1. Introductory information
Title of the dataset: Snowfall enhances secondary inorganic aerosol formation_Dataset
The dataset contains the series of the NR-PM2.5 (Org, NO3, NH4, SO4, Chl) chemical compositions concentrations, PM2.5 and gaseous pollutants mass concentrations, and meteorological observations in Beijing, China, from January 15 to March 6, 2019.
2. Methodological information
The mass concentration of PM2.5 was monitored by an R&P model 1400a Tapered Element Oscillating Microbalance (TEOM, Thermo Scientific Co., USA). The collocated gaseous species, including SO2, NOx, and O3, were measured by various gas analyzers (Thermo Scientific Co., USA). The chemical composition of non-refractory fine particles (NR-PM2.5) was measured by an Aerodyne online Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM) coupled with a PM2.5 cyclone to remove coarse particles larger than 2.5 m. The measured composition of particles included sulfate (SO4), nitrate (NO3), ammonium (NH4), chloride (Chl), and organic aerosols (Org). The Q-ACSM was operated with a mass spectrometer, at a scanning rate of 500 ms/amu from m/z of 10 to 140. The data was saved every two cycles, leading to a time resolution of approximately 5 min. The Q-ACSM was calibrated with ammonium nitrate and ammonium sulfate particles, using the methods described in Ng et al. [2011]. The sensitivity of the Q-ACSM were calibrated using the size-selected ammonium nitrate particles (300 nm), which were 6.94  10C11. The relative ionization efficiencies (RIEs) of ammonium and sulfate were determined as 4.51 and 1.86, respectively. The default RIE values were 1.4 for organics, 1.1 for nitrate, and 1.3 for chloride, respectively.
3. Data specific information
Full names and definitions (spell out abbreviated words) of column headings for tabular data
Non-refractory fine particles (NR-PM2.5), acsm_local_time (Beijing Time), sulfate (SO4), nitrate (NO3), ammonium (NH4), chloride (Chl), and organic aerosols (Org); sulfur dioxide (SO2), oxynitride (NOx), and ozone (O3); the units of measurement are ?g m-3. The meteorological contains temperature (T, ), relative humidity (RH, %), and precipitation (mm).
Definitions for codes or symbols used to record missing data is blank.
Specialized formats or abbreviations used: sulfate (SO4), nitrate (NO3), ammonium (NH4), chloride (Chl), and organic aerosols (Org); sulfur dioxide (SO2), oxynitride (NOx), and ozone (O3).
