Indirect contributions of global fires to surface ozone through ozone–vegetation feedback
<p>Fire is an important source of ozone (<span class="inline-formula">O<sub>3</sub></span>) precursors. The formation of surface <span class="inline-formula">O<sub>3</sub></span> can cause damage to vegetation and reduce stom...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2021-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/21/11531/2021/acp-21-11531-2021.pdf |
| Summary: | <p>Fire is an important source of ozone (<span class="inline-formula">O<sub>3</sub></span>) precursors. The formation of surface <span class="inline-formula">O<sub>3</sub></span> can cause damage to vegetation and reduce stomatal conductance. Such processes can feed back to inhibit dry deposition and indirectly enhance surface <span class="inline-formula">O<sub>3</sub></span>. Here, we apply a fully coupled chemistry–vegetation model to estimate the indirect contributions of global fires to surface <span class="inline-formula">O<sub>3</sub></span> through <span class="inline-formula">O<sub>3</sub></span>–vegetation feedback during
2005–2012. Fire emissions directly increase the global annual mean
<span class="inline-formula">O<sub>3</sub></span> by 1.2 <span class="inline-formula">ppbv</span> (5.0 %) with a maximum of
5.9 <span class="inline-formula">ppbv</span> (24.4 %) averaged over central Africa by emitting
a substantial number of precursors. Considering <span class="inline-formula">O<sub>3</sub></span>–vegetation
feedback, fires additionally increase surface <span class="inline-formula">O<sub>3</sub></span> by 0.5 <span class="inline-formula">ppbv</span>
averaged over the Amazon in October, 0.3 <span class="inline-formula">ppbv</span> averaged over southern
Asia in April, and 0.2 <span class="inline-formula">ppbv</span> averaged over central Africa in April.
During extreme <span class="inline-formula">O<sub>3</sub></span>–vegetation interactions, such a feedback can rise to
<span class="inline-formula">>0.6</span> <span class="inline-formula">ppbv</span> in these fire-prone areas. Moreover, large ratios of
indirect-to-direct fire <span class="inline-formula">O<sub>3</sub></span> are found in eastern China
(3.7 %) and the eastern US (2.0 %), where the high
ambient <span class="inline-formula">O<sub>3</sub></span> causes strong <span class="inline-formula">O<sub>3</sub></span>–vegetation interactions. With the likelihood of increasing fire risks in a warming climate, fires may promote
surface <span class="inline-formula">O<sub>3</sub></span> through both direct emissions and indirect
chemistry–vegetation feedbacks. Such indirect enhancement will cause
additional threats to public health and ecosystem productivity.</p> |
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| ISSN: | 1680-7316 1680-7324 |