How air pollution is measured in Ulaanbaatar : four different sources, two different methods
While Ulaanbaatar in known for its air pollution episodes during the winter months, this article shows the challenges raised by air quality data produced according to the new Mongolian standards.
The article points that in October 2018, the Mongolian Ministry of Environment and Tourism changed its method of calculating the Air Quality Index (AQI). When compared to the data produced by the international air quality monitoring sites in Ulaanbaatar (which use the US EPA reporting standards), the new Mongolian standard seems to smooth out the peaks (as it uses 3-hour means instead of 1-hour means as before) and makes hourly values seem lower. Furthermore, it uses physical value breakpoints to construct its AQI that are far lower than the US EPA standards. For instance, the US EPA considers that air quality is “good” up to 12 µg/m3 PM2.5, while the Mongolian AQI goes up to 35 µg/m3. Finally, concentrations values are no longer made available by Mongolian authorities, who only publish the AQI. This raises serious questions of transparency and can hinder the work of researchers and open data platforms who no longer have access to reliable concentration data.
In light of the above facts, the author argues that caution should be taken when analysing data on air pollution trends in Ulaanbaatar.
Author : Robert Ritz