Beyond fatalities, wildfires and the resulting smoke and ashes can cause:

• burns and injuries;
• eye, nose, throat and lung irritation;
• decreased lung function, including coughing and wheezing;
• pulmonary inflammation, bronchitis,
• exacerbations of asthma, and other lung diseases;
• exacerbation of cardiovascular diseases, such as heart failure;
• impacts to mental health and psychosocial well-being.
• Wildfires also release significant amounts of mercury into the air, which can lead to impairment of speech, hearing and walking, muscle weakness and vision problems for people of all ages. ^{4 4}WHO: WildfiresX

Wildfires occur in all vegetation zones across the world, but occur most often where droughts and heat waves occur. Fires can spread rapidly, covering extensive areas and inflicting severe damage to homes and the environment. 

Wildfire smoke can travel far distances and affect areas that are not directly exposed to the fire event, and may affect large numbers of people for days to months.^{5 5}Health impacts of wildfires. Finlay et al. 2012X The regions most affected by deaths related to wildfire smoke include sub-Saharan Africa, South America and Southeast Asia. ^{6 6}Estimated global mortality attributable to smoke from landscape fires. Johnston et al. 2012X

Extratropical regions, including the Pan-Arctic, have also experienced an increased number of fires in the last two decades. ^{7 7}Estimates of temporal-spatial variability of wildfire danger across the Pan-Arctic and extra-tropics. Justino et al 2021X

DIRECT IMPACTS

Those unable to escape the path of a wildfire may suffer burns, injuries or death, but wildfires primarily impact health through exposure to smoke. Health impacts increase in step with incremental increases in air pollution, and are seen especially in children, the elderly, and those with existing chronic medical conditions. 

Wildfire smoke is a mixture of air pollutants, of which particulate matter is the main health threat. These very fine particles can go deep into the lungs and, by themselves or in combination with other air pollutants, can exacerbate pre-existing diseases of the heart and lungs. 

Smoke can produce large amounts of carbon monoxide, carbon dioxide, nitrogen oxides, ozone and particulate matter, both coarse and fine (PM10 and PM2.5). It is these substances that negatively impact human health, and these health impacts are often long-term.

Even modest rises in pollution levels can cause major health impacts in a population if enough people are exposed or the smoke persists for a long time. 

INDIRECT IMPACTS

The indirect impacts of fires also affect health through the destruction of livelihoods and property as well as population displacement, which can negatively impact mental health and the provision of healthcare services. Forest fire smoke and fire retardant dropped by planes and helicopters can also pollute domestic water tanks and waterways with ash and particulates.

• Infants, young children, pregnant women and older adults are more susceptible to health impacts from smoke and ash.
• Smoke and ash from wildfires can greatly impact those with pre-existing respiratory diseases or heart disease, such as those suffering from asthma, chronic obstructive pulmonary disease (COPD) or cardiovascular disease.
• Firefighters and emergency response workers are also greatly impacted by injuries, burns and smoke inhalation.

The size and frequency of wildfires are growing due to climate change. Hotter and drier conditions are drying out ecosystems and increasing the risk of wildfires. The risk of wildfires increases in extremely dry conditions, such as during droughts and periods of high winds.

As a result of bigger, more frequent, and longer-lasting fires, larger populations, including urban populations far from the fire sites, are being exposed to harmful and prolonged levels of wildfire smoke. ^{8 8}The Limits of Livability – The emerging threat of smoke impacts on health from forest fires and climate change. GCHA, 2021X

Wildfires also simultaneously impact weather and the climate by releasing large quantities of carbon dioxide, carbon monoxide and fine particulate matter into the atmosphere. ^{9 9}WHO: WildfiresX

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.

Long term interventions:

• putting in place early warning systems and issuing health and air quality advisories;
• proposing fire danger maps to anticipate most vulnerable regions to fire occurrence;
• developing national policies, recommendations and national emergency response plans;
  strengthening human resources for disaster management;
• establishing and managing stocks of relief supplies and equipment;
• collecting, analyzing and disseminating information related to emergencies and disasters that are likely to occur in the region.

Emergency actions:

• 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;
• calling for emergency funding to support health action.