The Impact of Meteorological Factors on PM2.5 Variations in Hong Kong

This paper aims to explore the impact of meteorological factors on PM2.5 concentrations in Hong Kong. The PM2.5 and meteorology data including temperature, pressure, rainfall, relative humidity (RH), wind speed and wind direction from January to December of 2013 were collected. The correlation analysis between PM2.5 and meteorological factors were conducted for each month and season. The meteorology data were classified into several intervals and the mean PM2.5 concentrations for each interval were calculated to see the tendency. According to the correlation analysis results, the PM2.5 concentrations have a positive relationship with pressure with correlation coefficients 0.507 while have negative relationships with temperature, RH, rainfall, wind speed with correlation coefficients -0.512, -0.237, -0.524, -0.284, respectively. In addition, the wind direction influence PM2.5 concentrations through affecting the spreading direction of PM2.5. The north wind in winter increased the PM2.5 in Hong Kong while the south wind in summer decrease the PM2.5. Therefore, the meteorological factors affect the aggregation, diffusion, spread of PM2.5. They have a leading impact on PM2.5 concentrations when the domestic emission stays stable.