Fast sulfate formation from oxidation of SO₂ by NO₂ and HONO observed in Beijing haze.

ABSTRACT: Severe events of wintertime particulate air pollution in Beijing (winter haze) are associated with high relative humidity (RH) and fast production of particulate sulfate from the oxidation of sulfur dioxide (SO₂) emitted by coal combustion. There has been considerable debate regarding the mechanism for SO₂ oxidation. Here we show evidence from field observations of a haze event that rapid oxidation of SO₂ by nitrogen dioxide (NO₂) and nitrous acid (HONO) takes place, the latter producing nitrous oxide (N₂O). Sulfate shifts to larger particle sizes during the event, indicative of fog/cloud processing. Fog and cloud readily form under winter haze conditions, leading to high liquid water contents with high pH (>5.5) from elevated ammonia.

SUBMITTER: Wang J 

PROVIDER: S-EPMC7275061 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature