Activity-Weighted Assessment and Environmental Drivers of Compound Ozone-Heat Exposure Risk in Urban Outdoor Exercise...

Area of Science:

• Environmental Health
• Urban Planning
• Geospatial Analysis

Background:

• Urban outdoor exercise spaces are crucial for physical activity but expose users to air pollution and heat.
• Assessing combined environmental risks is essential for public health in urban settings.

Purpose of the Study:

• To develop an activity-weighted framework for assessing compound ozone-heat exposure risk in urban outdoor exercise spaces.
• To identify high-risk exercise spaces for targeted interventions.

Main Methods:

• Integrated mobile phone data, O3 estimates, land surface temperature (LST), land cover, road networks, and building morphology.
• Constructed a compound ozone-heat exposure risk index (COHER) using visitation frequency, O3, and LST.
• Employed XGBoost-SHAP for environmental correlate analysis.

Main Results:

• Visitation frequency, O3, and LST showed mismatched spatial patterns, necessitating compound assessment.
• 49 outdoor exercise spaces were identified as high-risk sites (top 10%).
• High-risk sites had greater visitation frequency and LST; O3 differences were minor.

Conclusions:

• The proposed framework effectively identifies priority outdoor exercise spaces for risk mitigation.
• Built-up intensity, building height variability, and airflow obstruction correlate with higher compound risk.
• This tool supports exposure-sensitive urban planning for public health.