A large atomic chlorine source inferred from mid-continental reactive nitrogen chemistry
| Autor: | Joel A. Thornton, Glenn M. Wolfe, John S. Holloway, Patricia K. Quinn, James P. Kercher, J. Cozic, Nicholas L. Wagner, Ann M. Middlebrook, William P. Dubé, Theran P. Riedel, Becky Alexander, Steven S. Brown |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
inorganic chemicals
Colorado Time Factors Meteorology Reactive nitrogen Nitrogen chemistry.chemical_element Chloride Methane chemistry.chemical_compound polycyclic compounds Chlorine medicine Stratosphere Nitrites Aerosols Multidisciplinary Atmosphere Air Ozone depletion Models Chemical chemistry Environmental chemistry Atmospheric chemistry Nitrogen Oxides Nitrogen oxide medicine.drug |
| Zdroj: | Nature. 464:271-274 |
| ISSN: | 1476-4687 0028-0836 |
| Popis: | Chlorine atoms can profoundly affect the composition of the atmosphere. Notoriously, as chlorofluorocarbons, they were implicated in ozone depletion in the stratosphere. New observations suggest that chlorine may be a more potent force lower down in the atmosphere than was thought. The presence of gaseous chlorine atom precursors in the troposphere is generally considered a marine air phenomenon. But measurements made near Boulder, Colorado, reveal significant production of atmospheric nitryl chloride (ClNO2) in a continental setting, 1,400 km from the nearest coastline. This finding, incorporated into model studies, suggests that nitryl chloride production in the contiguous United States alone — probably arising from anthropogenic pollutants — is at a level similar to previous global estimates for marine regions. The presence of gaseous chlorine atom precursors within the troposphere was thought only to occur in marine areas but now nitryl chloride has been found at a distance of 1,400 km from the nearest coastline. A model study shows that the amount of nitryl chloride production in the continental USA alone is similar to previous global estimates for marine regions. A significant fraction of tropospheric chlorine atoms may arise directly from anthropogenic pollutants. Halogen atoms and oxides are highly reactive and can profoundly affect atmospheric composition. Chlorine atoms can decrease the lifetimes of gaseous elemental mercury1 and hydrocarbons such as the greenhouse gas methane2. Chlorine atoms also influence cycles that catalytically destroy or produce tropospheric ozone3, a greenhouse gas potentially toxic to plant and animal life. Conversion of inorganic chloride into gaseous chlorine atom precursors within the troposphere is generally considered a coastal or marine air phenomenon4. Here we report mid-continental observations of the chlorine atom precursor nitryl chloride at a distance of 1,400 km from the nearest coastline. We observe persistent and significant nitryl chloride production relative to the consumption of its nitrogen oxide precursors. Comparison of these findings to model predictions based on aerosol and precipitation composition data from long-term monitoring networks suggests nitryl chloride production in the contiguous USA alone is at a level similar to previous global estimates for coastal and marine regions5. We also suggest that a significant fraction of tropospheric chlorine atoms6 may arise directly from anthropogenic pollutants. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|