Information response

                                                                                                        bushfire Smoke research
    The composition and quantity of smoke             burning during the dry season in northern
    produced during a fire will differ depending      Australia caused an increase in hospital visits   Other CRC projects are researching aspects of
    on the chemistry and condition of the             for asthma (1) but the same effects were not      bushfire smoke.
    fuel, the amount and arrangement of fuel          found in a study undertaken after a large
                                                                                                        Behaviour of smoke plumes and hazes
    layers and the behaviour of the fire and          bushfire event in New South Wales (2).
                                                                                                        from rural or urban fires
    weather conditions. Many of the gaseous
                                                      Another study did not find any reduction          (Project B 2.1)
    aerosols produced in smoke can exist in
                                                      in lung function in symptomatic asthmatic
    the atmosphere for variable lengths of time                                                         This project is enhancing models of smoke
                                                      children during the same fires in New South
    ranging from days to months and can travel                                                          movement and integrating them with other
                                                      Wales (3).
    considerable distances.                                                                             meteorological tools, including the Smoke
                                                      A recent study conducted in Brisbane              Dispersion Forecasting Service, which is
    Particulate matter is not as long lived as
                                                      has shown that daily respiratory hospital         available through the Bureau of Meteorology.
    gaseous products and generally only remain
                                                      admission rates consistently increased with
    in the atmosphere for periods of hours                                                              Air Toxics Exposure and measurement
                                                      increasing levels of PM10 for both bushfire
    to weeks, depending on their size. Most                                                             (Project D 2.2)
                                                      and non-bushfire periods over a three year
    particulate matter emitted by combustion of
                                                      period. The findings were also suggestive         This project is advancing the knowledge
    vegetation consists of elemental and organic
                                                      that bushfire smoke was significantly             of firefighters’ exposure to such toxic air
    carbon and can be categorised according to
                                                      associated with increased risk of respiratory     pollutants as carbon monoxide, respirable
    their aerodynamic diameter: coarse particles
                                                      hospital admissions (4).                          particles, polyaromatic hydrocarbons and
    are between 2.5–10 μm (PM10), fine particles
                                                                                                        dioxins.
    are 0.1–2.5 μm (PM2.5) and ultrafine particles    Elsewhere in the world, smoke from the
    are less than 0.1 μm.                             1997-1998 forest fires in Indonesia resulted      It is identifying key toxic pollutants, evaluating
                                                      in substantially reduced air quality over         their concentration and providing tools to
    The coarsest particles in smoke generally
                                                      Malaysia, Singapore, Brunei, southern             measure, evaluate and control the exposure
    settle out from the atmosphere by gravity
                                                      Thailand and parts of the Philippines for         of firefighters and communities to these
    close to the source within hours, the smaller
                                                      a number of months (5, 6). This haze was          substances. The study is monitoring on the
    particles can be dispersed further before
                                                      associated with a significant increase in         fireground at prescribed burns and wildfires.
    settling.
                                                      the number of people requiring clinic
                                                                                                        Respiratory Health of Firefighters
    All particles with an aerodynamic diameter        and hospital treatment for smoke-related
                                                                                                        (Project D 4)
    of less than 10 μm can enter the human            symptoms in some studies (7) but not in
    respiratory tract, but those particles that are   others (8). In the United States, smoke from      This project, now complete, investigated the
    smaller than 2.5 μm are of particular concern     large forest fires have resulted in increased     respiratory effects of combustion products as
    as they are small enough to penetrate deep        hospital visits according to at least three       well as the efficacy of the standard issue smoke
    into the lungs then enter the blood stream        studies (9-11).                                   masks.
    and be transported to other tissues.
                                                                                                        Three types of masks were tested. One mask
                                                                                                        is designed to protect from particulates only,
                                                      Sensitive populations
                                                                                                        and the other two from both particulates and
    Effect of bushfire smoke on                       Most healthy adults and children will             organic volatiles.
    human health                                      recover quickly from acute smoke exposure
                                                                                                        More information on these projects at:
                                                      and not suffer from any long-term adverse
    Smoke has been demonstrated to have                                                                 www.bushfirecrc.com
                                                      consequences. However, there are some
    significant negative effects on human health
                                                      sensitive populations that may experience         See also:
    from studies investigating the impact of
                                                      more severe short- and long-term effects          FireNote 3, Smoke and the Control of
    tobacco smoke, smoke from indoor wood
                                                      from exposure to smoke.                           Bushfires.
    fires and ovens (called indoor biomass
                                                                                                        FireNote 12, Firefighter’s Exposure to Air
    smoke) and industrial smoke in urban              Sensitive populations include:
                                                                                                        Toxics During Prescribed Burns.
    centres (smog). In these studies, exposure
                                                      • individuals with asthma and other
    to smoke is usually investigated at a known
                                                        respiratory diseases, such as chronic
    concentration and for a specified duration.
                                                        obstructive pulmonary disease;
    In contrast, bushfires and prescribed burning
                                                      • individuals with cardiovascular disease
    activities episodically expose humans to high
                                                        including high blood pressure, coronary
    levels of pollutants and for short periods
                                                        artery disease, congestive heart failure or
    of time. The cause-effect relationship of
                                                        angina;
    bushfire smoke is therefore more difficult
    to investigate. The association between           • the elderly as they tend to have pre-
    respiratory illness and community exposure          existing respiratory and cardiovascular
    to smoke from bushfires or prescribed               diseases and reduced immune defence
    burning has been made in a number of                systems against the particulate matter;
    Australian epidemiological studies but a
                                                      • children inhale more air per kilogram of
    causal link is yet to be established.
                                                        body weight and as their lungs are still
    For example, increased levels of particulates       developing, they are more susceptible to
    (PM10) in smoke produced by vegetation              the effects of air pollution.



2      Fire Note: Bushfire Smoke and Public Health