Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要:
To investigate on the daytime OH and its implication to fine particle, the long-path differential optical absorption spectroscopy (LP-DOAS) system was employed to observe the main OH precursors of O3, HCHO and HONO, as well as NO2and NO3radical from April to August 2013 over Shanghai, China. The main OH production paths from HONO, HCHO and O3were estimated to be occupied around 57.6%, 30.5% and 11.9% during daytime. The daytime OH radical concentration under steady-state was averaged at 1.02ï¿½× 107�molec�cm−3, which was significantly impacted by the photolytic processes. The relationship between photolysis frequency j(O1D) and OH radical suggests that heavy fine particle loads can make the photolytic reactions less efficiently and decrease the OH production and concentration. Utilizing CO as the indicator, the part of PM2.5mass related to primary emitted sources was found less impacted by the OH levels. The contribution of secondary organic aerosol with metrics of O3was enhanced with the increases of the OH levels, while secondary inorganic part of PM2.5was favor of the condition that smaller OH concentrations that 5ï¿½× 105–5ï¿½× 106�molec�cm−3. Meantime, a simplified multivariate model was employed to evaluate the influences of OH levels on different parts of fine particles related to different emission and sources. Normalized by solar radiation, this part of OH unrelated to radiation was found to be inversely related to the PM2.5, which indicates the self-cleansing capability of the atmosphere. � 2017 Elsevier Ltd
Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai, China
Recommended Citation:
Nan J,, Wang S,, Guo Y,et al. Study on the daytime OH radical and implication for its relationship with fine particles over megacity of Shanghai, China[J]. Atmospheric Environment,2017-01-01,154