If our volunteer firefighters are concerned about smoke exposure, we owe it to them to better understand the problem and provide some reasonably practicable solutions.
Bushfire smoke contains:
- Carbon Monoxide (CO)
- Methane (CH₄)
- Fine particulate matter
- Volatile organic compounds
- Oxides of Nitrogen
- And many other compounds (depending upon fuel types)
Workplace exposure standards for airborne contaminants
The workplace exposure standards for airborne contaminants are readily available from Safe Work Australia and can be downloaded below.
This document contains the list of workplace exposure standards (WES) and guidance on their application. Compliance with the WES is required under jurisdictional Work Health and Safety (WHS) laws.
Carbon Monoxide (CO)
Carbon monoxide is an odourless gas produced as a result of incomplete combustion processes. Exposure to CO results in a deficiency of oxygen reaching the body, causing tissue damage to a range of organs including the brain and heart. At extremely high levels, CO can cause death (carbon monoxide poisoning).
Exposure to CO occurs through inhalation. CO is carried through the body in the blood. CO is taken up in the blood more easily than oxygen, it reduces the amount of oxygen available in the blood stream.
Health effects of CO
The presence of symptoms from CO exposure is related to the length and extent of exposure, in addition to the health and overall condition of the firefighter exposed. The most affected organs are those that use the highest levels of oxygen, such as the brain and heart.
The most commonly reported symptoms of acute (short term) exposure to high levels of carbon monoxide include:
- headaches, dizziness, nausea
- metallic taste
- darkened vision
- muscular weakness, in-coordination and impaired judgement
- numbed reflexes and reaction times
- sleepiness, collapse and unconsciousness
- increased pulse and breathing
- heart attack
Prolonged exposures of CO can result in impaired judgement and reflexes, firefighters conducting activities while experiencing carbon monoxide exposure symptoms may be at higher risk of other fireground hazards.
Acute exposures to high levels of carbon monoxide may result in death, even after a single exposure. Cause of death is through oxygen depletion to vital organs. Underlying medical conditions may increase the chances of serious illness or injury from carbon monoxide exposure.
Delayed neurological effects may also be seen days to months after exposure, characterised by personality and behavioural changes, dementia, depression and muscular shakes. The majority of delayed neurological symptoms normally go away within a year of onset.
Ongoing chronic exposure to high levels of carbon monoxide may result in:
- recurring headaches
- foetal changes in pregnant women (including miscarriage)
- personality changes
- decreased exercise tolerance
- impaired judgement.
Carbon Monoxide (CO) concentrations exceeding 300 parts per million (ppm) are common around bushfires.
The Time Weighted Average (TWA) of CO is 30ppm.
TWA means the maximum average airborne concentration of a substance when calculated over an eight hour working day, for a five day working week.
Class P3 particulate filters
Class P3 particulate filters can be added for protection against some highly toxic or highly irritant particulates (when worn with a full face respirator).
Read More: Improved Respiratory Protection for Firefighters – Part 3: What can we do about Carbon Monoxide?
This video is being shared for the science buffs: