Nocturnal aerosol particle formation in the North China Plain

Abstract

New particle formation is one of the major sources of atmospheric aerosol particles. Beside daytime nucleation, nocturnal new particle formation was also found in different regions around the world. Compared with daytime nucleation events, the understanding of nocturnal ones is still sparse. The variety of aerosol particle physico-chemical properties, including particle number size distribution, volatility and hygroscopicity were measured in the North China Plain during July–August 2013. During the observation period, rapid increase in ultrafine particle number concentration was attributed to new particle formation. The nocturnal new particle formation rate was 45 cm^–3s^–1, which is 1.25 times higher than an observed daytime value. Condensation sink was found to be 0.055 s^–1