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研究报告

Hygroscopic growth properties of particles in Chengdu and its correction methodology

基金项目：四川省教育厅重点项目（No.15ZA091）；四川省教育厅局校合作项目（No.2014Z155）；成都信息工程大学科研基金（No.CRF201606，KYTZ201324）

摘要：利用2013年6月-2014年5月成都市人民南路四段逐时PM_2.5质量浓度、大气能见度监测资料及同期温江站相对湿度观测数据，分析了该区域相对湿度对大气消光系数的影响，探讨了消光系数湿度订正方法的原理和技术流程.结果表明：针对细颗粒物而言，平均单位质量“湿”消光系数在相对湿度为40%时存在突变（通过了α=0.05的信度检验），当相对湿度小于40%时，平均单位质量“湿”消光系数呈现平稳波动的特征；而当相对湿度介于40%~90%时，平均单位质量“湿”消光系数增长趋势明显；现有的湿度订正方法未能在成都地区起到相应的订正效果；单位质量“湿”消光系数直观上表现为非平稳随机序列，基于单位质量“湿”消光系数和单位质量“干”消光系数在统计意义下应具有一致性的原则，从不确定性分析的角度提出了消光系数湿度订正的新方法，取得了令人满意的结果.

Abstract：By using PM_2.5 mass concentration and atmospheric visibility data at the Renmin Road (S) station and meteorological data at Wenjiang station from June 2013 to May 2014, we analyzed the impact of relative humidity on the atmospheric extinction coefficient. The theory and technical process of the extinction coefficient correction method was also discussed. It is found that the average unit mass "wet" extinction coefficient of fine particles has a turning point at the relative humidity of 40% (passing the Mann-Kendall test with α=0.05). The average unit mass "wet" extinction efficiency fluctuates when relative humidity is less than 40%, while it increases significantly when the relative humidity is between 40% and 90%. The existing humidity correction methods did not work in Chengdu area. The unit mass "wet" extinction coefficient appears to represent a non-stationary random sequence. Based on uncertainty analysis, a new method about the extinction coefficient humidity correction was proposed. It maintains statistical consistency with the unit mass "wet" extinction coefficient and the unit mass "dry" extinction coefficient, and achieves satisfying results in practical use.

Key words：Chengdu PM_2.5 concentration extinction coefficient hygroscopic growth model correction