Water-Soluble Ionic Characteristics of Aerosols in the Marine Boundary Layer over the Yellow Sea during the KORUS-AQ Campaign

Joo Wan Cha,Sang-Boom Ryoo,Hee-Jung Ko,Beomchel Shin,Yun Kyu Lim

doi:10.1007/s13143-019-00151-8

Joo Wan Cha, Sang-Boom Ryoo + Show 3 more

Open Access

https://doi.org/10.1007/s13143-019-00151-8

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Abstract

Major compositions of water-soluble ionic species in particulate matter less than 10 and 2.5 μm in diameter (PM10 and PM2.5, respectively) over the Yellow Sea were collected during the Korea–United States Air Quality (KORUS-AQ) campaign in 2016 onboard the research vessel Gisang 1. The secondary ionic species (NH4+, nss-SO42−, and NO3−) in PM10 and PM2.5 accounted for 84% and 89% of the total analyzed species. NH4+ was strongly correlated with non-sea salt (nss) SO42− (nss-SO42−) in PM10 and PM2.5; NO3− was closely correlated with Na+, Mg2+, and nss-Ca2+ in PM10 and NH4+ in PM2.5. High mass concentrations of methane sulfonic acid (MSA, CH3SO3−), the main source of natural sulfates over the Yellow Sea, were observed. The concentrations of MSA were found to show an increasing trend over the Yellow Sea in recent years. Biogenic sulfur contributions to the total nss-SO42− (MSA/nss-SO42− ratio) over the Yellow Sea ranged from 1.4% to 9.2% in PM10 and from 0.68% to 9.5% in PM2.5 during the cruise. Thus, biogenic nss-SO42− must be included, especially in the spring and early summer seasons, when biological activities are elevated in Northeast Asia. We classified the high aerosol mass concentration cases such as Asian dust and haze cases. In Asian dust cases, the ratio of NO3− to nss-SO42− in the aerosols showed that mobile (stationary) sources mainly affected PM10 (PM2.5). The major chemical species for Asian dust cases over the Yellow sea were CaCO3, Ca(NO3)2, Mg(NO3)2, Na(NO3)2, and sea salt. In haze cases over the Yellow sea, the contributions from stationary sources are high and the major species were (NH4)2SO4 and NH4NO3 in PM10 and PM2.5, respectively.

Highlights

Recent economic development in Northeast Asia, especially in China, has resulted in frequent occurrences of high aerosol mass concentration events in the region (Ding and Liu 2014; Wang and Chen 2016)
89% of the total analyzed species in PM10 and PM2.5, respectively. This implies that the aerosols collected over the Yellow Sea during the campaign were strongly affected by the anthropogenic emissions over land
Most of the nss-SO42− over the Yellow Sea in May 2016 came from the Shandong Peninsula and Northeast China

Summary

Introduction

Recent economic development in Northeast Asia, especially in China, has resulted in frequent occurrences of high aerosol mass concentration events in the region (Ding and Liu 2014; Wang and Chen 2016). The recent increase in anthropogenic emissions can alter aerosol compositions and their characteristics over the Yellow Sea. The Korea-United States Air Quality (KORUS-AQ) campaign was an international, multi-organization mission to observe air quality across the Korean peninsula and surrounding waters. KORUS-AQ was conducted by the National Aeronautics and Space Administration (NASA) and their international partners from April to June 2016. National Institute of Meteorological Science (NIMS) of the Korea Meteorological Administration (KMA) measured atmospheric aerosols over the Yellow Sea, which was affected by aerosols originating in various regions of China and Korea during the campaign periods. KORUS-AQ integrated observations from ships, aircrafts, ground sites, and satellites, in conjunction with air quality models, to understand the factors governing air quality across urban, rural, and coastal interfaces in Northeast Asian (https://espo.nasa.gov/home/korus-aq)

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