Index > Authors> CCTVNEWS> Scientists show how temperatures affect China's smog

Scientists show how temperatures affect China's smog

Scientists take to the air to investigate China’s smog problem and discover how the temperature can make things worse.

As 10 cities in China issue red-level smog alerts, researchers at Shanghai Jiaotong University have wrapped up a five-year study in which they used unmanned aerial aircrafts to investigate air pollutants.

Scientists at the university created two versions of the aircraft, a helicopter and a small plane. Sensors onboard could collect data creating 3-dimensional graphs. The graphs displayed different colors for the levels of pollutants at different altitudes.

Normally temperature decreases the higher you go but under certain weather conditions it can actually get warmer as you go higher, termed ‘temperature inversion’. They found that temperature inversion – the increase in temperature with height - is actually one of the factors leading to smog.

Team leader Professor Peng Zhongren of the university says that from the ground to one kilometer high, normally the level of PM 2.5 particles would decrease with height. However, when a temperature inversion layer forms, it prevents the particles from being diffused.

"An inversion acts like a lid, trapping pollutants below it and allowing them to build up. If the sky is very hazy, or if sunsets are very red, there is likely an inversion somewhere in the lower atmosphere,” said Peng.

The team is already working with the Shanghai Environment Monitoring Center for further research as officials say using unmanned aerial aircrafts to monitor air quality compliments current methods.

In the past, the city's air quality monitoring stations were all ground-based. In 2013, researchers started using a balloon to monitor air pollution, but balloons lack flexibility.

While Peng’s team’s investigation into how the environment effects pollution levels will undoubtedly help tackle the problem of smog in the long run, it will be of little immediate comfort to people living in China’s eastern cities which are currently suffering from severe smog and haze.

Haze alerts continue to be issued in parts of China, including Beijing and Tianjin municipalities, as well as some provinces like Hebei, Anhui, Shandong, Jiangsu and Henan.

Heavy fog remains in the same areas, with visibility limited to 200 meters in some places, according to the China Meteorological Administration.

However the haze is forecast to recede starting from December 26 and it is the work of people like Peng that will make these forecasts even more accurate.