TY  - JOUR
AU  - Lu, Keding
AU  - Fuchs, Hendrik
AU  - Hofzumahaus, Andreas
AU  - Tan, Zhaofeng
AU  - Wang, Haichao
AU  - Zhang, Lin
AU  - Schmitt, Sebastian H.
AU  - Rohrer, Franz
AU  - Bohn, Birger
AU  - Broch, Sebastian
AU  - Dong, Huabin
AU  - Gkatzelis, Georgios I.
AU  - Hohaus, Thorsten
AU  - Holland, Frank
AU  - Li, Xin
AU  - Liu, Ying
AU  - Liu, Yuhan
AU  - Ma, Xuefei
AU  - Novelli, Anna
AU  - Schlag, Patrick
AU  - Shao, Min
AU  - Wu, Yusheng
AU  - Wu, Zhijun
AU  - Zeng, Limin
AU  - Hu, Min
AU  - Kiendler-Scharr, Astrid
AU  - Wahner, Andreas
AU  - Zhang, Yuanhang
TI  - Fast Photochemistry in Wintertime Haze: Consequences for Pollution Mitigation Strategies
JO  - Environmental science & technology
VL  - 53
IS  - 18
SN  - 1520-5851
CY  - Columbus, Ohio
PB  - American Chemical Society
M1  - FZJ-2019-05746
SP  - 10676 - 10684
PY  - 2019
AB  - In contrast to summer smog, the contribution of photochemistry to the formation of winter haze in northern mid-to-high latitude is generally assumed to be minor due to reduced solar UV and water vapor concentrations. Our comprehensive observations of atmospheric radicals and relevant parameters during several haze events in winter 2016 Beijing, however, reveal surprisingly high hydroxyl radical oxidation rates up to 15 ppbv/h, which is comparable to the high values reported in summer photochemical smog and is two to three times larger than those determined in previous observations during winter in Birmingham (Heard et al. Geophys. Res. Lett. 2004, 31, (18)), Tokyo (Kanaya et al. J. Geophys. Res.: Atmos. 2007, 112, (D21)), and New York (Ren et al. Atmos. Environ. 2006, 40, 252–263). The active photochemistry facilitates the production of secondary pollutants. It is mainly initiated by the photolysis of nitrous acid and ozonolysis of olefins and maintained by an extremely efficiently radical cycling process driven by nitric oxide. This boosted radical recycling generates fast photochemical ozone production rates that are again comparable to those during summer photochemical smog. The formation of ozone, however, is currently masked by its efficient chemical removal by nitrogen oxides contributing to the high level of wintertime particles. The future emission regulations, such as the reduction of nitrogen oxide emissions, therefore are facing the challenge of reducing haze and avoiding an increase in ozone pollution at the same time. Efficient control strategies to mitigate winter haze in Beijing may require measures similar as implemented to avoid photochemical smog in summer.
LB  - PUB:(DE-HGF)16
C6  - pmid:31418557
UR  - <Go to ISI:>//WOS:000487163000017
DO  - DOI:10.1021/acs.est.9b02422
UR  - https://juser.fz-juelich.de/record/866667
ER  -