Industrialization and urbanization have resulted in increasing concentrations of air pollutants, posing harm to humans and the environment, and increasing social and economic costs. Changes in the air pollutant concentration are highly influenced by meteorological fields. The meteorological conditions of the Korean Peninsula are influenced by the distinctive seasonal monsoon, the Western North Pacific Subtropical High (WNPSH), the El Nino-Southern Oscillation (ENSO), and other atmospheric variabilities. The present study describes the influence of meteorological variability on air pollutants in the atmosphere of the Korean Peninsula. This study explores three subjects: the relationship between the atmospheric field and seasonal surface ozone (O3), the influence of WNPSH on surface O3 during summer, and the relationship between ENSO and the variability in surface particulate matter concentration.
Tropospheric (surface) O3, which plays an important role in climate variation and air quality, has increased dramatically in East Asia due to the rapid economic growth. In Korea, the relationship between meteorological conditions and surface O3 varies seasonally. For better understanding of this process, this study performed offline simulations using a climate-chemistry model. The model suitably represents the observed annual cycle of surface O3 over East Asia, including the spring/autumn peaks and summer troughs. Increases in O3 are associated primarily with the westerly wind anomaly during spring, and with surface warming during the autumn and summer. Moreover, a decrease in O3 during the summer likely results from the transportation of O3-depleted air masses by anomalous southeasterly winds. Reduced cloud cover increases O3 levels significantly during all seasons except winter. The relationship between ENSO and O3 concentrations in Korea is also examined. Spring O3 levels tends to be elevated following mature-phase El Nino winters, whereas elevated levels during summer and autumn follows La Nina winters.
WNPSH is a crucial circulation system affecting the East Asian summer monsoon region, including the Korean Peninsula, but its linkage to surface O3 had not previously been identified. This study aimed to identify the relationship between WNPSH and O3 levels across the Korean Peninsula. For this purpose, a linear regression analysis was performed to assess WNPSH-related variations in observed O3 concentrations at 151 air quality monitoring sites during 2001 to 2015. The results showed that enhanced WNPSH contributes to the observed increase in O3 levels during summer (June to August), with the opposite trend observes during weakened WNPSH years. We found that anomalous precipitation due to altered circulation patterns is the main contributor to changes in O3 level. This implies that summer O3 in Korea is highly sensitive to interannual atmospheric variability.
Particles less than 10 μm in diameter (PM10) over the Korean Peninsula, were analyzed from 2001 to 2015 to examine the influence of ENSO on subseasonal PM10 variability. The PM10 data were obtained from 151 air quality monitoring stations provided by the Korea Environment Corporation. Lead?lag correlation analysis, which was performed to investigate the connection between the November to February (NDJF) NINO3 index and seasonal mean PM10 data, does not show any statistically significant correlations. However, using five-pentad moving-averaged PM10 data, statistically significant correlations between the NDJF NINO3 index and PM10 variability are found in four subseasonal periods, with alternating positive and negative correlations. In the periods during which PM10 levels on the Korean Peninsula are positively (negatively) correlated with the ENSO index, the positive PM10 anomalies are associated with El Nino (La Nina) years, which implies that high-PM10 events could be modulated by the ENSO phase. In addition, this ENSO-related PM10 variation is negatively correlated with ENSO-related precipitation in the Korean Peninsula, indicating that more or less wet deposition leads to either lower or higher PM10 levels, respectively. Therefore, we conclude that the ENSO-induced precipitation anomalies over the Korean Peninsula are mainly responsible for ENSO-related PM10 variations.
This study confirmed that intra-seasonal or seasonal meteorological variations influence surface O3 and particulate matter distribution in the Korean Peninsula. This study also suggests that meteorological fields must be explicitly considered for research on air pollutants. The results of this study will improve our understanding of the relationship between air pollutants and meteorological fields.