Terahertz wave -- evaluate emergency measures during red alert period

Beijing Municipal Environmental Protection Bureau announced the first-ever red alert for smog in China on Dec. 7th, 2015. PM2.5 monitoring of both concentrations and the sources of pollutants is of great significance for environmental departments and the public. Recently, scientists employed terahertz spectroscopy to investigate PM2.5 collected during the red alert period and in a haze condition without red alert. Sulfate types were different and metallic oxides were absent during the red alert period. Read more