XToll

What is XToll?

XToll is an interactive dashboard that visualizes county-level rankings for wildfire smoke-, heat-, cold-, drought-, and flood-related and total extreme weather event-related mortality in the contiguous United States. It also depicts the state-specific “Dollars Lost to Extreme Weather-Related Mortality” for the state in which a selected county is located.

How to use the dashboard

Choose an extreme weather event in the left panel to color the map by each county’s national percentile for that event’s excess mortality rate. Click a county on the map (or find it with the search box) to open its profile: national rankings for every event type, the “Excess Mortality Rate Ranking (National)” chart, and the “Dollars Lost to Extreme Weather-Related Mortality” trend for the county’s state. The full rankings dataset can be downloaded from the Data menu in the header (GeoJSON or CSV).

Monetary calculations

Dollars lost to extreme weather-related events were calculated using the U.S. Environmental Protection Agency’s Value of Statistical Life (VSL). Losses are calculated at the state level to protect potentially identifiable health information at the county level.

References

See the following publications for more information on the methods used to estimate the county-level extreme weather event mortality rates used for these rankings.

Wildfire Smoke PM_2.5
Ma, Y., Zang, E., Liu, Y., Wei, J., Lu, Y., Krumholz, H. M., Bell, M. L., & Chen, K. (2024). Long-term exposure to wildland fire smoke PM_2.5 and mortality in the contiguous United States. Proceedings of the National Academy of Sciences, 121(40), e2403960121. doi:10.1073/pnas.2403960121

Heat and Cold
Chu, L., Dubrow, R., & Chen, K. (2025). Heat- and Cold-Related Mortality Burden in the US From 2000 to 2020. JAMA Network Open, 8(11), e2542269. doi:10.1001/jamanetworkopen.2025.42269

Drought
Hu, Y., Chu, L., Wang, P., Abadi, A. M., Qiu, M., & Chen, K. (2025). Mortality Attributable to Drought, Wildfire Smoke, and Their Concurrent Added Effects in the Contiguous United States. medRxiv. doi:10.1101/2025.09.24.25336547

Flood
Chu, L., Warren, J. L., Spatz, E. S., Lowe, S., Lu, Y., Ma, X., Ross, J. S., Krumholz, H. M., & Chen, K. (2025). Floods and cause-specific mortality in the United States applying a triply robust approach. Nature Communications, 16(1), 2853. doi:10.1038/s41467-025-58236-0

Developers

XToll was developed by researchers at the Yale Center on Climate Change and Health (YCCCH) and in the Climate, Health, and Environment Nexus Lab (CHENLab).

• Kai Chen, PhD
• Lingzhi Chu, PhD
• Ying Hu, PhD
• Mitchell Manware, MPH

Last updated: 15 July 2026