银川大气污染物浓度变化特征及其与气象条件的关系

利用2013年银川地区6个监测点污染物质量浓度和同期气象要素数据，对区域内污染物浓度变化特征及其与气象条件的关系进行分析。结果表明：银川市区PM10年均值超标0.7倍，PM_2.5年均值超标0.4倍，SO₂和NO₂也有一定程度超标，CO和O₃未超标|1、2、11月和12月为SO₂、NO₂、PM₁₀、PM_2.5、CO质量浓度较高月，O₃浓度最高月为5月，次高月为10月|9:00-12:00和21:00-00:00是SO₂、NO₂、PM₁₀、PM_2.5和CO质量浓度较高的两个时段，O₃浓度一般于15:00达到最大；6类污染物普遍表现出季节性的准7 d周期和全年性的准30 d周期|空气质量状况良的频率是56 %，轻度污染26 %，优仅为12%；首要污染物以PM₁₀、PM_2.5和SO₂为主|风速与SO₂、NO₂和CO具有良好的负相关关系，与O₃则呈显著正相关关系，风速对PM₁₀和PM_2.5影响较复杂，当风速小于某一值时，有利于PM₁₀和PM_2.5扩散，当风速达到一定程度后，又会导致PM₁₀和PM_2.5浓度的增加|降水对污染物有较好的冲刷作用，且对SO₂的清除作用最明显，对O₃的清洁作用最弱。

Characteristics of concentration of air pollutant and its relationship with meteorological conditions in Yinchuan

Using the air pollutants’ concentration data at 6 monitoring points of Yinchuan and the corresponding meteorological data in 2013, characteristics of the air pollutants’ concentrations and its relationship with the meteorological conditions were analyzed. The results show that annual average PM₁₀ and PM_2.5 concentration are 0.7 times and 0.4 times greater than the standard value. Annual mean SO₂ and NO₂ concentrations both exceed in a certain degree, while CO and O₃ do not exceed the standard values. Concentrations of SO₂, NO₂, PM₁₀, PM_2.5 and CO are high in January, February, November and December, while that of O₃ is high in May and October. There are two high peaks a day for SO₂, NO₂, PM₁₀, PM_2.5 and CO concentrations in one day, i.e. from 09:00 to 12:00 and from 21:00 to 00:00. However, the maximum O3 concentration generally occurs at 15:00. All pollutants concentrations generally show a seasonal quasi 7-day cycle and a yearly quasi 30-day cycle. Frequency of air quality with good grade accounts for 56 %, while those with light pollution and excellent air quality are 26 % and 12 % respectively. The primary pollutants are PM₁₀, PM_2.5 and SO₂. Wind speed has a significant negative correlation with SO₂, NO₂ and CO concentrations, while it has a significant positive correlation with O3 concentration. Effect of wind speed on PM₁₀ and PM_2.5 concentrations is complex. When wind speed is less than a certain value, it is beneficial to PM₁₀ and PM_2.5 diffusion. On the other hand, when wind speed reaches a certain level, it can lead to increase concentrations of PM₁₀ and PM_2.5. Precipitation has good cleanup effect for pollutants, especially for SO₂, while it had a weak effect on O₃.