title: Soil nitrite as a source of atmospheric HONO and OH radicals.
abstract: Hydroxyl radicals (OH) are a key species in atmospheric photochemistry. In the lower atmosphere, up to ~30% of the primary OH radical production is attributed to the photolysis of nitrous acid (HONO), and field observations suggest a large missing source of HONO. We show that soil nitrite can release HONO and explain the reported strength and diurnal variation of the missing source. Fertilized soils with low pH appear to be particularly strong sources of HONO and OH. Thus, agricultural activities and land-use changes may strongly influence the oxidizing capacity of the atmosphere. Because of the widespread occurrence of nitrite-producing microbes, the release of HONO from soil may also be important in natural environments, including forests and boreal regions.
authors.affiliation: Biogeochemistry Department, Max Planck Institute for Chemistry, Mainz 55020, Germany. h.su@mpic.de
authors.forename: Hang
authors.initials: H
authors.lastname: Su
authors.forename: Yafang
authors.initials: Y
authors.lastname: Cheng
authors.forename: Robert
authors.initials: R
authors.lastname: Oswald
authors.forename: Thomas
authors.initials: T
authors.lastname: Behrendt
authors.forename: Ivonne
authors.initials: I
authors.lastname: Trebs
authors.forename: Franz X
authors.initials: FX
authors.lastname: Meixner
authors.forename: Meinrat O
authors.initials: MO
authors.lastname: Andreae
authors.forename: Peng
authors.initials: P
authors.lastname: Cheng
authors.forename: Yuanhang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ulrich
authors.initials: U
authors.lastname: Pöschl
mesh_terms: D000383:Agriculture; D001272:Atmosphere / Q000737:chemistry*; D002940:Circadian Rhythm; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000032:analysis* / Q000737:chemistry; D009573:Nitrites / Q000737:chemistry* / Q000378:metabolism*; D009608:Nitrous Acid / Q000032:analysis* / Q000737:chemistry; D010084:Oxidation-Reduction; D010782:Photolysis; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D009573:Nitrites; D012987:Soil; D017665:Hydroxyl Radical; D009608:Nitrous Acid