Ground-Level Ozone Falling Faster Than Model Predicted

According to a study performed by Rice University and EPA’s Atmospheric Modeling and Analysis Division, research indicates ozone levels have dropped even beyond what was anticipated. This is especially true in the Northeast States where new regulations implemented over the last four years have effectively reduced air pollution by automobiles and industry.

From a chemical perspective, the ozone reduction is a nonlinear reaction when compared to NOx and hydrocarbon reductions. There seems to be some reactions that can’t be quantified, which have resulted in inaccurate predictions even when the best available meteorology models were used to predict ozone levels.

Cohan said that ”In the SIP Call, the researchers found the simulated drop in ozone was 4.6 ppb, while the observed drop was 8 ppb, a significant difference. Faster-than-expected reductions in NOx emissions may explain some but not all of that gap. The remaining gap may result from inaccuracies in how the model represents the chemistry and transport of air pollutants.”

This group study showed that regulatory modeling is slightly under-predicting the ozone reduction that was actually achieved.

“The goal of everyone in the process is to reach attainment in the most cost-effective manner possible, and we need accurate models to inform those decisions,” Cohan said.

Read more here: https://www.pollutiononline.com/doc/ground-level-ozone-falling-faster-than-model-predicted-0001?sectionCode=News&templateCode=EnhancedStandard&user=20&source=nl:36607

Categorised in: EPA