Rapid urbanization expands the vertical space of cities, which changes urban micro-climate and the transport of air pollutants. Due to the construction of skyscrapers, the vertical activity range of people has reached as high as hundreds of meters. The changes in the vertical distribution of air pollutants may affect urban residents' health, however, the number of empirical studies on this subject was small and few data were available. 

In a recent study led by Dr. LI Chunlin and Dr. LIU Miao from the Landscape Ecology Research Group of the Institute of Applied Ecology (IAE) of the Chinese Academy of Sciences (CAS), the researchers investigated the vertical characteristics (0 - 120 m) of air pollutant concentrations (SO₂, NO₂, PM₁, PM_2.5 and PM₁₀) using an unmanned aerial vehicle (UAV) equipped with sensors along a sampling belt in the built-up area of Shenyang, an old industrial base in China, capital of Liaoning Province and high-end manufacturing base today.

The researchers found that all five air pollutants especially atmospheric particulate matters (PM₁, PM_2.5 and PM10) were concentrated near the ground. The five air pollutants, PM10, PM2.5, PM1, NO2 and SO2, decreased in concentration with increasing height, in the order from the largest rate to the smallest rate.

The study shows that unmanned aerial vehicles can greatly promote air pollution research.

This study, funded by the National Natural Science Foundation of China and the Youth Innovation Promotion Association of CAS, has been published in Sustainable Cities and Society entitled "Investigating the vertical distribution patterns of urban air pollution based on unmanned aerial vehicle gradient monitoring."