Los Angeles Wildfires: Air Quality Warning

As LA’s older burned homes and structures release toxic substances into the air, authorities have issued warnings about carcinogens like asbestos, silica, and benzene.

Wildfires—often fueled by dry vegetation, Santa Ana winds, and prolonged drought conditions—are a recurring and devastating phenomenon in California, with the recent Los Angeles fires drawing attention to just how devastating this issue can be. Now seemingly a natural part of the state’s ecosystem, they’ve become more frequent and severe in recent years primarily due to climate change and urban expansion. 

The consequences of fire destruction are far-reaching, from property damage and the displacement of residents to significant health hazards caused by polluted air. Even injuries and deaths have been reported.

Los Angeles, with its mix of urban sprawl and natural landscapes, is particularly vulnerable to damaging fires. Many homes and buildings in the city date back to the mid-20th century, constructed before strict building codes addressing fire resistance and hazardous materials were in place. This historical context contributes to the presence of dangerous substances released during wildfires, particularly when older structures are destroyed, including asbestos, lead and others.

While the negative impact of these fires is vast, this article will focus specifically on the air quality concerns that follow.

Currently, Southern California is undergoing significant wildfire issues, particularly the Palisades and Eaton fires, which, as of mid-January 2025, have claimed more than two dozen lives, destroyed over 12,000 structures, and burned more than 60 square miles of this well-developed landscape. Officials have issued mandatory evacuation orders for 88,000 residents in Los Angeles County, with an additional 84,800 under evacuation warnings due to potential dangers, and twelve-hour curfews are in effect in affected zones, from 6 p.m. to 6 a.m.

The exact causes of the fires remain unclear, with speculation that both environmental conditions and arson could be to blame. Many suspect they’ve been brought on by the powerful winds and dry conditions that California has long experienced. The region has also been suffering from a substantial dry spell, having had no rainfall for more than 250 consecutive days.

To date, however, law enforcement has made more than 50 arrests related to the fires, including three for suspected arson. These incidents involve an individual using a barbecue lighter and other conductors to ignite bushes and trash cans. Additional arrests have also been made for curfew violations, drone activity, burglary, and unauthorized access to restricted areas.

As a result of the fires, an air quality warning has been issued. Damaged buildings and other infrastructure have caused toxins to be released into the air, with older buildings of particular concern as they are more likely to be contaminated with lead and asbestos.

Unsafe drinking water has also emerged as a very real and present issue. In Pasadena, damaged water infrastructure, including burned pumps and storage tanks, prompted a “Do Not Drink” advisory for a third of the area’s customers. Although this notice has since been lifted following testing, experts are still worried that hazardous chemicals and particulates will enter the supply.

Air Quality Warning

The smoke caused by the fires can contain a variety of toxins, including carbon monoxide, chemicals, lead, asbestos, and more. Exposure to these pollutants can lead to severe respiratory and cardiovascular issues, particularly in vulnerable populations such as children, the elderly, and individuals with pre-existing health conditions. Recent reports, including advisories from the California Department of Industrial Relations, emphasize the need for residents to stay informed and take protective measures during wildfire events.

Hazardous Pollutants from Burning Buildings

When fires engulf buildings, the air becomes contaminated with substances released from construction materials. Older buildings, particularly those erected before the 1970s, often contain materials now recognized as toxic. While these materials have long since been replaced with safer alternatives, any time an ageing structure burns, is damaged by a natural disaster, or even experiences routine wear and tear, there is a risk of pollutants being released and breathed in by those nearby.

This issue was a prominent one during the destruction of the World Trade Center in 2001, for example, which has had lingering effects on first responders and victims who were at Ground Zero on that tragic day. In the years that have followed, it has become apparent that the damage has resulted in long-lasting health effects for many. Let’s take a closer look.

Air Quality Case Study: The World Trade Center

When the towers collapsed at the World Trade Center on September 11, 2001, an extensive cloud of toxic debris covered lower Manhattan, New York. The damage caused during the infamous terrorist attacks sent a mixture of concrete, glass fibers, heavy metals, and asbestos fibers into the air, leaving first responders, survivors, and nearby residents exposed to carcinogenic particulates and vulnerable to health complications as a result. Despite originally declaring that the air was safe to breathe in, health officials and health researchers have since realized that this wasn’t the case.

According to the Centers for Disease Control and Prevention (CDC), over 400,000 individuals were exposed to harmful substances not only on the day of the attacks but well into the months that followed, including asbestos, silica, and benzene, to name a few. As of recent reports, more than 71,000 individuals are enrolled in the World Trade Center Health Program, which tracks health complications related to the attack. Approximately 68% of these enrollees have been diagnosed with at least one chronic condition, including respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD), mental health conditions like post-traumatic stress disorder (PTSD), and cancers linked to toxic exposures, including lung cancer and mesothelioma. Lung function impairments have also been documented in 42% of first responders, and rates of certain cancers, such as thyroid and prostate cancer, are significantly higher among those exposed than the general population.

These health effects draw attention to future issues that Los Angeles residents and responders could face.

The LA Fire: Primary Pollutants Concerns

Five major pollutants commonly found in fire smoke originating from buildings include the following:

1. Asbestos

Asbestos, a naturally occurring mineral, was widely incorporated into building materials for decades due to its exceptional durability, fire resistance, and insulating properties. It was commonly used in applications such as wall and attic insulation, roofing shingles, floor tiles, and pipe insulation. When a building containing asbestos catches fire, the intense heat and structural damage can release microscopic asbestos fibers into the air, and ironically, the very thing that made asbestos so favorable at one time also makes it more likely that harmful fibers will be inhaled. Indestructible even in extreme heat, these fibers, when inhaled, can lodge in the lungs, leading to serious long-term health conditions such as asbestosis, lung cancer, and mesothelioma.

Because asbestos was so prevalent during the 20th century, many structures contain it, particularly in and around Los Angeles where rapid urban development and industrial growth in years led to widespread use of asbestos-containing materials (ACMs) in residential, commercial, and industrial buildings.

2. Lead

Lead has historically been a common component of building materials, particularly in paints, plumbing systems, and various construction products, due to its durability and resistance to corrosion. Until the late 1970s, lead-based paint was widely used to coat walls, doors, and window frames, as it provided a smooth finish and could withstand wear and tear. Lead pipes and solder were also prevalent in plumbing systems, making lead a critical part of many structures built during the 20th century. However, as the health risks of lead exposure became more apparent, its use in construction materials declined, and stricter regulations were implemented to limit its presence in new buildings.

The hazards of lead exposure become particularly severe when lead-containing materials are subjected to fire. During combustion, lead particles and fumes are released into the air, creating a significant inhalation risk for those in or near the affected area. These airborne particles can settle on surfaces and taint the surrounding environment, leading to long-term risks through ingestion or skin contact. The health consequences of lead exposure include neurological damage, particularly in children, leading to developmental delays, learning disabilities, and cognitive impairments. Adults exposed to lead may experience cardiovascular problems such as increased blood pressure and hypertension, as well as kidney damage. Even short-term exposure to lead can be dangerous, especially for vulnerable populations like pregnant women and young children, as it can result in serious health complications, including harm to fetal development.

3. Polychlorinated Biphenyls (PCBs)

Polychlorinated biphenyls (PCBs) are synthetic chemicals that were extensively used in buildings constructed before their ban in 1979. Known for their stability and insulating properties, PCBs were a common component in electrical equipment such as transformers and capacitors. Additionally, they were incorporated into building materials like caulks, paints, and sealants to enhance durability and flexibility. Despite the prohibition of PCBs in new construction, older buildings may still harbor these substances, posing risks during renovations, demolitions, or fires.

When materials containing PCBs burn, they release dioxins and furans, which are among the most toxic environmental pollutants. Exposure to these compounds can have severe health consequences. Classified as probable human carcinogens, long-term exposure to PCBs has been linked to increased risks of certain cancers. They can also suppress the immune system, diminishing the body’s ability to fight infections, and disrupt the endocrine system, leading to hormonal imbalances and reproductive health issues. PCBs persist in the environment, meaning their toxic effects can continue long after the initial fire, contaminating soil, water, and air for a long time to come.

4. Formaldehyde in Buildings and Its Health Hazards

Formaldehyde, a widely used chemical in construction, has been a staple in the production of pressed wood products, insulation, adhesives, and other building materials due to its cost-effectiveness and strong bonding properties. Many materials designed to improve structural integrity and insulation efficiency contain formaldehyde. While its use has declined with growing awareness of its health impacts, the chemical remains a concern in older structures and some modern materials, particularly when fires break out.

When materials containing formaldehyde are exposed to fire, the compound is released into the air as a volatile organic compound (VOC). Inhalation or dermal exposure to formaldehyde can cause respiratory irritation, such as coughing, wheezing, and shortness of breath, as well as skin and eye discomfort. Extended exposure has been associated with more severe outcomes, including an elevated risk of nasopharyngeal cancer and leukemia. In enclosed or poorly ventilated spaces, the risks are even greater, with levels of formaldehyde accumulate to dangerous levels during or after a fire.

5. Synthetic Materials and Plastics in Buildings and Their Health Hazards

The widespread use of synthetic materials and plastics in modern construction has revolutionized building design and functionality. These materials are commonly found in insulation, flooring, furniture, and fixtures due to their versatility, durability, and cost-effectiveness.

When synthetic materials and plastics burn, they release a range of toxic gases that can lead to both immediate and long-term health risks. Among these are hydrogen cyanide, a highly poisonous compound that interferes with cell oxygen use; carbon monoxide, a lethal gas that prevents oxygen transport in the blood; and dioxins and furans, potent carcinogens linked to various cancers. Acute exposure to these gases can cause respiratory distress, neurological damage, and even death. Cancers and cardiovascular diseases have also followed exposure.

Specifics of California’s Air Quality Warnings

Southern California health officials are cautioning that substances such as lead, arsenic, and asbestos are likely being released into the air even though the Air Quality Index (AQI) typically does not measure the quantities present. This means that even if the AQI shows good conditions, invisible particulate matter could still pose health risks—reminiscent of the situation present during the World Trade Center attacks. This issue is not only true in fire damaged areas but adjacent ones as well. Residents have been advised to wear masks and limit their time spent outdoors.

For those returning to fire-damaged homes, health officials have also recommended wearing gloves and tightly fitted N-95 masks to avoid exposure. Loose-fitting or fabric masks do not offer adequate protection. They are warning, too, that the cleanup process in the affected areas may further expose individuals to toxins, particularly if proper safeguards aren’t put into place.

Protecting Yourself from Airborne Hazards

In addition to keeping current on the status of the air quality within the vicinity of the fires, wearing N95 masks and limiting outdoor activities, there are a few other ways residents can remain safe. Individuals are encouraged to monitor air quality through reliable sources like AQI apps or websites providing timely updates about outdoor conditions, albeit the data here is limited (as specified above). When AQI levels are high, staying indoors can limit exposure to toxins.

Indoors, using HEPA filters in HVAC systems or portable air purifiers can help maintain air quality, while sealing windows, doors, and gaps prevents contaminated air from entering. Property owners impacted by fire debris should follow proper clean-up measures, wetting the rumble to reduce dust while removing it. It’s also important to dispose of any waste following protocols put into place by regulators to minimize exposure risks.

Moving Forward

The Los Angeles fires are not only devastating due to widespread damage they’ve caused, but from a public health perspective as well. The destruction of older buildings releases hazardous pollutants, including asbestos, lead, PCBs, formaldehyde, and toxic substances from plastics, each with serious health implications.

By understanding the risks associated with wildfire pollution and taking proactive measures, residents can minimize exposure and safeguard against long-term complications. As the frequency of wildfires continues to rise, in general, awareness and preparedness remain key to reducing their impact on communities and the environment. Putting protocols and equipment into place ahead of time can help residents more readily access the resources they need should these fires continue.