[Ozone Sensitivity Analysis and Emission Controls in Dezhou in Summer]

Area of Science:

• Atmospheric Chemistry and Air Pollution
• Environmental Modeling
• Ozone Pollution Dynamics

Background:

• Dezhou, China, experienced severe ozone pollution in summer 2018, with concentrations exceeding national standards for 60 days.
• The average daily 8-hour maximum ozone concentration was 176 μg·m⁻³, highlighting a significant air quality issue.

Purpose of the Study:

• To analyze ozone sensitivity to emissions and evaluate control strategies in Dezhou during the 2018 summer pollution episodes.
• To determine the dominant ozone formation regimes in urban and suburban areas.

Main Methods:

• Utilized the Weather Research and Forecasting (WRF) model coupled with the higher-order decoupled direct method (HDDM).
• Simulated ozone formation and response to emission changes using the WRF-CAMx model.

Main Results:

• Ozone formation was found to be strongly volatile organic compound (VOC)-limited in urban Dezhou.
• A transition regime (NOx and VOCs) was observed in suburban areas, with varying daily sensitivity values.
• VOC sensitivity was consistently positive, particularly high in June and August.

Conclusions:

• Prioritize VOC reduction in urban areas for effective ozone control.
• Recommend a 1:1 reduction ratio for NOx and VOC emissions in suburban areas for balanced control effectiveness.