关键词: 大气污染物, 街道峡谷, 移动观测, 时空分布, Pearson相关性分析, 沈阳市

Abstract: To explore the variation of air pollutant concentration and the influence of meteorological factors on air pollutant concentration in urban street canyon, we used portable air pollution monitoring equipment to detect five kinds of air pollutants (CO, SO₂, PM₁, PM_2.5, and PM₁₀) in the Qingnian Street of Shenyang during the peak and off peak periods under clean weather and polluted weather. Pearson correlation analysis was used to assess the influence of meteorological factors on the mass concentrations of five air pollutants. The results showed that the distribution of air quality index (AQI) in the Qingnian Street had significant spatial and temporal variations over short-term. The spatial distribution of AQI showed a pattern of “high in the north and low in the south” under clean weather, and a pattern of “high in the south and low in the north” under polluted weather, with high pollutant concentration at road intersections. Temporally, the concentrations of the five pollutants were higher under polluted weather than that under clean weather. They were the highest in peak commuting time and the lowest in off peak commuting time. The concentrations of air pollutants were significantly positively correlated with air temperature and relative humidity, and negatively correlated with air pressure in clean weather. In polluted weather, air temperature was negatively correlated with PM₁; relative humidity was negatively correlated with SO₂ and CO concentrations, positively correlated with PM_2.5 and PM₁₀ concentrations; and pressure was negatively correlated with CO, SO₂, PM₁ and PM_2.5 concentrations. This study provided a reference for future studies on air pollution control and regional air pollutant transport in street canyons.

Key words: air pollutant, urban street canyon, mobile monitoring, spatial and temporal distribution, Pearson correlation analysis, Shenyang.