Daytime isoprene nitrates under changing NO<sub><i>x</i></sub> and O<sub>3</sub>
<p>Organonitrates are important species in the atmosphere due to their impacts on NO<span class="inline-formula"><sub><i>x</i></sub></span>, HO<span class="inline-formula"><sub><i>x</i></sub></span>, an...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/23/8473/2023/acp-23-8473-2023.pdf |
| Summary: | <p>Organonitrates are important species in the atmosphere due to their impacts on NO<span class="inline-formula"><sub><i>x</i></sub></span>, HO<span class="inline-formula"><sub><i>x</i></sub></span>, and O<span class="inline-formula"><sub>3</sub></span> budgets, and their potential to contribute to secondary organic aerosol (SOA) mass. This work presents a steady-state modelling approach to assess the impacts of changes in NO<span class="inline-formula"><sub><i>x</i></sub></span> and O<span class="inline-formula"><sub>3</sub></span> concentrations on the organonitrates produced from
isoprene oxidation. The diverse formation pathways to isoprene organonitrates dictate the responses of different groups of organonitrates
to changes in O<span class="inline-formula"><sub>3</sub></span> and NO<span class="inline-formula"><sub><i>x</i></sub></span>. For example, organonitrates predominantly formed from the OH-initiated oxidation of isoprene favour
formation under lower-ozone and moderate-NO<span class="inline-formula"><sub><i>x</i></sub></span> concentrations, whereas
organonitrates formed via daytime NO<span class="inline-formula"><sub>3</sub></span> oxidation show the highest
formation under high-O<span class="inline-formula"><sub>3</sub></span> concentrations with little dependence on
NO<span class="inline-formula"><sub><i>x</i></sub></span> concentrations. Investigating the response of total organonitrates
reveals complex and nonlinear behaviour with implications that could inform
expectations of changes to organonitrate concentrations as efforts are made
to reduce NO<span class="inline-formula"><sub><i>x</i></sub></span> and O<span class="inline-formula"><sub>3</sub></span> concentrations, including a region of
NO<span class="inline-formula"><sub><i>x</i></sub></span>–O<span class="inline-formula"><sub>3</sub></span> space where total organonitrate concentration is relatively insensitive to changes in NO<span class="inline-formula"><sub><i>x</i></sub></span> and O<span class="inline-formula"><sub>3</sub></span>. These conclusions are further contextualised by estimating the volatility of the isoprene organonitrates revealing the potential for high concentrations of low-volatility species under high-ozone conditions.</p> |
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| ISSN: | 1680-7316 1680-7324 |