Thermal internal boundary layer and its effects on air pollutants during summer in a coastal city in North China  

作　　者：Jie Wei Guiqian Tang Xiaowan Zhu Lili Wang Zirui Liu Mengtian Cheng Christoph Münkel Xin Li Yuesi Wang 

机构地区：[1]State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(LAPC),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [2]Center for Excellence in Regional Atmospheric Environment,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen 361021,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]Vaisala GmbH,22607 Hamburg,Germany [5]Beijing Municipal Committee of China Association.for Promoting Democracy,Beijing 100035,China

出　　处：《Journal of Environmental Sciences》2018年第8期37-44,共8页环境科学学报（英文版）

基　　金：supported by the National Key R&D Program of China(No.2017YFC 0210000);the National Natural Science Foundation of China(Nos.41230642 and 41705113);the Beijing Municipal Science and Technology Project(No.ZL171100000617002)

摘　　要：The thermal internal boundary layer（TIBL） is associated with coastal pollution dispersion,which can result in high concentrations of air pollutants near the surface of the Earth. In this study, boundary layer height data which were obtained using a ceilometer were used to assess the effect of the TIBL on atmospheric pollutants in Qinhuangdao, a coastal city in North China.A TIBL formed on 33% of summer days. When a TIBL formed, the sunshine duration was 2.4 hr longer, the wind speed was higher, the wind direction reflected a typical sea breeze, and the boundary layer height was lower from 9：00 LT to 20：00 LT compared to days without a TIBL. If no TIBL formed, the average concentrations of PM2.5 and PM10 decreased with increasing boundary layer height. However, when a TIBL was observed, the average concentrations of PM2.5 and PM10 increased with increasing boundary layer height. Because the air from the sea is clean, PM2.5 and PM10 concentrations reached minimums in the daytime at 16：00 LT. After16：00 LT, the PM2.5 and PM10 concentrations increased rapidly on days when a TIBL formed,which indicated that the TIBL leads to the rapid accumulation of atmospheric pollutants in the evening. Therefore, the maximum concentrations of particulate matters were larger when a TIBL formed compared to when no TIBL was present during the night. These results indicate that it is suitable for outdoor activities in the daytime on days with a TIBL in coastal cities.The thermal internal boundary layer（TIBL） is associated with coastal pollution dispersion,which can result in high concentrations of air pollutants near the surface of the Earth. In this study, boundary layer height data which were obtained using a ceilometer were used to assess the effect of the TIBL on atmospheric pollutants in Qinhuangdao, a coastal city in North China.A TIBL formed on 33% of summer days. When a TIBL formed, the sunshine duration was 2.4 hr longer, the wind speed was higher, the wind direction reflected a typical sea breeze, and the boundary layer height was lower from 9：00 LT to 20：00 LT compared to days without a TIBL. If no TIBL formed, the average concentrations of PM2.5 and PM10 decreased with increasing boundary layer height. However, when a TIBL was observed, the average concentrations of PM2.5 and PM10 increased with increasing boundary layer height. Because the air from the sea is clean, PM2.5 and PM10 concentrations reached minimums in the daytime at 16：00 LT. After16：00 LT, the PM2.5 and PM10 concentrations increased rapidly on days when a TIBL formed,which indicated that the TIBL leads to the rapid accumulation of atmospheric pollutants in the evening. Therefore, the maximum concentrations of particulate matters were larger when a TIBL formed compared to when no TIBL was present during the night. These results indicate that it is suitable for outdoor activities in the daytime on days with a TIBL in coastal cities.

关 键 词：Thermal internal boundary layer CEILOMETER Air pollutants Sea breeze 

分 类 号：Q1[生物学—普通生物学]