The Los Angeles wildfires of early January 2025 marked a watershed moment for America’s urban disaster preparedness. In just a few days, wind-driven fires claimed 29 lives, destroyed more than 16,000 structures, and exposed millions to toxic smoke. The lessons learned from this disaster are detailed in a Nature Cities commentary authored by Dr. Amir AghaKouchak, Dr. Joseph Allen and his Healthy Buildings team, and colleagues from leading institutions. Their analysis compels city leaders, policymakers, and residents to rethink fire risk—not just as a climate or environmental threat, but as a pressing challenge to public health and even national security.
Three Key Takeaways
- Urban fire risk is rising: Large, wind-driven fires in cities can be extremely destructive, threatening both public health and security.
- Air pollution and indoor health matter: Wildfire smoke and chemicals travel long distances and can make indoor air harmful, so reducing exposure is a top priority.
- Smart policies can help: Planning evacuations, managing vegetation, and upgrading infrastructure are essential to limit the damage from future urban fires.
Facing Urban Wildfire Reality
Wildfires are no longer just a problem for remote forests. The 2018 Camp Fire, the 2023 Maui wildfires, and most recently, the 2025 Los Angeles fires have shown that cities—with their dense buildings, busy streets, and modern materials—are now squarely in the danger zone. Fast-spreading flames can devastate neighborhoods, strain emergency response, and leave millions at risk from both fires and their aftereffects.
What makes city fires especially dangerous is how they are connected to many other risks: from interrupted power and transportation to long-lasting health threats from poor air quality. As our cities grow and the climate changes, understanding these overlapping challenges is the first step toward real resilience.
Key Challenges for Building Urban Fire Resilience
As wildfires increasingly threaten cities, leaders must address several interconnected challenges to keep people and infrastructure safe. Four crucial areas require focused attention:
- National Security Risks: Urban fires can disrupt entire cities or even national infrastructure. They pose security risks because critical systems—like power, communication, and transportation—are vulnerable to both natural fires and intentional attacks.
- Smarter Land Management: Managing grass, trees, and brush in and around cities helps slow fire spread and lowers risk. Controlled burns or trimming vegetation, especially after wet years, can make a major difference in preventing large-scale disasters.
- Advance Evacuation Planning: Cities need detailed evacuation plans before fires start. These should account for traffic, local population needs, and fast communication so everyone knows what to do if a fire threatens.
- Stronger Infrastructure and Building Codes: Upgrading buildings with fire-resistant materials and improving essential services—like gas and power lines—help cities withstand and recover from fires more quickly. Updated codes and infrastructure reviews are key to long-term resilience.
Air Quality Hazards and Indoor Health
One of the most far-reaching and ongoing threats from urban fires is air pollution. In this commentary, the Healthy Buildings team highlighted how wildfire smoke sends fine particles and harmful chemicals into the air, sometimes over long distances. These pollutants get into buildings and linger, turning indoor spaces into health hazards—an urgent issue as people spend about 90% of their time indoors.
Elevated heavy metal and black carbon concentrations in Huntington Park, Los Angeles, during the Los Angeles fires. Values are in μg m−3 (black carbon) or ng m−3 (metals). Data are publicly available from the South Coast Air Quality Management District (AQMD)
During the 2025 LA fires, monitoring in neighborhoods like Huntington Park showed a sharp rise in heavy metals and other pollutants linked to breathing problems and other illnesses. The risks do not go away when the fire is out. Winds can stir up ash for weeks, and cleanup or rebuilding can spread harmful dust. People living in partially burned or poorly cleaned buildings can keep being exposed to these dangerous particles.
Reducing these health risks means acting on several fronts:
- Using portable air cleaners with HEPA and carbon filters to trap particles and gases.
- Changing air filters in HVAC systems and air cleaners after any nearby fire event.
- Relying on indoor air quality monitors that alert people to changes and let them know when it’s safe to open windows.
- Providing clear information to the public about how to protect themselves—like keeping windows shut when outdoor smoke is bad.
- Limiting hazardous materials in home products and construction, replacing them with safer options that are less toxic if burned.
These steps, recommended by the Healthy Buildings team, are crucial for protecting families, especially in dense urban settings
LA Fire HEALTH Study
In response to the 2025 LA Fires, a unique research partnership called the Los Angeles Fire Human Exposure and Long-Term Health Study (LA Fire HEALTH) has been launched, supported by the Spiegel Family Fund. This 10-year effort brings together experts from Cedars-Sinai, Harvard, UCLA, UC Irvine, Yale, Stanford, and several other top institutions. The goal is to track which pollutants are present after urban fires, where they go, how long they last, and what health impacts they cause. Part of this research—as well as other important wildfire and health studies—has been supported by the LA Fire Health Study, helping to protect Los Angeles and inspire cities everywhere to address these dangers.
Toward a Safer Future
Wildfires are now an urban reality, but disaster isn’t inevitable. By recognizing these new risks and acting on practical solutions—from smarter land management and stronger building codes to effective evacuation plans and national security awareness—cities can protect both lives and livelihoods. Preparing today means we’ll be ready for tomorrow’s challenges, turning hard lessons into lasting safety.
Read the full study here: https://www.nature.com/articles/s44284-025-00296-w