Relative importance of meteorological variables on air quality and role of boundary layer height

To gain insight on the meteorological effects of air pollution, we study the relative importance of surface meteorological variables and boundary layer height (BLH) on six major air pollutants according to the orders of variables being selected in a forward variable selection algorithm. It is found that there was a strong agreement in the orders of relative importance for the major pollutants among six major cities in North China, which implies regularities in the meteorological processes of air pollution in that region. In particular, PM2.5, PM10, SO2 and CO shared a common variable importance order and were mostly impacted by the dew point temperature and air pressure, while the NO2 and O-3 were mostly influenced by the boundary layer height (BLH) and temperature, respectively. We evaluate the impacts of BLH on the pollution levels given the surface meteorological variables. It is found that BLH can be well modeled by the surface meteorological variables. Thus, air quality assessment without using BLH would also produce adequate results.

Automated summary

The study found regularities in the meteorological processes of air pollution in six major cities in North China, with PM2.5, PM10, SO2, and CO being mainly influenced by dew point temperature and air pressure, and NO2 and O3 being mostly impacted by boundary layer height and temperature. The research also showed that boundary layer height could be accurately modeled using surface meteorological variables, indicating that air quality assessment without considering BLH would still yield satisfactory results.