The application supports air quality monitoring efforts in the Hindu Kush Himalayan region. It allows visualization of three atmospheric parameters – nitrogen dioxide (NO2), sulphur dioxide (SO2) and Aerosol Optical Depth (AOD) – for any chosen period and location. Users can specify a geographic area and time period to generate weekly or monthly mean values for the aforementioned parameters in the form of a chart.

The application carries out all the analyses in the Google Earth Engine, Google’s cloud computing platform for processing satellite imagery and other Earth observation data. It makes use of the latest NO2 and SO2 data from the Tropospheric Monitoring Instrument (TROPOMI) sensor onboard the Sentinel-5 Precursor (S5P) mission satellite and AOD data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra and Aqua satellites.

More information on the data layers used can be accessed from the links below:

• Sentinel-5P Nitrogen Dioxide - Tropospheric Vertical Column Density
• Sentinel-5P Sulphur Dioxide - SO₂ vertical column density at ground level
• MODIS Terra and Aqua combined Multi-angle Implementation of Atmospheric Correction (MAIAC) Land Aerosol Optical Depth (AOD)

The Regional Database System Initiative (RDS) at ICIMOD developed the Air Quality Explorer for the HKH. The Initiative’s primary objective is to promote availability and accessibility of scientific data to support evidence-based decision making in the HKH region. For more on the RDS, visit https://rds.icimod.org.