广东省江门市是粤港澳大湾区重要节点城市，区位优势突出，开发空间广阔。随着当地交通业和建造业的快速发展，江门市空气质量明显下降，成为珠三角地区污染最严重的城市之一。
本研究对江门市 2008 年 10 月-11 月的大气水平能见度、颗粒物质量浓度和化学组成以及气象要素等内容进行了监测。观测期间，该地区大气水平能见度为 8.836±2.607km，能见度大于和小于 10km 时 PM 2.5 浓度分别为82.21±5.74μg · m -3 和 102.04±14.45μg · m -3 ，均高于国家二级标准。能见度与温度(0.573)和相对湿度(-0.554)相关性显著，高 PM 2.5 浓度在高湿度环境中更容易引起低能见度天气，气溶胶消光效应是削减能见度直接原因。
研究中还对该地气溶胶谱分布进行了测量，使用 Mie 散射模型计算了气溶胶等效复折射率，并模拟在不同混合态下消光系数。江门市大气气溶胶等效复折射率为 m=1.292(±0.045)-0.0060(±0.0020)i，日变化呈现“单谷型”，与散射系数和吸收系数变化规律相近。均匀内混模型模拟的散射系数与实际测量值更接近，外混模型模拟的吸收系数与实际更接近，说明气溶胶的混合状态介于两者之间，模拟值和测量值的差距随着相对湿度的升高而增大。

Jiangmen city in Guangdong province is an important node city in the Guangdong-Hong Kong-Macao greater bay area with prominent regional advantages and vast development space. With the rapid development of local transportation and construction industries, air quality has declined significantly, making it one of the most polluted cities in the Pearl River Delta region.
In this study, atmospheric horizontal visibility, particulate concentration, chemical composition and meteorological elements were monitored from October to November 2008 in Jiangmen city. We found that during the observation period, the atmospheric horizontal visibility was 8.836±2.607km. The PM 2.5  mass concentration was 82.21±5.74μg · m -3 and 102.04±14.45μg · m -3 when the visibility was greater than or less than 10km, respectively, which were all higher than the second national standard. Visibility is significantly correlated with temperature (0.573) and relative humidity (-0.554). High PM 2.5 concentration in high humidity environment is more likely to cause low visibility weather. Extinction effect of aerosols is the direct cause of reducing visibility.
The aerosol spectral distribution was also measured in this study. We used Mie scattering model to simulate the equivalent complex refractive index of aerosols and extinction coefficients in different mixed states. The equivalent complex refractive index of atmospheric aerosols in Jiangmen city is m=1.292(± 0.045)-0.0060(±0.0020)i. The daily variation of refractive index is "single valley", which is similar to the variation of scattering coefficient and absorption coefficient. The scattering coefficient simulated in the uniform internal mixing model is closer to the actual measured value, and the absorption coefficient simulated by the external mixing model is closer to the actual measured value. The model result indicated that the mixing state of aerosol is between the internal and external state, and the gap between the simulated value and the measured value increases with the increase of relative humidity.