• Question: is the brown cloud a natural occurance?

    Asked by phaysee to Alison, Artem, Caroline, John, Gunther on 11 Jun 2012.
    • Photo: Artem Evdokimov

      Artem Evdokimov answered on 11 Jun 2012:

      Are you referring to pollution clouds?

      Sometimes they can be, for example after a volcanic eruption. But I bet mostly they’re not…

    • Photo: John Short

      John Short answered on 12 Jun 2012:

      If you are referring to the Asian Brown cloud, that covers India, Pakistan and and Bangladesh is caused is created by a range of airborne particles and pollutants from combustion (e.g., woodfires, cars, and factories), biomass burning (such as residential cooking and agricultural burning) and industrial processes with incomplete burning. The cloud is associated with the winter monsoon (November/December to April) during which there is no rain to wash pollutants from the air.

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