The sampling instrument is a low flow aerosol sampler with a collection rate of 16.7 L · min-1. The filter membrane uses a 47mm diameter quartz fiber filter membrane and is collected every 7 days for 48 hours; The detection instruments include: a thermal optical carbon analyzer for detecting EC and OC, an 881 ion chromatography system for detecting common anions and cations, a dual beam ultraviolet visible (UV vis) spectrometer for measuring the UV visible absorption spectrum of the sample in the wavelength range of 200-900 nm, a fluorescence spectrometer for scanning the sample to obtain a three-dimensional excitation emission matrix fluorescence spectrum, a total organic carbon analyzer for detecting WSOC, and a high-resolution time-of-flight aerosol mass spectrometer (HR ToF AMS) for obtaining chemical information of organic aerosols; The meteorological data comes from Vantage Pro2 automatic weather station

HR ToF AMS data processing uses standard data analysis software Igor Pro 6.37, which includes standard data processing toolkits SQUIRREL (v1.56) and PIKA (v1.15C); The component factors of organic aerosols are obtained through orthogonal matrix factor (PMF) analysis; The mass concentration of organic matter (OM) is calculated using the formula OM=OC * (OM/OC), where OC is the mass concentration of OC measured by a thermal optical carbon analyzer and OM/OC is the ratio of 2.1 obtained by PMF source apportionment; Other data are processed using conventional data processing methods to obtain mean and other information

The instrument is calibrated before testing the sample to ensure data accuracy