兰州市CO污染分布特征

Distribution characteristics of carbon monoxide pollution in Lanzhou

为探究兰州市CO的分布特征,利用2015~2020年兰州市国控空气质量监测站点的CO等6项空气污染物逐小时质量浓度资料,并结合同期兰州市常规气象观测资料,分析了兰州市CO污染的特征,探讨了CO浓度与其他空气污染物和气象要素的关系。结果表明,2015~2020年间,兰州市区的CO平均浓度逐年下降,而榆中兰大校区却在2017年之后出现了上升趋势;兰州市区和榆中兰大校区的CO浓度呈现出冬季高夏季低的“U字型”月度变化特征,采暖期CO浓度值是非采暖期的2倍左右;兰州市区CO浓度呈现出双峰型日变化,峰值主要出现在09:00和21:00,榆中兰大校区则为单峰型,峰值出现在12:00;CO和NO_(2)具有相似的双峰型日变化特征,两者之间的相关系数为0.718,而CO与SO_(2)、PM_(2.5)和PM_(10)具有相似的“U字型”月度变化特征;气温和风速是影响兰州市CO浓度的主要气象要素。

In order to investigate the distribution characteristics of carbon monoxide(CO) in Lanzhou, the hourly concentration data of six air pollutants including CO obtained from the national air quality monitoring sites in Lanzhou from 2015 to 2020 were used, considering the regular meteorological observation data in the same period, the characteristics of CO pollution in Lanzhou and the relationship between CO concentration and other air pollutants as well as meteorological elements were analyzed.The results showed that the average concentration of CO in Lanzhou city decreased year by year from 2015 to 2020, while Yuzhong county showed an upward trend after 2017. The CO concentration in Lanzhou city and Yuzhong county showed a "U-shaped" monthly change characteristic with a high concentration in winter and a low concentration in summer, and the CO concentration during the heating period was about twice than that of the non-heating period. The CO concentration in Lanzhou city had a bimodal diurnal variation with the peaks appearing mainly at 09:00 and 21:00, while the Yuzhong county had a single peak appearing at12:00. CO and NO_(2) had similar bimodal diurnal variation characteristics with a correlation coefficient of 0.718, while CO and SO_(2),PM_(2.5), PM_(10) had similar "U-shaped" monthly variation characteristics. Air temperature and wind speed were the main meteorological elements which affected the CO concentration in Lanzhou.