Fire Smoke.

Fire smoke

The composition of them Gaseous mixture "fire smoke" varies according to the fuel and conditions. A well-oxygenated, outdoor wood fire nay produce a very light smoke with relatively few chemicals. Although there are particulates in wood smoke capable of causing low-level inflammation, this type of exposure rarely requires medical attention. Toxic fire smoke, however, is the result of a fire when the fuel load is more complex (e.g plastics, artificial facbrics) or the oxygen supply us limited. Structure fires are usually the primary concern when we consider smoke inhalation, but toxic fire smoke is also created at trash bin/dumpster and automobile fires. Wildfire smoke can also be toxic if the burning area was recently sprayed with chemicals. 

Chemicals are released from incomplete combustion and from the off-gassing of glues used in the manufacturing process. 

Also contained within fire smoke are small Inhalable particles known as fines and ultrafine. These particles (less than 0.00001 mm in diameter) are less well-known to the public safety services but can be very damaging to health. Ultrafine particle concentration can be very high after fire suppression, even when there doesn't appear to be a significant amount of smoke in the room. 

Acute vs Chronic Effects:-

Smoke exposure can injure the victim immediately (acute) or over a longer period of time (chronic/delayed). Victims trapped near the fire source may be exposed to hot and dense smoke with off-gassing chemicals including carbon monoxide (CO) and cyanide. 

Often, these chemicals cause bronchospasm, sloughing of the epithelial lining of the airway, mucus secretion, and inflammation and surfactant inactivation. How quickly these symptoms manifest depends on the chemicals within the smoke and the intensity and duration of the exposure. Smoke inhalation care and transport to the nearest appropriate hospital. 

In contrast, fire fighters working at the scene after the fire has been extinguished can be exposed to lower levels of these same chemicals and particulates. Some fire fighters may leave the scene with elevated but subclinical doses of CO or hydrogen cyanide (HCN). The cumulative exposure to chemicals and particulates over years of service can result in respiratory conditions, heart disease or cancer. The exact particulate exposure required to cause health issues cause cardiac toxicity. Tollbooth workers and boilermakers are routinely exposed to ultrafine particles and suffer worse forms of cardiac disease and arrythmia when compared to other occupations. 

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Carbon Monoxide and hydrogen Cyanide:-

CO and HCN are both chemical ashyxiates commonly found in fire smoke, and exposure should be considered in every case of smoke inhalation. CO is produced when a carbon-containing material, such as wood, is burned and there isn't enough oxygen present to completely transform into carbon dioxide (CO2). It's also commonly found near burning hydrocarbon fuels (e.g., gasoline and diesel). Although the fire smoke or fuel fumes are easy to identify, CO itself is colourless, odourless, tasteless and initially non-irritating. Hemoglobin has a high affinity for CO and once bound, the new molecule (carboxyhemoglobin [COHh] is no longer capable of binding oxygen. Since oxygen dissolves poorly in blood plasma, high COHb levels result in poor oxygen-carrying capacity and hypoxemia. 

HCN is a by-product of the combustion of materials such as green wood, tobacco, cotton, paper, wool and silk. When burned, these materials release nitrogen gas into the air. Hot fires in enclosed spaces can convert the nitrogen gas to small amounts of cyanide. Unlike CO that alters the blood capacity to transport oxygen, cyanide affects the cell and accumulates lactic acid and the intracellular pH drops. 

You should assume that both CO and HCN are present in fire smoke and that fire victims that been poisoned by both, resulting in both oxygen transport and utilization issues. The immediate danger to life and health toxicity for cyanide is much lower (50ppm) when compared to CO (1200ppm), so firefighters should be extremely cautious about working in a smoky environment unless wearing self-contained breathing apparatus (SCBA). 

Five major pollutants

EPA establishes an AQI for five major air pollutants regulated by the Clean Air Act. Each of these pollutants has a national air quality standard set by EPA to protect public health:

• ground-level ozone
• particle pollution (also known as particulate matter, including PM2.5 and PM10)
• carbon monoxide
• sulfur dioxide
• nitrogen dioxide

Who is at greatest risk from wildfire smoke?

• People who have heart or lung diseases, like heart disease, lung disease, or asthma, are comparatively at higher risk from wildfire smoke.
• Older adults are more likely to be affected by smoke. This may be due to their increased risk of heart and lung diseases.
• Children are more likely to be affected by health threats from smoke. Children’s airways are still developing and they breathe more air per pound of body weight than adults. Also, children often spend more time outdoors engaged in activity and play.

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#Take steps to decrease your risk from wildfire smoke

*Be prepared for wildfires

*Check local air quality reports. Listen and watch for news or health warnings about smoke. Find out if your community provides reports about the U.S. Environmental Protection Agency’s Air Quality Index (AQI) or check the report on In addition, pay attention to public health messages about safety measures.

*Consult local visibility guides. Some communities have monitors that measure the amount of particles in the air. In the western United States, some states and communities have guidelines to help people determine if there are high levels of particulates in the air by how far they can see.

*Keep indoor air as clean as possible if you are advised to stay indoors. Keep windows and doors closed. Run an air conditioner, but keep the fresh-air intake closed and the filter clean to prevent outdoor smoke from getting inside. If you do not have an air conditioner and it is too warm to stay inside with the windows closed, go to a designated shelter away from the affected area.

*Avoid activities that increase indoor pollution. Burning candles, fireplaces, or gas stoves can increase indoor pollution. Vacuuming stirs up particles already inside your home, contributing to indoor pollution. Smoking also puts even more pollution into the air.

*Prevent wildfires from starting. Prepare, build, maintain, and extinguish campfires safely. Follow local regulations if you burn trash or debris. Check with your local fire department to be sure the weather is safe enough for burning.

*Follow the advice of your doctor or other healthcare provider about medicines and about your respiratory management plan if you have asthma or another lung disease. Consider evacuating if you are having trouble breathing. Call your doctor for advice if your symptoms worsen.

*Do not rely on dust masks for protection. Paper “comfort” or “dust” masks commonly found at hardware stores are designed to trap large particles, such as sawdust. These masks will not protect your lungs from the small particles found in wildfire smoke.

*Evacuate from the path of wildfires. Listen to the news to learn about current evacuation orders. Follow the instructions of local officials about when and where to evacuate. Take only essential items with you. Follow designated evacuation routes–others may be blocked–and plan for heavy traffic.

*Protect yourself cleaning up after a fire. Cleanup work can expose you to ash and other products of the fire that may irritate your eyes, nose, or skin and cause coughing and other health effects.