Spatiotemporal Relations between PM10 Concentrations and Relative Humidity in South Korea

Time-series analyses of nationwide PM10 concentrations and relative humidity showed that they had strong seasonality and were correlated with each other in South Korea. A significant negative correlation was found between them in most locations, but their relationship was not significant at a few coastal locations.
Weekly and daily analyses indicated that their cross-correlation was peaked when PM10 concentrations were 1-week lagged behind relative humidity on average. Therefore, it is likely that PM10 levels at a given time had been influenced by the moisture conditions of the previous week. Long-term(2007~2016) trend of PM10 concentrations were extracted by removing seasonal effects within the original time-series using a deseasonalization model, and it was fitted into a linear regression line for prediction of PM10 concentrations. The prediction errors of the deseasonalization model were measured as the root-mean-square error (RMSE), and they were significantly correlated with seasonal relative humidity variance except summer. Geographically, prediction accuracy of PM10 concentrations was higher in locations, where the overall PM10 levels were lower and the decreasing trends of PM10 concentrations were higher during the study period.