Fires, smoke and health

Smoke and ash contain substances that are harmful to health.

Smoke can make it hard for some people to breathe. Inhaling smoke may cause coughing, shortness of breath and throat irritation. Smoke can irritate the eyes, causing a stinging sensation.

If you are in an area where you can see or smell smoke or have received an emergency alert, you should:

• follow the advice of emergency services and leave the area if this is required
• if you are safe to stay in the area, remain indoors and shut your windows and doors
• turn off your air conditioning or switch to ‘recirculate’
• keep pets inside with clean water and food and keep pets' bedding inside if possible
• disconnect your downpipe if it connects to a water tank – this is important if there is a risk of water contamination from airborne ash, debris or fire retardants from firefighting.
• seal up windows and doors with blankets and towels
• avoid frying and indoor combustion like candles and wood burners
• reduce outdoor exercise.

Smoke inhalation can be particularly dangerous for certain groups, including:

• elderly or pregnant people
• young children
• those with medical conditions such as asthma or heart disease.

Keep respiratory medication within easy reach.

In healthy people, most symptoms disappear soon after their exposure to smoke stops. Usually, exposure does not cause long-term health problems.

If you did not experience any symptoms at the time you were exposed to the smoke, you are unlikely to have any long-term health effects.

Health risks from ash and smoke - HealthEdexternal link  

Fires can expose people to a range of hazardous substances. In fact, every major fire is a chemical incident. The size and scale of fire events vary greatly, and the consequences of these releases are also variable. The longer a fire burns, the more products of combustion are formed.

Fires can pose a substantial threat because:

• They release chemicals into the air that may disperse at concentrations well above background levels
• New chemicals can be formed as a result of combustion
• The dispersion of fire-fighting water can cause material from the fire to enter waterways
• The density of people increases in an urban environment.

There may also be intense local deposition of material from the fire, including parts of the structure of the impacted buildings.

In cases of fires in the urban and built environment, public health officers in the National Public Health Service within Health New Zealand | Te Whatu Ora (NPHS) may be involved if there are risks to public health.

The NPHS may be asked for advice on environmental sampling during and after fires, as well as advice on other health-related matters such as evacuation and sheltering. This advice is incident-specific because the combustion products produced will vary depending on the chemicals and materials present and the temperature of the fire, as well as the numbers and vulnerabilities of people who may be exposed (for example, children, older people).

Wildfires produce a large amount of smoke that disperses widely and can affect populations far from the fire source. They can expose people to a range of hazardous substances. In fact, every major fire is a chemical incident. The longer a fire burns, the more products of combustion are formed. The effect of these products on water quality is influenced by, among other things, the fire’s intensity, severity and duration. Changes in the quality of surface waters are greatest immediately after the fire.

In addition to the obvious risks from burning, wildfires can pose a substantial threat because they release smoke, gases and ash into the air that may be hazardous downwind, through inhalation or being deposited in roof or surface water catchments. Further, the dispersion of firefighting water can cause material from the fire and firefighting chemicals to enter waterways. In some instances, hazardous materials (such as asbestos in roofs and agrichemicals stored in barns and rural industrial sites) may be in the pathway of the wildfire and may contaminate land, air or water.

The NPHS is involved in wildfire responses if the fires put public health at risk. For example, people may ask public health officers for advice on health-related matters such as evacuation and sheltering (that is, staying at home if the conditions are safe to do so), as well as temporary cessation of outdoor public activities (such as concerts or sports).

Make sure you burn waste in a way that keeps people safe. Waste, especially after a natural disaster, may contain toxic chemicals that cause long-term health problems such as heart disease and cancer.

Any fire, but particularly an open-space burn-off, is unpredictable. Changes to wind speed and direction are particular dangers to be aware of and plan for. It is important to avoid smoke drifting over residential areas and homes.

To reduce the risk to yourself and your community make sure you follow the advice from Fire and Emergency New Zealand on clearing debris with a burn pile.

Safety tips for burn piles — Fire and Emergency New Zealandexternal link

Seek specialist advice from an occupational hygienist if you are burning a pile with high concentrations of mixed waste.

Find and adviser — Health and Safety Association NZexternal link