Arid Zone Research ›› 2024, Vol. 41 ›› Issue (3): 375-386.doi: 10.13866/j.azr.2024.03.03

• Weather and Climate • Previous Articles     Next Articles

Characteristics and pollutant concentrations of persistent cold air pools in Lanzhou from 2013 to 2023

KANG Guoqiang(), MA Minjin(), CAO Yidan, CHEN Ran   

  1. College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, Gansu, China
  • Received:2023-10-01 Revised:2023-12-11 Online:2024-03-15 Published:2024-04-01

Abstract:

Persistent cold air pools (PCAPs) in valley cities lead to the prolonged accumulation of air pollutants, thereby affecting the lives and health of residents. In this study, sounding data and daily air quality data from January 2013 to November 2023 were used to calculate and statistically analyze the characteristics of PCAPs occurrences in the Lanzhou Valley. In addition, the impact of PCAPs intensity on changes in pollutant concentrations was explored, and variations in pollutant concentrations during PCAPs were analyzed and compared with concurrent dust aerosol pollution. Results indicate that from 2013 to 2023, 59 PCAPs occurred, lasting cumulative 197 days. During PCAPs, valley heat deficit and PM2.5 concentrations were 4.4 J·m-2 and 52.59 μg·m-3 higher, respectively, compared with non-PCAPs. The air quality index (AQI), SO2 concentration, NO2 concentration, CO concentration, and PM10 concentration increased by 70.37%, 144.3%, 84.3%, 156%, and 73.15%, respectively, whereas O3 concentration decreased by 60.89% during PCAPs. In PCAPs without dust aerosols, the average PM2.5:PM10 ratio was 0.58, whereas in PCAPs with dust aerosols, the average ratio was 0.31. During PCAPs with concurrent dust aerosols, PM2.5 concentration, PM10 concentration, AQI, and O3 concentration increased by 18.33%, 133.03%, 84.44%, and 8.5%, respectively. However, SO2 and CO concentrations decreased by 17.54% and 17.88%, respectively. These findings can serve as a reference for atmospheric pollution prevention and management strategies in the Lanzhou region.

Key words: persistent cold air pools, dust aerosol, valley cities, valley heat deficit, air pollution