to the absorption coefficient in the high-pollution phase exceeded 90%,while the contribution of NO2 gas to the absorption coefficient in the low-pollution phase reached 22.11%.
作者
任丹阳
周杨
吴冠儒
盛立芳
王文彩
郁建珍
REN Dan-yang;ZHOU Yang;WU Guan-ru;SHENG Li-fang;WANG Wen-cai;YU Jian-zhen(College of Oceanic and Atmospheric Sciences,Ocean University of China,Qingdao 266100,China;Institute of Environment,Hong Kong University of Science and Technology,Hong Kong 999077,China;Department of Chemistry,Hong Kong University of Science and Technology,Hong Kong 999077,China)
出处
《地球化学》
CAS
CSCD
北大核心
2021年第1期12-21,共10页
Geochimica
基金
国家自然科学基金(41605114,41875155)
环境与自然保护基金/惠洛克绿色基金(ECWW09EG04)。
关键词
细颗粒物
消光系数
IMPROVE公式
污染水平
fine particulate matter
extinction coefficient
IMPROVE formula
pollution level
