Guan Qingyu, Cai Ao, Wang Feifei, Yang Liqin, Xu Chuanqi, Liu Zeyu
Key Laboratory of Western China's Environmental Systems (Ministry of Education), Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
Key Laboratory of Western China's Environmental Systems (Ministry of Education), Gansu Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China; Gansu Building Research Institute, Lanzhou, 730000, China.
Environ Pollut. 2017 Nov;230:189-198. doi: 10.1016/j.envpol.2017.06.045. Epub 2017 Jun 23.
To investigate the spatial and temporal behaviors of particulate matter in Lanzhou, Jinchang and Jiayuguan during 2014, the hourly concentrations of PM2.5 and PM10 were collected from the Ministry of Environmental Protection (MEP) in this study. The analysis indicated that the mean annual PM10 (PM2.5) concentrations during 2014 were 115 ± 52 μg/m (57 ± 28 μg/m), 104 ± 75 μg/m (38 ± 22 μg/m) and 114 ± 72 μg/m (32 ± 17 μg/m) in Lanzhou, Jinchang and Jiayuguan, respectively, all of which exceeded the Chinese national ambient air quality II standards for PM. Higher values for both PM fractions were generally observed in spring and winter, and lower concentrations were found in summer and autumn. Besides, the trend of seasonal variation of particulate matter (PM) in each city monitoring site is consistent with the average of the corresponding cities. Anthropogenic activities along with the boundary layer height and wind scale contributed to diurnal variations in PM that varied bimodally (Lanzhou and Jinchang) or unimodally (Jiayuguan). With the arrival of dust events, the PM10 concentrations changed dramatically, and the PM10 concentrations during dust storm events were, respectively, 19, 43 and 17 times higher than the levels before dust events in Lanzhou, Jinchang and Jiayuguan. The ratios (PM2.5/PM10) were lowest, while the correlations were highest, indicating that dust events contributed more coarse than fine particles, and the sources of PM are similar during dust storms. The relationships between local meteorological parameters and PM concentrations suggest a clear association between the highest PM concentrations, with T ≤ 7 °C, and strong winds (3-4 scale). However, the effect of relative humidity is complicated, with more PM10 and PM2.5 exceedances being registered with a relative humidity of less than 40% and 40-60% in Lanzhou, while higher exceedances in Jinchang appeared at a relative humidity of 80-100%.
为研究2014年兰州、金昌和嘉峪关颗粒物的时空行为，本研究从环境保护部（MEP）收集了PM2.5和PM10的小时浓度数据。分析表明，2014年兰州、金昌和嘉峪关的年平均PM10（PM2.5）浓度分别为115±52μg/m³（57±28μg/m³）、104±75μg/m³（38±22μg/m³）和114±72μg/m³（32±17μg/m³），均超过了中国国家环境空气质量PM二级标准。两个颗粒物组分的较高值通常出现在春季和冬季，较低浓度出现在夏季和秋季。此外，各城市监测点颗粒物（PM）的季节变化趋势与相应城市的平均值一致。人为活动以及边界层高度和风级导致了PM的日变化呈双峰模式（兰州和金昌）或单峰模式（嘉峪关）。随着沙尘事件的到来，PM10浓度发生显著变化，兰州、金昌和嘉峪关沙尘风暴事件期间的PM10浓度分别比沙尘事件前的水平高出19倍、43倍和17倍。（PM2.5/PM10）比值最低，而相关性最高，表明沙尘事件贡献的粗颗粒比细颗粒更多，且沙尘风暴期间PM的来源相似。当地气象参数与PM浓度之间的关系表明，最高PM浓度与T≤7°C以及强风（3 - 4级）之间存在明显关联。然而，相对湿度的影响较为复杂，兰州相对湿度低于40%和40 - 60%时，PM10和PM2.5超标情况更多，而金昌相对湿度在80 - 100%时超标情况更高。
