OPEN ACCESS

Articles online

Aerosol Pollution Characterization before Chinese New Year in Zhengzhou in 2014

Category: Aerosol and Atmospheric Chemistry

Volume: 19 | Issue: 6 | Pages: 1294-1306
DOI: 10.4209/aaqr.2018.06.0226
PDF

Export Citation:  RIS | BibTeX

Xiuli Wei 1, Huaqiao Gui1,3, Jianguo Liu1,3, Jie Zhang2, James Schwab2, Minguang Gao1

  • 1 Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
  • 2 Atmospheric Sciences Research Center, University at Albany, State University of New York, Albany and Wilmington, NY 12222, USA
  • 3 CAS Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China

Highlights

Measured the inorganic compounds in PM2.5 with FTIR in Zhengzhou.
The pollutions shrink was discussed.
The transportation was the main reason for the high sulfate concentration in Stage 2.
Nitrate formed through homogeneous gas-phase reactions in Stage 2.
The hygroscopic growth of particles may be the primary reason for the high PM2.5 in Stage 3.


Abstract

Fourier-transform infrared (FTIR) spectroscopy is a useful and nondestructive method for measuring the current atmospheric concentrations of inorganic compounds (sulfate, nitrate, and ammonium) and has been extensively used for environmental monitoring since the 1980s. In this study, we used FTIR spectroscopy to measure the inorganic compounds in particulate matter with a diameter of less than 2.5 µm and combined the data of gaseous pollutants (NO2 and SO2) to analyze the inorganic compounds in PM2.5 from January 24 to January 31, 2014, in Zhengzhou. The measurement period was divided into three pollution stages. During Stage 1 (January 24–26), the low-pollution stage, wind from the east of Zhengzhou caused the pollutants to rapidly disperse and the haze to clear. During Stage 2 (January 26 to the noon of January 30), transported emissions were the main contributor to the high sulfate concentration, as indicated by the poor correlation between the sulfur oxidation ratio (SOR) and the SO42– concentration (R2 = 0.45). Nitrate was formed through homogeneous gas-phase reactions of NO2 with OH or O3, resulting in HNO3 in the PM2.5, as indicated by the good correlation between the nitrogen oxidation ratio (NOR) and the NO3 concentration (R2 = 0.91). During Stage 3 (the afternoon of January 30 to January 31), the average concentration of the PM2.5 increased from approximately 140 µg m–3 to 260 µg m–3, and the concentrations of sulfate, nitrate, and ammonium decreased from 37.62 µg m–3, 56.63 µg m–3, and 34.63 µg m–3 to 32.14 µg m–3, 31.14 µg m–3, and 26.35 µg m–3, respectively. The high levels of PM2.5 during this stage may have been caused primarily by the hygroscopic growth of particles.

Keywords

FTIR Inorganic compounds PM2.5 Hygroscopic growth


Related Article

;