Observational-based assessment of contributions to maximum ozone concentrations in the western United States.

Archived Ozone Design Values (ODVs) provide smoothed temporal records of maximum ozone concentrations impacting monitoring sites throughout the US. Utilizing time series of ODVs recorded at sites along the US West Coast, we separately estimate ODV contributions from US background ozone and from production driven by US anthropogenic precursor emissions. Sondes launched from Trinidad Head in northern California measure the vertical distribution of baseline ozone transported ashore from the Pacific; this profile is reflected in the increase of the US background ODV contribution with monitoring site elevation in both rural and urban areas.

Long-term baseline ozone changes in the Western US: A synthesis of analyses.

Quantification of the magnitude and long-term changes in ozone concentrations transported into the U.S. is important for effective air quality policy development.

On the changes in surface ozone over the twenty-first century: sensitivity to changes in surface temperature and chemical mechanisms.

In this study, we show using a state-of-the-art Earth system model, UKESM1, that emissions and climate scenario depending, there could be large changes in surface ozone by the end of the twenty-first century, with unprecedentedly large increases over South and East Asia. We also show that statistical modelling of the trends in future ozone works well in reproducing the model output between 1900 and 2050. However, beyond 2050, and especially under large climate change scenarios, the statistical model results are in poorer agreement with the fully interactive Earth system model output.

Intercomparison of chemical mechanisms for air quality policy formulation and assessment under North American conditions.

Unlabelled: The intercomparison of seven chemical mechanisms for their suitability for air quality policy formulation and assessment is described. Box modeling techniques were employed using 44 sets of background environmental conditions covering North America to constrain the chemical development of the longer lived species. The selected mechanisms were modified to enable an unbiased assessment of the adequacy of the parameterizations of photochemical ozone production from volatile organic compound (VOC) oxidation in the presence of NO.

Regional and global impacts of Criegee intermediates on atmospheric sulphuric acid concentrations and first steps of aerosol formation.

Carbonyl oxides ("Criegee intermediates"), formed in the ozonolysis of alkenes, are key species in tropospheric oxidation of organic molecules and their decomposition provides a non-photolytic source of OH in the atmosphere (Johnson and Marston, Chem. Soc. Rev.