Researchers in Shanghai have developed a method to use unmanned aerial vehicles to monitor the concentration of PM2.5 at high attitudes in the Yangtze River Delta.

A team from Shanghai Jiao Tong University collected three-dimensional data to map out how the airborne pollutants move in the atmosphere.

PM2.5 refers to airborne particles less than 2.5 microns in diameter that harm health.

"The existing monitoring mainly focuses on ground-level pollutants. Very little monitoring is carried out at a higher altitude. With such ground-based monitoring, it is difficult for us to clearly understand patterns in the way haze arises and dissipates," said Peng Zhongren, a professor at Shanghai Jiao Tong University.

In 2011, Peng and his research team started to collect three-dimensional distribution data of PM2.5 and other airborne pollutants.

The preliminary studies show that an inversion layer, where a layer of warmer air moves over a layer of colder air, prevents the vertical diffusion of pollutants and increases the concentration of PM2.5 near the ground.

This provides the conditions for the formation of haze, Peng said.

Next, the research team will obtain more data to study how the inversion layer contributes to the accumulation of PM2.5 and the formation of haze, Peng said.

"We will collect more specific data, which will help us understand the change of airborne pollutants in different weather and seasons," he said.

Peng's team also carried out monitoring and analysis on the three-dimensional distribution and change in traffic pollutants around bridges and other three-dimensional structures with the assistance of their drone. They found that the concentration of PM2.5 changed with height.

"These initial findings provide guidance for residents who live in high-rise buildings alongside roads, and also works as a reference for urban road planning and architectural layout," Peng said.

wanghongyi@chinadaily.com.cn

(China Daily 12/30/2015 page5)