Meng Zhaowei, Lei Peiyu, Zhang Tongjun, Chang Feng
Institute for Environmental Health Research and Evaluation, Shaanxi Provincial Centre for Disease Control and Prevention, Xi'an 710054, China.
Wei Sheng Yan Jiu. 2020 Jan;49(1):75-85. doi: 10.19813/j.cnki.weishengyanjiu.2020.01.013.
To master the variation characteristics of PM_(2. 5) mass concentration in Lianhu district and Yanta district of Xi'an City and its relationship with meteorological conditions.
From 2015 to 2018, according to the environmental monitoring data of six main urban areas in Xi'an City in 2012, including NO_2, SO_2, PM_(10), PM_(2. 5), CO and O_3, air samples were collected in the relatively heavy polluted Lianhu district and the relatively light Yanta district of Xi'an City. The mass concentration test of PM_(2. 5) was carried out in accordance with the Ministry of Environmental Protection's "Determination of atmospheric articles PM_(10) and PM_(2. 5) in ambient air by gravimetric method "(HJ 618-2011). According to the Ambient air quality standards(GB 3095-2012), the average daily secondary concentration limit(75 μg/m~3) was used for statistical analysis and evaluation according to different annual, regional and seasonal test result. Meteorological data of Xi'an City were collected, including daily average temperature, daily average pressure, daily average relative humidity, daily average wind speed, daily precipitation, maximum temperature and minimum temperature, and the relationship between PM_(2. 5)concentration and meteorological factors was analyzed.
A total of 660 air samples were collected and qualified, the median concentration of PM_(2. 5) was 71 μg/m~3. 356 air samples were qualified, and the pass rate was 53. 94%. The sample pass rate for each year from high to low was 2017>2018>2016>2015(P<0. 001), The average level of PM_(2. 5) mass concentration from high to low was 2015>2016>2017>2018(P<0. 001). There was no significant difference in the sample pass rate and PM_(2. 5)mass concentration between Lianhu district and Yanta district(P>0. 05). The qualified rate of samples from high to low in different seasons was summer>spring> autumn>winter(P<0. 05). The average concentration of PM_(2. 5) in different seasons from high to low was winter>autumn>spring>summer(P<0. 001). Mean temperature, mean air pressure, average wind speed, average relative humidity, precipitation and lowest temperature were significantly correlated with PM_(2. 5) mass concentration(P<0. 001). The determination coefficients of multiple regression analysis of meteorological factors in Lianhu and Yanta regions were 0. 390 and 0. 373, respectively.
The air quality in Lianhu district and Yanta district of Xi'an City had improved year by year, and the pollution of PM_(2. 5) in autumn and winter was more serious. Meteorological conditions affected the concentration level of PM_(2. 5) in the atmosphere.
掌握西安市莲湖区和雁塔区PM₂.₅质量浓度变化特征及其与气象条件的关系。
2015年至2018年，依据2012年西安市六个主城区的环境监测数据，包括NO₂、SO₂、PM₁₀、PM₂.₅、CO和O₃，在西安市污染相对较重的莲湖区和污染相对较轻的雁塔区采集空气样本。PM₂.₅质量浓度测试按照环境保护部《环境空气PM₁₀和PM₂.₅的测定重量法》（HJ 618 - 2011）进行。根据《环境空气质量标准》（GB 3095 - 2012），采用日均二级浓度限值（75μg/m³），依据不同年份、区域和季节的测试结果进行统计分析和评价。收集西安市气象数据，包括日平均气温、日平均气压、日平均相对湿度、日平均风速、日降水量、最高气温和最低气温，并分析PM₂.₅浓度与气象因素的关系。
共采集并合格660份空气样本，PM₂.₅中位数浓度为71μg/m³。合格样本356份，合格率为53.94%。各年份样本合格率从高到低依次为2017＞2018＞2016＞2015（P＜0.001），PM₂.₅质量浓度平均水平从高到低依次为2015＞2016＞2017＞2018（P＜0.001）。莲湖区和雁塔区样本合格率及PM₂.₅质量浓度无显著差异（P＞0.05）。不同季节样本合格率从高到低依次为夏季＞春季＞秋季＞冬季（P＜0.05）。不同季节PM₂.₅平均浓度从高到低依次为冬季＞秋季＞春季＞夏季（P＜0.001）。平均气温、平均气压、平均风速、平均相对湿度、降水量和最低气温与PM₂.₅质量浓度显著相关（P＜0.001）。莲湖区和雁塔区气象因素多元回归分析的决定系数分别为0.390和0.373。
西安市莲湖区和雁塔区空气质量逐年改善，秋冬季节PM₂.₅污染更为严重。气象条件影响大气中PM₂.₅的浓度水平。
