Aerosol size distributions during haze episodes in winter in Jinan, China--颗粒学报PARTICUOLOGY

Sun, Y., Zhou, X., & Wang, W. (2016). Aerosol size distributions during haze episodes in winter in Jinan, China. Particuology, 28, 77-85. https://doi.org/10.1016/j.partic.2015.12.001

Aerosol size distributions during haze episodes in winter in Jinan, China

Yuwei Sun ^{a b}, Xuehua Zhou ^a *, Wenxing Wang ^a

a Environment Research Institute, Shandong University, Jinan 250100, Shandong, China
b College of Environmental Science and Engineering, Jilin Normal University, Siping 136000, Jilin, China

10.1016/j.partic.2015.12.001

Volume 28, October 2016, Pages 77-85

Received 4 July 2014, Revised 26 November 2015, Accepted 3 December 2015, Available online 7 February 2016, Version of Record 4 August 2016.

E-mail: xuehuazhou@sdu.edu.cn

Highlights

• Particle number concentration and size distribution during haze episodes in winter were analyzed.

• Sharp increases in the 500–600 nm particle concentrations during haze episodes were observed.

• 500–600 nm particles were mainly formed via evaporation of droplets present in cloud and fog.

• New particle formation events were identified and studied on clear and haze days.

Abstract

Number concentrations and distributions of 10–10,000 nm particles in a large city (Jinan) in the North China Plain were measured in winter 2009. The mean number concentrations of nucleation mode (10–20 nm), Aitken mode (20–100 nm), and accumulation mode (100–1000 nm) particles, as well as total particles were 925, 6898, 2476, and 10,299 cm⁻³, respectively. Two severe haze episodes, with elevated concentrations caused by pollutants accumulating, were observed. Accumulation mode particle concentrations were significantly higher during the episodes than on clear days, and nucleation mode particle concentrations were pronouncedly higher on clear days than during the episodes. The peaks of dominant number, surface area, and mass size distributions were around 30–50, 200–300, and 200–400 nm, respectively, both during the haze episodes and on clear days, but elevated mass and surface area concentrations around 500–600 nm were also observed during the haze episodes, suggesting these particles had significant contributions to haze formation. These particles were probably formed through larger droplets in cloud and fog evaporating. Two new particle formation events, probably triggered by strong photochemical processes on clear days and significant traffic emissions during haze episode 2, were found. Significant insights were made into haze formation in a polluted Chinese urban area.

Graphical abstract

Keywords

Aerosol size distributions; Hazy and clear days; Polluted city; China

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