광주광역시의 대기오염물질과 기상요소간의 상관관계 분석

Abstract

Chemicals and dust particles generated by human activities not only increase their concentrations in the atmosphere but also further deteriorate the level of air pollution by engendering changes in the physical or chemical characteristics of such particulates. For example, sulfur oxides and nitrogen oxides emitted during the combustion of fossil fuels are converted into sulfates and nitrates, respectively, due to chemical reactions which alter the chemical structures and sizes of the particulates, resulting in a significant impact on the air quality. Since the 1970s, Korea has undergone rapid industrialization under the nationwide economy-first policy which accelerated population growth in urban areas. The sharp population growth has drastically exacerbated many of the country’s environmental problems including air, water and soil pollutions with serious consequences. Air pollution is largely affected by, among others, topographical and meteorological characteristics as well as physical and chemical reactions. Even if all other emission conditions remain constant, the level of air pollution can vary to a great extent according to numerous meteorological factors such as wind direction and speed, atmospheric stability, temperature and humidity. Therefore, it is necessary to reduce emission sources aggravating air pollution and analyze the correlation between air pollutants and meteorological factors in order to lessen the effects of air pollution. Against this backdrop, this study seeks to provide baseline data for a comprehensive, scientific analysis including air pollution and weather forecasts by exploring the correlation between air pollutants and meteorological factors in Gwang-ju Metropolitan City. The meteorological data used in this study is based on the daily averages of hourly data (i.e. temperature, relative humidity, precipitation, wind direction and speed) collected by the AWS (Automatic Weather System) of the Gwang-ju Meteorological Administration, for five years from 2010 to 2014, which conducts weather observations around the clock, whereas the air pollution data is based on the daily averages of the hourly levels of sulfur dioxide (SO2), nitrogen dioxide (NO2), CH4 (methane) and O3 (ozone) recorded by the air pollution monitoring network of the Ministry of Environment during the same timeframe. In Gwang-ju, there are a total of seven monitoring stations dedicated to measuring the levels of pollutants in the atmosphere in Seoseok-dong in Dong-gu, Nongseong-dong in Seo-gu, Juwol-dong in Nam-gu, Geonguk-dong in Buk-gu, Duam-dong, Oseon-dong and Songjeong 1-dong in Gwangsan-gu. For the purpose of this study, however, only the data collected from the monitoring station in Nongseong-dong, Seo-gu is utilized as the station is in the closest proximity to the Gwang-ju Meteorological Administration. In this study, the Pearson correlation coefficient is applied to examine the correlation between air pollutants and meteorological factors with the SPSS statistics and data analysis program. To carry out an effective analysis, the precipitation data of -999 from the meteorological records and the air pollutant data since December 18, 2014 are considered as missing values in the study since no pollution data was available due to the relocation of the monitoring station in Nongseong-dong, Seo-gu. The results of the correlation analysis are as follows: Sulfur dioxide (SO2) is negatively correlated to temperature (-.428, p<0.01), precipitation (-.255, p<0.01), wind speed (-.220, p<0.01) and relative humidity (-.270, p<0.01). Nitrogen dioxide (NO2) is also negatively correlated to temperature (-.501, p<0.01), precipitation (-.178, p<0.01), wind speed (-.519, p<0.01) and relative humidity (-.206, p<0.01). On the other hand, ozone (O3) is positively correlated to temperature (.056, p<0.05) and negatively correlated to relative humidity (-.062, p<0.05), whereas carbon monoxide (CO) is negatively correlated to temperature (-.265, p<0.01), wind speed (-.405, p<0.01) and relative humidity (-.074, p<0.01). Furthermore, particulate matter (PM) is negatively correlated to temperature (-.098, p<0.01), precipitation (-.212, p<0.01), wind speed (-.200, p<0.01) and relative humidity (-.280, p<0.01). In the correlation analysis between air pollutants and meteorological factors between 2010 and 2014, most of the pollutants excluding ozone demonstrated a positive correlation to the weather elements. However, the study confirmed such correlations are relatively weak since the majority of the absolute values of the correlation coefficients are less than 0.4. The correlations are even weaker for ozone of which absolute values are below 0.2. Although the correlation analysis can serve as an effective tool to determine the relationship between the two variables, it is not sophisticated enough to conclude on the causal relationship based on such correlation. In fact, air pollutants and meteorological factors are intricate elements that may have various complicated impacts on each other in many different ways. As such, a more in-depth study is needed to investigate the causative relationship between the two elements in order to fully utilize those data for air pollution and weather forecasts.