Abstract
The role of the atmosphere in the biogeochemical cycle of phosphorus (P) is generally associated with the emission of soil dust, sea-salt particles, bioaerosols and industrial aerosols. Quite independently, a reduced gaseous phosphorus compound (phosphine, PH3) was measured over various sources such as marshes and sewage plants and also in the global troposphere. Given that phosphine is a reactive gas that rapidly yields low-volatility phosphoric acid in the atmosphere, secondary aerosol formation can be an important sink that has never been considered in the global phosphorus cycle. In our study we present mass size-distribution measurements of phosphorus in aerosol samples collected at two locations in Hungary. The bimodal size distribution of phosphorus indicated two distinct formation mechanisms in the fine (d < 1 µm) and coarse modes (d > 1 µm). As expected, the mass concentration of phosphorus was dominated by the coarse particles; the contribution of fine mode phosphorus to the total was in the range of 11–61% (median 19%). The contribution of biomass burning and to a lesser extent bioaerosols to the fine mode phosphorus was inferred from measured ambient potassium (K) concentrations and P/K ratios reported for biomass smoke. It was found that biomass burning accounted for only a small fraction of fine mode phosphorus, the rest of which likely formed as secondary aerosol component from gaseous phosphine. Secondary aerosol phosphorus can be even more important in providing this essential nutrient for remote ecosystems because it is associated with fine aerosol particles which have longer residence time and thus are more prone to long-range atmospheric transport than coarse primary particles.
Highlights
The biogeochemical cycle of phosphorus is mainly restricted to the flow of inorganic phosphorus in the lithosphere and that of organic phosphorus between the lithosphere, biosphere, and hydrosphere (Smil, 2000; Liu, 2008)
It was found that biomass burning accounted for only a small fraction of fine mode phosphorus, the rest of which likely formed as secondary aerosol component from gaseous phosphine
Potassium is commonly used as a tracer element for biomass burning since all plants contain potassium a part of which is emitted with submicron smoke particle
Summary
The biogeochemical cycle of phosphorus is mainly restricted to the flow of inorganic phosphorus in the lithosphere and that of organic phosphorus between the lithosphere, biosphere, and hydrosphere (Smil, 2000; Liu, 2008). The atmospheric presence and transport of phosphorus was predominantly linked to soil dust, sea-salt particles, bioaerosols and industrial aerosols (Graham and Duce, 1979; Smil, 2000). These primary sources all yield mainly coarse particles (with aerodynamic diameter larger than 1 μm) with relatively short atmospheric. The rate constant of phosphine oxidation by atomic oxygen was measured to be 5 × 10−11 cm3/s (Nava and Stief, 1989). The most likely oxidation pathway is the reaction with OH-radicals, with a rate constant of 1.4 × 10−11 cm3/s (Frank and Rippen, 1987).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
