02 May 2023
 | 02 May 2023
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

Particulate-bound alkyl nitrate pollution and formation mechanisms in Beijing, China

Jiyuan Yang, Guoyang Lei, Jinfeng Zhu, Yutong Wu, Chang Liu, Kai Hu, Junsong Bao, Zitong Zhang, Weili Lin, and Jun Jin

Abstract. Fine particulate matter (PM2.5) samples were collected between November 2020 and October 2021 at the Minzu University of China in Beijing and the n-alkyl nitrate concentrations in the PM2.5 samples were determined to investigate n-alkyl nitrate pollution and formation mechanisms. C9–C16 n-alkyl nitrate standards were synthesized and the n-alkyl nitrate concentrations in PM2.5 were determined by gas chromatography triple quadrupole mass spectrometry. Temporal trends in and correlations between particulate-bound n-alkyl nitrate, ozone, PM2.5, and nitrogen dioxide concentrations were investigated to assess the relationships between particulate-bound n-alkyl nitrate concentrations and photochemical reactions and identify the n-alkyl nitrate formation mechanisms. The n-alkyl nitrate concentrations in the PM2.5 samples were 9.67–2730 pg/m3, and the mean was 578 pg/m3. The n-alkyl nitrate homologue group concentrations increased as the carbon chain length increased, i.e, long-chain n-alkyl nitrates contributed more than short-chain n-alkyl nitrates to the total n-alkyl nitrate concentrations in PM2.5. The n-alkyl nitrate concentrations clearly varied seasonally and diurnally, the concentrations decreasing in the order winter > spring > autumn > summer and the mean concentrations being higher at night than in the day. The particulate-bound n-alkyl nitrate and ozone concentrations significantly negatively correlated despite gas-phase alkyl nitrate and ozone concentrations previously being found to positively correlate. This indicated that long-chain alkyl nitrates may not be produced during photochemical reactions. The particulate-bound n-alkyl nitrate concentrations followed the same trends as and significantly positively correlated with the PM2.5 and nitrogen dioxide concentrations. Nitrogen dioxide is an important contributor of nitrates in particulate matter. This indicated that particulate-bound n-alkyl nitrates may form through reactions between alkanes and nitrates on particulate matter surfaces. Particulate-bound n-alkyl nitrates are important components of PM2.5 during haze events and strongly affect atmospheric visibility. Particulate-bound n-alkyl nitrates are secondary pollutants that strongly influence haze pollution.

Jiyuan Yang et al.

Status: open (until 03 Jul 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Jiyuan Yang et al.

Jiyuan Yang et al.


Total article views: 136 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
102 29 5 136 2 4
  • HTML: 102
  • PDF: 29
  • XML: 5
  • Total: 136
  • BibTeX: 2
  • EndNote: 4
Views and downloads (calculated since 02 May 2023)
Cumulative views and downloads (calculated since 02 May 2023)

Viewed (geographical distribution)

Total article views: 168 (including HTML, PDF, and XML) Thereof 168 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 06 Jun 2023
Short summary
The atmospheric pollution and formation mechanisms of particulate-bound alkyl nitrate in Beijing were studied. Long-chain n-alkyl nitrates contributed more to the total n-alkyl nitrate in PM2.5. Long-chain n-alkyl nitrates negatively correlated with O3 but positively correlated with PM2.5 and NO2, so they may not be produced during photochemical reactions but form through reactions between alkanes and nitrates on PM surfaces. Particulate-bound n-alkyl nitrates strongly influence haze pollution.