Air Quality Issues Associated with Wildfire Events in the Indian Himalayan Region

In recent decades, the Indian Himalayan states have witnessed a notable surge in wildfires exacerbated by a confluence of anthropogenic and natural factors with the changing climate. While wildfires have long been a cause for concern, the associated air quality issues have garnered less attention than the winter smog resulting from stubble burning in North India. Noteworthy instances of North Indian wildfires occurred in 2016 and 2020, particularly impacting the state of Uttarakhand, where over 4000 hectares of forested land were engulfed. Beyond the immediate devastation caused by the fires, the dispersion of ashes and aerosols to adjacent Himalayan regions has become a pertinent concern. In this study, we utilize the NOAA-HYSPLIT model ensemble trajectories to illustrate the transport of wildfire pollutants vividly. A comparative analysis of the HYSPLIT model's forward trajectory with MERRA2 datasets reveals the transport of pollutants such as SO2EMBB (SO2 Biomass Burning Emissions), BCEMBB (Black Carbon Biomass Burning Emission), and BCSMASS (Black Carbon Surface Mass Concentration) as the wildfires progressed for 2016 and 2020 towards the Greater Himalayan region. Further abrupt peaks in BCSMASS, BCEMBB and SO2EMBB were noticed over the Greater Himalayan region, where the back trajectory projects to the fire ignition pixels as source points in the Uttarakhand region via FIRMS (Fire Information for Resource Management System) database. Noticeably, during the 2020 wildfire season, reanalysis datasets from ERA5 and NCEP-FNL show an abrupt variation of 4oC more compared to the normal skin temperature in non-wildfire seasons, whereas the 2016 wildfires were exacerbated by the heatwaves and El-Nino conditions in the Indian terrain. This alarming prospect parallels the 2019 Arctic Circle fire, emphasizing the urgent need for comprehensive strategies to mitigate the escalating impacts of wildfires on the fragile Himalayan ecosystem.