Observed Chemical Characteristics of Long-Range Transported Particles at a Marine Background Site in Korea

Abstract

Deokjeok Island is located off the west coast of the Korean Peninsula and is a suitable place to monitor the long-range transport of air pollutants from the Asian continent. In addition to pollutants, Asian dust particles are also transported to the island during long-range transport events. Episodic transport of dust and secondary particles was observed during intensive measurements in the spring (March 31-April 11) and fall (October 13-26) of 2009. In this study, the chemical characteristics of long-range-transported particles were investigated based on highly time-resolved ionic measurements with a particle-into-liquid system coupled with an online ion chromatograph (PILS-IC) that simultaneously measures concentrations of cations (Li+, Na , NH4+, K+, Ca2+, Mg2+) and anions (F-, C1-, NO3-, SO42-). The aerosol optical thickness (AOT) distribution retrieved by the modified Bremen Aerosol Retrieval (M-BAER) algorithm from moderate resolution imaging spectroradiometer (MODIS) satellite data confirmed the presence of a thick aerosol plume coming from the Asian continent towards the Korean peninsula. Seven distinctive events involving the long-range transport (LRT) of aerosols were identified and studied, the chemical components of which were strongly related to sector sources. Enrichment of acidic secondary aerosols on mineral dust particles, and even of sea-salt components, during transport was observed in this study. Backward trajectory, chemical analyses, and satellite aerosol retrievals identified two distinct events: a distinctively high [Ca2++Mg2]/[Na+] ratio (>2.0), which was indicative of a preprocessed mineral dust transport event, and a low [Ca2++Mg2+]/[Na+] ratio (<2.0), which was indicative of severe aging of sea-salt components on the processed dust particles. Particulate C1- was depleted by up to 85% in spring and 50% in the fall. A consistent fraction of carbonate replacement (FCR) averaged 0.53 in spring and 0.55 in the fall. Supporting evidences of C1- enrichment on the marine boundary layer prior to a dust front were also found. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of the Air & Waste Management Association for sector and air mass classifications of clean and LRT cases.

Investigations of Transported and Local Emissions on Particle Compositions in Korea

“…6(a). In this case, the Cl -concentration does not have significant correlation with Na + suggesting that it is not sea salt (Wilson, 1975;Cayetano et al, 2011). Also, if these increases in Cl -had been from biomass burning, the concentration of K + would have to also increase simultaneously (Li et al, 2003); however, this was not observed.…”

“…Many years of high economic growth in major urban centers in Northeast Asia have been achieved by vigorous industrializations resulting in significant emissions of pollutants that can be long-range transported (LRT) over the region (Foell et al, 1995;Keating and Zuber 2007; particles on background air conditions (Yang et al 2004;Kim et al, 2009;Sahu et al, 2009;Batmunkh et al, 2011;Cayetano et al, 2011). Studies in Seoul (Song et al, 2007;Jung et al, 2010;Jeong et al, 2011) at urban monitoring sites downwind of the Asian continent have provided significant understanding regarding local and LRT emissions.…”

Seasonal variation and chemical characterization of PM&lt;sub&gt;2.5&lt;/sub&gt; in northwestern Philippines

“…The enrichment factors of the chemical markers of the identified sources are tabulated in Table 4 )/Na + of 5.7, which is about the value of enrichment factor of a certified reference material of China loess soil (Nishikawa et al, 2000), while that of the industrial emission factor (1.6) corresponds to the enrichment factor of sea salt ageing on the processed dust particles from a marine background site in Korea (Cayetano et al, 2011).…”

“…Rapid industrialization and urban development in the recent decades in Asia, particularly in mainland China, has led to an increase in energy consumption and consequently pollutant emissions. High emissions from the Asian main continent that is transported to other East Asian countries can contribute to elevated concentrations of ambient fine particulate concentration 20 elsewhere (Oh et al, 2015;Gu et al, 2016;Lin et al, 2014;Zhu et al, 2017;Cayetano et al, 2011). Similarly, biomass burning from land clearing in countries like Indonesia and Malaysia has also affected their neighboring countries with reduced visibility and poor air quality (Aouizerats et al, 2015;Forsyth , 2014).…”

A Special Issue of JA&WMA on Papers from the “Leapfrogging Opportunities for Air Quality Improvement Conference”

“…Geng et al 11 characterize single particles and particle size distribution of transported aerosol at Gosan during Asian dust storms. Measurements at Deokjeok Island (off the west coast of the Korean Peninsula) by Cayetano et al 12 ]/Na þ ratio >2) related to dust transport events, whereas Cl À is enriched in on the marine boundary layer prior to the arrival of the dust plume.…”