Extreme ozone episodes in a major Mediterranean urban area
<p>This study analyses three extreme ozone (O<span class="inline-formula"><sub>3</sub></span>) episodes that occurred in Barcelona (NE Spain) during the summers of 2015, 2018, and 2019. These episodes exceeded the EU's hourly information threshold (180 &l...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2024-04-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/24/4827/2024/acp-24-4827-2024.pdf |
| Summary: | <p>This study analyses three extreme ozone (O<span class="inline-formula"><sub>3</sub></span>) episodes that occurred in Barcelona (NE Spain) during the summers of 2015, 2018, and 2019. These episodes exceeded the EU's hourly information threshold (180 <span class="inline-formula">µg</span> m<span class="inline-formula"><sup>−3</sup></span>) for the first time since at least the year 2000, raising concerns due to Barcelona's large population. By employing experimental data and various modelling tools, our main objective is to elucidate the underlying phenomena of these recent O<span class="inline-formula"><sub>3</sub></span> episodes and improve predictive capabilities. The findings indicate that the factors contributing to these occurrences are largely consistent across episodes. These factors, with estimated O<span class="inline-formula"><sub>3</sub></span> contributions specified for particular instances, comprise (i) initial O<span class="inline-formula"><sub>3</sub></span> accumulation in surrounding coastal areas; (ii) weekend occurrence, accompanied by the corresponding weekend effect (<span class="inline-formula">+</span>15 <span class="inline-formula">µg</span> m<span class="inline-formula"><sup>−3</sup></span>); and (iii) the prevalence of Tramontana meteorological conditions during above-normal temperatures, which (iv) force the convergence of multiregional polluted air masses to the city (<span class="inline-formula">+</span>45–65 <span class="inline-formula">µg</span> m<span class="inline-formula"><sup>−3</sup></span>). Major source areas include regions of southern France through the Gulf of Lion, the interior of the Mediterranean, and eastern Spanish coastal regions, including Barcelona's pollution plume. Some of these factors, which may manifest in the days preceding the episodes, are observable or can be anticipated. This study enhances understanding of the mechanisms driving extreme O<span class="inline-formula"><sub>3</sub></span> episodes recently observed in Barcelona and provides valuable insights for prediction.</p> |
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| ISSN: | 1680-7316 1680-7324 |