The combination of Google Scholar and sci-hub.se is pretty great:
(2021) Sources and dynamics of submicron aerosol during the autumn onset of the air pollution season in Delhi, India
> "Local sources of primary PM in Delhi include transportation, domestic biomass and trash burning, cooking, and industrial and construction activities. Delhi is also downwind of many agricultural states such as Punjab and Haryana, which can be a source of PM from agricultural burning. Delhi experiences cool winters with shallow boundary layer heights and frequent temperature inversions, which trap
pollutants within the boundary layer causing especially polluted conditions."
It's pretty seasonal, with the end-of-harvest agricultural burning seeming to be the biggest culprit.
Interestingly, California passed a law 20 years ago banning agricultural burning in the Central Valley (one of the worst air quality regions in the USA), but only started to enforce it last year. As ever, it's about cost: chipping up ag waste and composting it back into soil costs more than just burning it, cutting into profit margins for Big Ag.
I lived near Salt Lake City for a few years, and occasionally (being a city built in what is effectively a giant bowl) you'd see inversions there. It was insane. Warnings not to go outside if you don't have to, visibility absolutely enters the gutter, and it can last days or weeks.
Utah has pretty damn clean air normally as far as I can tell. I couldn't imagine how much worse it would be in Delhi. I really hope they can get their air cleaned up, but it's hard to get people to give a shit about something like that when they don't earn enough to even know if they'll eat every day.
(2021) Sources and dynamics of submicron aerosol during the autumn onset of the air pollution season in Delhi, India
> "Local sources of primary PM in Delhi include transportation, domestic biomass and trash burning, cooking, and industrial and construction activities. Delhi is also downwind of many agricultural states such as Punjab and Haryana, which can be a source of PM from agricultural burning. Delhi experiences cool winters with shallow boundary layer heights and frequent temperature inversions, which trap pollutants within the boundary layer causing especially polluted conditions."
It's pretty seasonal, with the end-of-harvest agricultural burning seeming to be the biggest culprit.
Interestingly, California passed a law 20 years ago banning agricultural burning in the Central Valley (one of the worst air quality regions in the USA), but only started to enforce it last year. As ever, it's about cost: chipping up ag waste and composting it back into soil costs more than just burning it, cutting into profit margins for Big Ag.
https://www.fresnobee.com/news/business/agriculture/article2...