Wildfires

Wildfires are increasing around the globe in frequency, severity and duration, heightening the need to understand the health effects of wildfire exposure. The risk of wildfires grows in extremely dry conditions, such as drought, heat waves and during high winds.

Wildfire smoke is a mixture of hazardous air pollutants, such PM_2.5, NO₂, ozone, aromatic hydrocarbons, or lead. In addition to contaminating the air with toxic pollutants, wildfires also simultaneously impact the climate by releasing large quantities of carbon dioxide and other greenhouse gases into the atmosphere. 

With climate change leading to warmer temperatures and drier conditions and the increasing urbanization of rural areas, the fire season is starting earlier and ending later. Wildfire events are getting more extreme in terms of acres burned, duration and intensity, and they can disrupt transportation, communications, water supply, and power and gas services. 

Wildfires that burn near populated areas can have significant impact on the environment, property, livestock and human mortality and morbidity depending on the size, speed and proximity to the fire, and whether the population has advanced warning to evacuate.

Wildfire smoke is a mixture of air pollutants of which particulate matter (PM) is the principal public health threat.

PM_2.5 from wildfire smoke is associated with premature deaths in the general population, and can cause and exacerbate diseases of the lungs, heart, brain/nervous system, skin, gut, kidney, eyes, nose and liver. It has also been shown to lead to cognitive impairment and memory loss. Firefighters and emergency response workers are also greatly impacted by injuries, burns and smoke inhalation, particularly at high concentrations.

More interdisciplinary research is warranted to understand the latent and long-term health effects of wildfire exposure on vulnerable populations (children, older people, pregnant people, chronically ill people), particularly for geographic areas enduring repeated and cyclical exposure to these wildfire events.

The magnitude of the physical and human costs from wildfires can be reduced if adequate emergency prevention, preparedness, response and recovery measures are implemented in a sustainable and timely manner. 

Working with Member States, WHO helps to build resilient and proactive health systems that can anticipate the needs and challenges during emergencies, so that we can be more likely to reduce risks and respond effectively when needed. 

WHO works with partners in preparing, preventing, detecting, responding and recovering from emergencies and disasters, including environmental exposures, such as

• implementing early warning systems and issuing health and air quality advisories;
• containing the release of hazardous materials;
• assessing health needs of the community and infrastructure damage;
• restoring primary care services, like immunization, child and maternal health, and mental health;
• strengthening human resources for disaster management;
• collecting, analysing and disseminating information related to emergencies and disasters that are likely to occur in a region;
• establishing and managing stocks of relief supplies and equipment;
• calling for emergency funding to support health action; and
• developing national policies, recommendations and national emergency response plans.