@article {27055,
	title = {More Significant Impacts From New Particle Formation on Haze Formation During COVID-19 Lockdown},
	journal = {Geophysical Research LettersGeophysical Research LettersGeophysical Research Letters},
	volume = {48},
	number = {8},
	year = {2021},
	note = {Export Date: 7 June 2021},
	type = {Article},
	abstract = {During the COVID-19 lockdown in 2020, large-scale industrial and transportation emissions were reduced, but high PM2.5 concentration still occurred. This study investigated the variation of particle number size distribution during the lockdown, and analyzed the characteristics of new particle formation (NPF) events and its potential impact on haze formation. Through measurement conducted in urban Beijing during the first 3 months of 2020, and comparison with year-over-year data, the decrease of primary Aitken-mode particles was observed. However, frequencies, formation rates and growth rates of NPF events remained stable between 2020 and 2019 in the same period. As a result, \&amp;gt;25~nm particles produced by NPF events, would play a more important role in serving as the haze formation {\textquotedblleft}seeds{\textquotedblright} compared to those produced by primary emissions. This finding emphasizes the significance on the understanding of NPF mechanisms when making pollution mitigation policy in the future. {\textcopyright} 2021. The Authors.},
	keywords = {Beijing [China], concentration (composition), COVID-19, Earth sciences, Emission control, formation rates, Geophysics, haze, haze formation, industrial emission, Industrial emissions, nanoparticle, new particle formation, Particle number size distribution, particulate matter, PM2.5 concentration, Pollution mitigation, Potential impacts, Primary emissions, size distribution, urban area},
	author = {Tang, L. and Shang, D. and Fang, X. and Wu, Z. and Y. Qiu and S. Chen and X. Li and Zeng, L. and Guo, S. and Hu, M.}
}
