生态环境学报2017，Vol.26Issue(6)：1001-1008,8.DOI:10.16258/j.cnki.1674-5906.2017.06.013
合肥市能见度与相对湿度、PM2.5质量浓度的定量关系
Quantified Relationships among the Visibility, Relative Humidity and PM2.5 Mass Concentration in Hefei City
摘要
Abstract
To understand the impacting factors of the visibility in Hefei, and provide scientific basis for the urban atmospheric visibility improvement, the hourly meteorological and environmental observations from January 2013 to December 2015 in Hefei city were used to investigate the relationships among atmospheric visibility, relative humidity (RH), and PM2.5 mass concentration. The statistical relationships between RH and PM2.5 were set up for different atmospheric visibility grades. It was found that atmospheric visibility in Hefei was jointly controlled by both RH and PM2.5. Under low RHconditions (RH<60%), the decrease in visibility was mainly ascribed to the increase of the PM2.5 mass concentration. High RH and PM2.5 mass concentration can significantly reduce the atmospheric visibility. Under high RH conditions (RH≥60%), due to the hygroscopic growth of the fine particulate can efficiently enhance light absorption and scattering, the visibility decreases more obvious in slight pollution. On average, the visibility was reduced by 0.172 km with 1% increment of RH when RH≥60%. When RH≥90%, the average visibilities were mostly less than 5 km. The best fitting relationship between the PM2.5 mass concentration and the visibility was a power function, and the effects of PM2.5on visibility were strongly significant when the RH is less than 60% but larger than or equal 40%. The PM2.5 mass concentration threshold that influences the atmospheric visibility decreases with increasing RH.Particularly, decreases in the PM2.5 mass concentration can lead to rapid increase in visibility when the PM2.5 mass concentration was less than 46μg·m-3. As the RH increases, or PM2.5 mass concentration increases, the frequency of low visibility rises. High RH and large PM2.5 mass concentration can significantly induce the occurring of lower atmospheric visibility. The factor of probability that visibility <5 km in a day was greater than 75%, when the visibility was below 7 km in its previous day and RH>75% with PM2.5>65μg·m-3 in the day. When the PM2.5 mass concentration reaches the moderately polluted level or above in its previous day, its visibility increases with RH decrease during this day, especially, the factor of probability that visibility <5 km in this day can reach 70% if RH reaches 80%.关键词
能见度/相对湿度/PM2.5质量浓度/定量关系/合肥Key words
Visibility/Relative humidity/PM2.5 mass concentration/Quantified relationship/Hefei分类
资源环境引用本文复制引用
张浩,石春娥,吴必文,杨元建..合肥市能见度与相对湿度、PM2.5质量浓度的定量关系[J].生态环境学报,2017,26(6):1001-1008,8.基金项目
安徽省省级环境保护科研项目(2015-002) （2015-002）
中国气象局气候变化专项(CCSF201726) （CCSF201726）
