Enable accurate measurement of the concentration of nitrogen dioxide (NO2) in the atmosphere, a precursor of secondary fine particle and ozone

- KRISS developed 'photolytic NO2 monitor' to selectively detect NO2 -

Researchers from the Center for Gas Analysis have developed a photolytic NO2 monitor that can accurately measure NO2, which is a precursor of secondary fine particle and ozone.

The team developed and localized a photolytic NO2 monitor that can accurately measure the concentration of NO2 in the atmosphere using a photolytic converter coupled with chemiluminescence method. In addition, it has shown that the atmospheric NO2 is overestimated by 20.4 % annually through comparison with the existing measurement method.

Due to the importance of NO2 to human health and the atmosphere, NO2 was designated as one of the Korean Environmental Agency’s “criteria pollutants”. To measure NO2 using chemiluminescence method, NO2 has to be converted to nitric oxide(NO) using a converter. In this conversion process, a molybdenum converter has been widely used. Because molybdenum converter can convert not only NO2 but also other nitrogen oxides into NO, NO2 can be overestimated. However, quantitative determination of overestimation by molybdenum converter has not been made in Korea.

Dr. Jinsang Jung and Mr. Jaeyong Lee have developed a photolytic NO2 monitor that uses a photolytic converter in view of the fact that only NO2 is decomposed into NO when it is exposed to ultraviolet light (UV).

This instrument can selectively convert NO2 to NO by UV LED with a center wavelength of 395 nm. Because the photolytic converter is almost free from interferences, real NO2 concentration can be accurately measured by comparing converted NO and natural NO in the atmosphere.