Investigating the impact of Glyoxal retrieval from MAX-DOAS observations during haze and non-haze conditions in Beijing

Zeeshan Javed; Cheng Liu; Muhammad Fahim Khokhar; Chengzhi Xing; Wei Tan; Muhammad Ahmed Subhani; Abdul Rehman; Aimon Tanvir

doi:10.1016/j.jes.2019.01.008

Investigating the impact of Glyoxal retrieval from MAX-DOAS observations during haze and non-haze conditions in Beijing

J Environ Sci (China). 2019 Jun:80:296-305. doi: 10.1016/j.jes.2019.01.008. Epub 2019 Jan 22.

Authors

Zeeshan Javed¹, Cheng Liu², Muhammad Fahim Khokhar³, Chengzhi Xing⁴, Wei Tan⁵, Muhammad Ahmed Subhani⁶, Abdul Rehman⁴, Aimon Tanvir⁶

Affiliations

¹ School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China. Electronic address: zeeshan@mail.ustc.edu.cn.
² School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China; Anhui Province Key Laboratory of Polar Environment and Global Change, USTC, Hefei 230026, China. Electronic address: chliu81@ustc.edu.cn.
³ Institute of Environmental Sciences and Engineering, National University of Sciences and Technology, Islamabad 44000, Pakistan. Electronic address: khokhar@iese.nust.edu.pk.
⁴ School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
⁵ Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
⁶ Institute of Environmental Sciences and Engineering, National University of Sciences and Technology, Islamabad 44000, Pakistan.

PMID: 30952347
DOI: 10.1016/j.jes.2019.01.008

Abstract

This study presents the Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements for Glyoxal (CHOCHO) in Beijing, China (39.95°N, 116.32°E). CHOCHO is the smallest compound of di-carbonyl group. As a primary sink of CHOCHO, its photolysis with NOx (oxides of nitrogen) results in the production of tropospheric ozone. Therefore, the focus of CHOCHO DOAS measurements is increasing in trend. We did the measurements from 09 May 2017 to 09 September 2017. The study was conducted to compare different retrieval settings in order to reveal best DOAS fit settings for CHOCHO; furthermore, effect of haze and non-haze days on CHOCHO concentration was examined. The root mean square of residual and Differential Slant Column density (dSCD) error was reduced when measurements were done with lower wavelength limit around 432-438 nm and upper intervals around 455-460 nm. Thus, lower wavelength intervals around 432-438 nm and upper intervals around 457-460 nm were best for the retrieval of dSCDs for CHOCHO. Meteorological conditions like haze or non-haze days did not have significant effect on DOAS fit parameters. The CHOCHO vertical column densities range from 1.33E+14 to 9.77E+14 molecules/cm² during the study period with average of 6.16E+14 molecules/cm². The results indicated that during haze days CHOCHO concentration was higher because of lower rate of photolysis and atmospheric oxidation potential. Our results did not show any significant weekend effect on CHOCHO atmospheric concentration.

Keywords: DOAS; Glyoxal; Haze days; Photolysis; Retrieval settings.

MeSH terms

Air Pollutants / analysis*
Beijing
China
Environmental Monitoring / methods*
Glyoxal / analysis*
Spectrum Analysis

Substances

Air Pollutants
Glyoxal