Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea
The Dead Sea is an excellent natural laboratory for the investigation of Reactive Bromine Species (RBS) chemistry, due to the high RBS levels observed in this area, combined with anthropogenic air pollutants up to several ppb. The present study investigated the basic chemical mechanism of RBS at the...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2006-01-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/6/5589/2006/acp-6-5589-2006.pdf |
| _version_ | 1830462269309321216 |
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| author | E. Tas M. Peleg D. U. Pedersen V. Matveev A. Pour Biazar M. Luria |
| author_facet | E. Tas M. Peleg D. U. Pedersen V. Matveev A. Pour Biazar M. Luria |
| author_sort | E. Tas |
| collection | DOAJ |
| description | The Dead Sea is an excellent natural laboratory for the investigation of Reactive Bromine Species (RBS) chemistry, due to the high RBS levels observed in this area, combined with anthropogenic air pollutants up to several ppb. The present study investigated the basic chemical mechanism of RBS at the Dead Sea using a numerical one-dimensional chemical model. Simulations were based on data obtained from comprehensive measurements performed at sites along the Dead Sea. The simulations showed that the high BrO levels measured frequently at the Dead Sea could only partially be attributed to the highly concentrated Br− present in the Dead Sea water. Furthermore, the RBS activity at the Dead Sea cannot solely be explained by a pure gas phase mechanism. This paper presents a chemical mechanism which can account for the observed chemical activity at the Dead Sea, with the addition of only two heterogeneous processes: the "Bromine Explosion" mechanism and the heterogeneous decomposition of BrONO<sub>2</sub>. Ozone frequently dropped below a threshold value of ~1 to 2 ppbv at the Dead Sea evaporation ponds, and in such cases, O<sub>3</sub> became a limiting factor for the production of BrO<sub>x</sub> (BrO+Br). The entrainment of O<sub>3</sub> fluxes into the evaporation ponds was found to be essential for the continuation of RBS activity, and to be the main reason for the jagged diurnal pattern of BrO observed in the Dead Sea area, and for the positive correlation observed between BrO and O<sub>3</sub> at low O<sub>3</sub> concentrations. The present study has shown that the heterogeneous decomposition of BrONO<sub>2</sub> has a great potential to affect the RBS activity in areas influenced by anthropogenic emissions, mainly due to the positive correlation between the rate of this process and the levels of NO<sub>2</sub>. Further investigation of the influence of the decomposition of BrONO<sub>2</sub> may be especially important in understanding the RBS activity at mid-latitudes. |
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| format | Article |
| id | doaj.art-efa03da8d7df4870a45c3f74eb605d39 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-21T11:42:53Z |
| publishDate | 2006-01-01 |
| publisher | Copernicus Publications |
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| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-efa03da8d7df4870a45c3f74eb605d392022-12-21T19:05:15ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242006-01-0161255895604Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead SeaE. TasM. PelegD. U. PedersenV. MatveevA. Pour BiazarM. LuriaThe Dead Sea is an excellent natural laboratory for the investigation of Reactive Bromine Species (RBS) chemistry, due to the high RBS levels observed in this area, combined with anthropogenic air pollutants up to several ppb. The present study investigated the basic chemical mechanism of RBS at the Dead Sea using a numerical one-dimensional chemical model. Simulations were based on data obtained from comprehensive measurements performed at sites along the Dead Sea. The simulations showed that the high BrO levels measured frequently at the Dead Sea could only partially be attributed to the highly concentrated Br− present in the Dead Sea water. Furthermore, the RBS activity at the Dead Sea cannot solely be explained by a pure gas phase mechanism. This paper presents a chemical mechanism which can account for the observed chemical activity at the Dead Sea, with the addition of only two heterogeneous processes: the "Bromine Explosion" mechanism and the heterogeneous decomposition of BrONO<sub>2</sub>. Ozone frequently dropped below a threshold value of ~1 to 2 ppbv at the Dead Sea evaporation ponds, and in such cases, O<sub>3</sub> became a limiting factor for the production of BrO<sub>x</sub> (BrO+Br). The entrainment of O<sub>3</sub> fluxes into the evaporation ponds was found to be essential for the continuation of RBS activity, and to be the main reason for the jagged diurnal pattern of BrO observed in the Dead Sea area, and for the positive correlation observed between BrO and O<sub>3</sub> at low O<sub>3</sub> concentrations. The present study has shown that the heterogeneous decomposition of BrONO<sub>2</sub> has a great potential to affect the RBS activity in areas influenced by anthropogenic emissions, mainly due to the positive correlation between the rate of this process and the levels of NO<sub>2</sub>. Further investigation of the influence of the decomposition of BrONO<sub>2</sub> may be especially important in understanding the RBS activity at mid-latitudes.http://www.atmos-chem-phys.net/6/5589/2006/acp-6-5589-2006.pdf |
| spellingShingle | E. Tas M. Peleg D. U. Pedersen V. Matveev A. Pour Biazar M. Luria Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea Atmospheric Chemistry and Physics |
| title | Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea |
| title_full | Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea |
| title_fullStr | Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea |
| title_full_unstemmed | Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea |
| title_short | Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea |
| title_sort | measurement based modeling of bromine chemistry in the boundary layer 1 bromine chemistry at the dead sea |
| url | http://www.atmos-chem-phys.net/6/5589/2006/acp-6-5589-2006.pdf |
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