title: Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.
abstract: Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality.
authors.affiliation: Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720, USA.
authors.forename: P Y
authors.initials: PY
authors.lastname: Oikawa
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: C
authors.identifier: http://orcid.org/0000-0002-6182-6856
authors.initials: C
authors.lastname: Ge
authors.affiliation: Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Eberwein
authors.affiliation: Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA.
authors.forename: L L
authors.initials: LL
authors.lastname: Liang
authors.affiliation: Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Allsman
authors.affiliation: Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Grantz
authors.affiliation: Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Jenerette
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D000397:Air Pollution / Q000032:analysis*; D002140:California; D005308:Fertilizers / Q000032:analysis; D006358:Hot Temperature; D009584:Nitrogen / Q000737:chemistry; D009589:Nitrogen Oxides / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D045868:Sorghum
chemical_list: D000393:Air Pollutants; D005308:Fertilizers; D009589:Nitrogen Oxides; D012987:Soil; D009584:Nitrogen