Variations in <i>N</i><sub>cn</sub> and <i>N</i><sub>ccn</sub> over marginal seas in China related to marine traffic emissions, new particle formation and aerosol aging

Abstract

Abstract. In this study, a cruise campaign was conducted over marginal seas in China to measure the concentrations of condensation nuclei (Ncn), cloud condensation nuclei (Nccn) and other pollutants from day of year (DOY) 110 to DOY 135 of 2018. The ship self-emission signals were exhaustively excluded, and the mean values of Nccn during the cruise campaign were found to slightly increase from 3.2±1.1×103 cm−3 (mean ± standard deviation) at supersaturation (SS) of 0.2 % to 3.9±1.4×103 cm−3 at SS of 1.0 %, and the mean value for Ncn was 8.1±4.4×103 cm−3. Data analysis showed that marine traffic emissions apparently largely contributed to the increase in Ncn in the daytime, especially in the marine atmospheres over heavily traveled sea zones; however, the fresh sources made no clear contribution to the increase in Nccn. This finding was supported by the quantitative relations between Ncn and Nccn at SS = 0.2 %–1.0 % against the mixing ratios of SO2 in the ship self-emission plumes – i.e., a 1 ppb increase in SO2 corresponded to a 1.4×104 cm−3 increase in Ncn but only a 30–170 cm−3 increase in Nccn, possibly because of abundant organics in the aerosols. Smooth growth can be observed in the marine-traffic-derived particles, reflecting aerosol aging. The estimated hygroscopicity parameter (κ) values were generally as high as 0.46–0.55 under the dominant onshore winds, suggesting that inorganic ammonium aerosols likely acted as the major contributor to Nccn largely through aerosol aging processes of decomposing organics. Moreover, the influences of the new transported particles from the continent on the Ncn and Nccn in the marine atmosphere were investigated.

Measurement report: New particle formation characteristics at an urban and a mountain station in northern China

“…The total number concentration from 4 to 3000 nm, measured by a condensation particle counter (CPC; TSI Model 3775), was used to calibrate the particle number size distributions from the FMPS according to the method suggested by Zimmerman et al (2015). More details about the instrument are found in previous studies Gao et al, 2020). The particle number size distribution measured by the FMPS correlated well with the SMPS during the comparison in laboratory after being calibrated (Lee et al, 2013).…”

Characterizing the hygroscopicty of growing particles in the Canadian Arctic summer

“…This method has been previously used in studies where it is not possible to size select the particles before they are counted by the CCNC (e.g. Collins et al, 2013;Gao et al, 2020).…”

Tropospheric aerosol hygroscopicity in China

“…Measurements of size-resolved CCN activities have been discussed in a number of previous studies (Lance et al, 2006;Frank et al, 2007;Petters et al, 2007;Rose et al, 2008;Good et al, 2010;Moore et al, 2010;Rose et al, 2010;Bougiatioti et al, 2011). In many studies, an aerosol flow sampled from the ambient air, after being dried to < 20 % RH, is passed through an aerosol neutralizer and then a DMA to produce quasi-monodisperse aerosols.…”

“…Wang et al, 2018a), Qingdao (K. , Shanghai (Leng et al, 2013(Leng et al, , 2014, Guangzhou (Duan et al, 2017(Duan et al, , 2018, and Mt. Huang (Fang et al, 2016), as well as over marginal seas in China (Zhu et al, 2019;Gao et al, 2020) and the northwestern Pacific (J. Zhu et al, 2019).…”