Now, international researchers have used a technology originally developed by the US military to locate Soviet atomic tests by analysing tiny particles in the air blown across the Pacific by prevailing winds.
The model is now used widely for real-time wildfire smoke detection and forecasting, and to study stationary sources of anthropogenic emissions of greenhouse gases.
Satellite-based sensors showed that the smoke was from more than 3,000 active fires in Punjab and Haryana, its plume transported by prevailing winds to the foothills of the Himalaya and up to Kathmandu Valley.
“It was not just the open burning in Haryana and Punjab but also weather conditions that allowed for aerosols concentrated in the southern plains to be transported to Kathmandu and higher elevations,” says climate scientist Binod Pokharel, one of the authors of the recent paper in the journal Atmospheric Pollution Research.
The team consisting mainly of Nepali scientists deployed the tongue-twistingly named Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT), a computer model that computes air parcel trajectories to determine how far and in what direction pollutants will travel.
“Our main objective was to start a multilateral dialogue between countries in the region because while local solutions are important, air pollution is also a transboundary problem and needs committed leaders working together to develop and implement policies prioritising air pollution and mitigate its impact on public health,” adds Pokharel, who is Associate Professor at Tribhuvan University in Kathmandu.