Compound heat wave and PM2.5 pollution episodes in U.S. cities

TL;DR

This paper investigates the characteristics and regional differences of heat waves, air pollution episodes, and their compound events in U.S. cities and rural areas using high-resolution datasets.

Contribution

It provides a detailed comparison of heat waves, pollution episodes, and their combinations across urban and rural areas in different U.S. regions, highlighting regional variations.

Findings

Heat waves are most frequent and intense in the West and Southwest.

Air pollution episodes are most frequent and long-lasting in the Northeast, Ohio Valley, and Southeast.

Compound events are more impacted by heat waves than pollution episodes in regions with prominent heat waves.

Abstract

This study analyzes heat waves (HWs), air pollution (AP) episodes, and compound HW and AP events (CE) in the urban environment and provides a comparison between events in urban areas (UAs) and rural areas (RAs). A 1-km gridded daily minimum temperature dataset and a 1-km gridded daily PM2.5 concentration dataset were used along with geospatial data to characterize events by their frequency, intensity in heat, intensity in pollution, and duration. The greatest differences between UAs and RAs in frequency, heat intensity, pollution intensity, and duration for all events were seen in the West and Southwest regions. For both UAs and RAs, it was found that HWs were the most frequent, intense, and longest lasting in the West and Southwest regions, AP episodes were the most frequent and longest lasting in the Northeast, Ohio Valley, and Southeast regions, and AP episodes were the most intense in the Northern Rockies and Plains and Upper Midwest regions. It was concluded that HWs (AP episodes) had a greater impact on CEs than AP episodes (HWs) in regions with more prominent HWs (AP episodes).