分别以干燥环境下的平均单位质量气溶胶消光系数和湿环境下烘干气溶胶的散射消光系数为基准,提出了与之对应的两种气溶胶消光吸湿增长因子f1(RH)和f2(RH)。基于成都市2017年10—12月浊度仪和黑碳仪的逐时观测资料以及该时段同时次的环境气象监测数据(大气能见度、相对湿度以及NO2和PM10的质量浓度),针对上述两种气溶胶消光吸湿增长因子进行了系统的对比分析。主要结论如下:1)f1(RH)和f2(RH)均能表征气溶胶吸湿性的光学效应,二者的判决系数为0.90(通过了α=0.01的显著性检验);2)多模型的比对结果表明,二次多项式函数较好地拟合了f1(RH)和f2(RH)随相对湿度的变化特征;3)f1(RH)和f2(RH)的均值之比随相对湿度的增加而增大。进一步研究指出,烘干气溶胶的散射消光系数对相对湿度变化的显著响应关系是导致f1(RH)和f2(RH)非一致性演化的根本原因。

Based on the references of average aerosol extinction coefficient per unit mass concentration in dry environment and baked aerosol scattering extinction coefficient in wet environment respectively, corresponding the two kinds of aerosol extinction hygroscopic growth factor, i.e. f₁(R_H) and f₂(R_H), had been proposed. By utilizing the hourly data from nephelometer and aethalometer, as well as the coincidental environmental and meteorological data, including atmospheric visibility, relative humidity, NO₂ mass concentration, and PM₁₀ mass concentration, in Chengdu from October 2017 to December 2017, the comparative study on the two kinds of aerosol extinction hygroscopic growth factors was systematically carried out. The results showed that both f₁(R_H) and f₂(R_H) could well characterize the optical effect of aerosol hygroscopicity, and their coefficient of determination was 0.90 (passed the significance test of α=0.01). By multi-model comparison, the quadratic polynomial function was proved to best fit the variation of both f₁(R_H) and f₂(R_H) with relative humidity. The ratio of average f₁(R_H) to average f₂(R_H) increased with the increase of relative humidity. Further research indicated that the significant response of baked aerosol scattering extinction coefficient to the variation of relative humidity was fundamental for the above inconsistency between f₁(R_H) and f₂(R_H).