摘要
气溶胶液态水含量(ALWC)及酸度(pH)是表征气溶胶理化性质的重要指标,对PM_(2.5)二次颗粒生成机制及来源研究具有重要意义.本文基于国家环境保护长三角区域大气复合污染上海淀山湖科学观测研究站2020年PM_(2.5)和水溶性离子组分等在线监测数据,利用ISORROPIA-Ⅱ模型正向模式和亚稳态体系分析了ALWC和pH的昼夜、月度时间变化以及影响因素、相互关系,同时利用MeteoInfo模拟气团后向轨迹探究了高值ALWC及pH的传输来源.结果表明:①SO_(4)^(2-)、NO_(3)^(-)对气溶胶pH的影响与其浓度、比例及ALWC有关,而NH_(4)^(+)对pH的影响有限,NH_(4)^(+)与SO_(4)^(2-)、NO_(3)^(-)浓度均呈较强正相关,且pH越高,NH_(4)^(+)与SO_(4)^(2-)、NO_(3)^(-)浓度越靠近拟合曲线.②PM_(2.5)浓度低于75μg/m3时ALWC较低;在相对湿度高于80%时,随着PM_(2.5)浓度升高,ALWC迅速增加.③ALWC表现为1月最高、8月最低,且一天内午后最高;当温度介于13~27℃时,ALWC受温度影响较小;当温度高于27℃时,随着温度升高,ALWC逐渐降低.④pH表现为冬季高、夏季低,且一天内午后最低,可能是由于温度升高导致ALWC和pH降低.⑤气团的来源、移动速度对ALWC和pH均存在一定程度的影响.研究显示,长三角东部沿海地区气溶胶液态水含量和酸度受气象条件影响显著,温度和相对湿度的变化是判定气溶胶理化性质演变的重要指标.研究结果可为进一步深化对长三角东部沿海地区气溶胶生成机制的认识提供数据和理论参考.
Aerosol liquid water content(ALWC)and acidity(pH)are important indicators to characterize the physical and chemical properties of aerosols,which are of great significance for studying the aerosol generation mechanism and PM_(2.5)pollution sources.This study was based on the online monitoring data of PM_(2.5)and water-soluble ion components from the State Ecology and Environment Scientific Observation and Research Station for the Yangtze River Delta at Dianshan Lake in 2020.The diurnal and monthly time changes of ALWC and pH,their influencing factors,and their relationship were analyzed using the ISORROPIA-Ⅱmodel with positive and metastable system.At the same time,MeteoInfo software was used to simulate the backward trajectory of air masses,and the transmission sources of higher ALWC and pH were explored.The results indicated that:(1)The effects of SO_(4)^(2-)and NO_(3)^(-)on aerosol pH were related to their concentrations,proportions,and ALWC,while the impact of NH_(4)^(+)on pH was limited.NH_(4)^(+)showed a strong positive correlation with SO_(4)^(2-)and NO_(3)^(-),and higher pH tended to approach the fitting curve.(2)ALWC was lower when the concentration of PM_(2.5)was below 75μg/m3.As RH increased with the increase of PM_(2.5)concentration,ALWC rose rapidly,especially when RH exceeded 80%.(3)ALWC was highest in January,lowest in August and highest in the afternoon.When the temperature was between 13-27℃,its sensitivity to temperature was relatively small,but as the temperature increased,ALWC gradually decreased.(4)pH was higher in winter and lower in summer,with the lowest values occurring in the afternoon of the day,possibly because the temperature increase resulted in a decrease in ALWC and a subsequent decrease in pH.(5)The origin and movement speed of air masses had certain influences on both ALWC and pH.The research shows that the liquid water content and acidity of aerosols in the Yangtze River Delta region are significantly affected by meteorological conditions,and changes in temperature and relat
作者
段玉森
赵月
黄凡非
陈佳
霍俊涛
伏晴艳
DUAN Yusen;ZHAO Yue;HUANG Fanfei;CHEN Jia;HUO Juntao;FU Qingyan(Shanghai Environmental Monitoring Center,Shanghai 200235,China;Shanghai Technology Center for Reduction of Pollution and Carbon Emissions,Shanghai 200235,China;Peking University Environment and Energy School,Shenzhen 518055,China)
出处
《环境科学研究》
CAS
CSCD
北大核心
2023年第12期2245-2255,共11页
Research of Environmental Sciences
基金
国家重点研发计划项目(No.2022YFC3703500)
上海市科学技术委员会重点研发计划项目(No.20DZ1204000)。
