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Observed suppression of ozone formation at extremely high temperatures due to chemical and biophysical feedbacks

2010; National Academy of Sciences; Volume: 107; Issue: 46 Linguagem: Inglês

10.1073/pnas.1008336107

1091-6490

Allison L. Steiner, Adam J. Davis, Sanford Sillman, R. C. Owen, A. M. Michalak, Arlene M. Fiore,

Air Quality and Health Impacts

Ground level ozone concentrations ([O 3 ]) typically show a direct linear relationship with surface air temperature. Three decades of California measurements provide evidence of a statistically significant change in the ozone-temperature slope (Δ m O3- T ) under extremely high temperatures (> 312 K). This Δ m O3- T leads to a plateau or decrease in [O 3 ], reflecting the diminished role of nitrogen oxide sequestration by peroxyacetyl nitrates and reduced biogenic isoprene emissions at high temperatures. Despite inclusion of these processes in global and regional chemistry-climate models, a statistically significant change in Δ m O3- T has not been noted in prior studies. Future climate projections suggest a more frequent and spatially widespread occurrence of this Δ m O3- T response, confounding predictions of extreme ozone events based on the historically observed linear relationship.