Pedestrian Suffers Burns During Record Heat Dome
Extreme heat events are increasingly endangering human health in myriad ways. A recent case study published in the New England Journal of Medicine highlights one such incident in which a 56‑year‑old man, impaired by alcohol, sustained second‑degree burns on the soles of his feet after walking barefoot across asphalt during the unprecedented 2021 Pacific Northwest heat dome. This episode underscores the convergence of climate change, urban surface physics, and public health vulnerabilities.
Case Report and Clinical Management
- Patient Presentation: A 56‑year‑old male arrived at a regional burn center with red, oozing wounds on both soles and the left heel. The right heel exhibited tense blisters, and several toes showed mixed‑depth burns.
- Environmental Conditions: Ambient air temperatures peaked at 42 °C (108 °F), approximately 21 °C above the region’s 30‑year average. Infrared thermography studies indicate that asphalt can reach 40–60 °F (22–33 °C) above ambient on clear summer days due to high solar absorptance (~0.95).
- Treatment Protocol: Wound care followed Advanced Burn Life Support (ABLS) guidelines. The patient received systemic analgesia (IV opioids), enzymatic debridement, topical silver sulfadiazine, and an antimicrobial foam dressing to maintain a moist healing environment. At 4‑week follow‑up, re‑epithelialization was observed without hypertrophic scarring.
Thermodynamic Properties of Urban Surfaces
Asphaltic pavements consist of bitumen binder (viscosity ~500–1 000 cSt at 60 °C) and mineral aggregates. Their dark color and low albedo (<0.05) cause solar energy absorption per unit area to exceed 900 W/m2 on sunny days. Stefan–Boltzmann emissivity (ε≈0.95) drives longwave radiation, but convective heat flux remains insufficient to prevent surface temperatures from climbing above 70 °C. The urban heat island (UHI) effect exacerbates these peaks, with nighttime surface temperatures staying 5–10 °C above peri‑urban levels.
Innovations in Pavement Technology
To mitigate surface overheating, municipalities are trialing cool pavements: high‑albedo coatings, reflective aggregates, and polymer‑modified asphalts embedded with phase‑change materials (PCMs). Recent laboratory tests by the National Renewable Energy Laboratory (NREL) show that microencapsulated paraffin PCMs in a surface course can reduce peak temperatures by 8–12 °C. In Los Angeles, a pilot project applying reflective sealants on 2 km of roadway cut pavement temperatures by an average of 10 °C during the summer of 2024.
Public Health Implications and Policy Recommendations
- Vulnerable Populations: Unhoused individuals, children, the elderly, and those under the influence of substances face elevated risk of contact burns during heat waves.
- Early Warning Systems: Integrating land surface temperature data from satellites (e.g., NASA’s ECOSTRESS) with municipal alert platforms can enable real‑time notifications for high‑risk areas.
- Regulatory Standards: Adopting American Society for Testing and Materials (ASTM) albedo requirements for new pavements and mandating shaded rest areas in urban design can reduce heat exposure.
Future Outlook
Climate models from the Intergovernmental Panel on Climate Change (IPCC AR6) project a doubling of extreme heat days in many mid‑latitude cities by 2050. Without aggressive greenhouse gas mitigation and urban adaptation measures, contact burn incidents like this one will become more frequent and severe. Cross‑disciplinary collaboration between climatologists, material scientists, urban planners, and health professionals is essential to develop resilient, safe urban environments.