摘要
为掌握新冠肺炎疫情爆发前后南京市城区细大气细颗粒物(PM_(2.5))中有机碳(OC)和元素碳(EC)的浓度变化特征,于2020年1—2月期间在南京市主城区在线监测了PM_(2.5)、OC、EC浓度及气象要素。与应急响应前相比,应急响应启动后PM_(2.5)浓度下降了41.2%,EC浓度下降了57.9%,而OC浓度不降反增,表明停工停产显著降低了PM_(2.5)和EC浓度,但对OC浓度变化影响较小。在应急响应前,OC和EC浓度均呈现白天浓度低、清晨及傍晚浓度高的日变化规律;在应急响应后,EC浓度日变化不大且维持在较低水平,OC浓度呈现午后浓度低、午前和傍晚浓度高的变化规律。PM_(2.5)浓度在应急响应后的大幅减少导致光照辐射强度提升,有利于光化学反应生成二次有机碳(SOC)。在PM_(2.5)和EC浓度下降的形势下SOC浓度不降反增,同时OC与EC的相关性显著降低。
In order to explore the variations of carbon components[including organic carbon(OC)and element carbon(EC)]in PM_(2.5) at the urban area of Nanjing during the breakout of COVID-19 period,PM_(2.5),OC and EC mass concentrations were measured by online monitoring from January to February 2020.Compared to the concentrations before the emergency response,the PM_(2.5) concentration after the emergency response was reduced by 41.2%and EC reduced by 57.9%.These results indicate that the shutdown significantly reduced PM_(2.5) and EC concentrations,but the OC concentration increased.Before the emergency response,the OC and EC concentrations were low in daytime and high at night and early morning.After the emergency response,the average concentration of EC only had a slight change within a day and maintained at low concentration level,OC showed a curve trend which was higher in the afternoon and lower in morning and evening.The significant decrease of PM_(2.5) concentration after the emergency response period led to the increasing of light radiation intensity,which promoted the formation of secondary organic carbon(SOC).The SOC concentration increased when the PM_(2.5) and EC concentrations decreased,and the correlation between OC and EC also decreased significantly.
作者
纪源
赵秋月
陈凤
陈东
JI Yuan;ZHAO Qiu-yue;CHEN Feng;CHEN Dong(School of Atmospheric Physics,Nanjing University of Information Science and Technology,Nanjing 210044,China;Jiangsu Key Laboratory of Environmental Engineering,Jiangsu Provincial Academy of Environmental Science,Nanjing 210036,China)
出处
《生态与农村环境学报》
CAS
CSCD
北大核心
2021年第8期992-1000,共9页
Journal of Ecology and Rural Environment
基金
国家重点研发计划(2018YFC0213803)
江苏省PM_(2.5)与臭氧污染协同控制重大专项(2019023)。
