Hybrids
What are Hybrids?
'Hybrids' is our term for pollutants which produce both toxic airborne chemicals
and harmful airborne particles. Aerosols, biological contaminants, and combustion by-products can be placed in this category, as outlined below.
In some cases it is difficult to categorize pollutants consistently, since there are overlapping factors involved which can place them in more than one category.
Aerosol Sprays
The modern increase of body sprays, 'air fresheners',
deodorizing and perfume sprays is heavily contributing
to indoor pollution. These aerosol sprays emit liquid
particles which often contain toxic chemicals.
We have become used to 'improving' the fragrance of our
homes and our bodies with these well marketed products.
However, there is growing evidence that these same products
could be causing headaches, earaches, and the multitude
of other health problems associated
with airborne chemical pollutants.
Biological Pollutants
Where Do They Come From?
Biological air pollutants are found to some degree in every home, school, and workplace.
Sources include outdoor air and human occupants who shed viruses and bacteria; animal occupants
(insects and other arthropods, mammals) that shed allergens; and indoor surfaces and water
reservoirs where fungi and bacteria can grow, such as humidifiers.
Mold—A Primary Example
Mold is a type of fungus. Its spores are particle pollutants which also emit mycotoxins called microbial VOCs (MVOCs). They are known to reproduce very rapidly, and can enter the body
through both the respiratory tract and through the skin. The MVOCs created by the spores are responsible for
the characteristic musty odor associated with indoor mold growth. Microbial VOCs
can be easily measured in the air at very low levels, and
their presence is an indication of indoor mold contamination.
Growth Factors
A number of factors allow biological agents to grow and
be released into the air. Especially important is high
relative humidity, which encourages house dust
mite populations to increase and allows fungal
growth on damp surfaces. Mite and fungus contamination
can be caused by flooding, continually damp carpet (which
may occur when carpet is installed on poorly ventilated
concrete floors), inadequate exhaust of bathrooms, or
kitchen-generated moisture. Appliances such as humidifiers,
dehumidifiers, air conditioners, and drip pans under cooling
coils (as in refrigerators), support the growth of bacteria
and fungi.
Components of mechanical heating, ventilating, and air
conditioning (HVAC) systems may also serve as reservoirs
or sites of microbial amplification. These include air
intakes near potential sources of contamination such as
standing water, organic debris or bird droppings, or integral
parts of the mechanical system itself, such as various
humidification systems, cooling coils, or condensate drain
pans. Dust and debris may be deposited in the duct work
or mixing boxes of the air handler.
Health Effects
The toxic effects of MVOCs range from short-term irritation to severe dermatosis to immunosuppression and cancer.
Mold, bacteria, viruses and other microorganisms in our indoor air can cause infectious and allergic diseases.
Some allergic reactions are severe—asthma is best known and one of the most
serious. Other allergic conditions are subtle chronic conditions. Runny nose, watery eyes, recurring headache,
lethargy, even snoring can all be symptoms of allergy. Many people endure these conditions, not knowing that
they are allergy-related and that prevention is readily available.
Combustion By-Products
Unhealthy by-products of combustion are created by such common activities as cooking. Cooking meat
with fat or oil creates polycyclic aromatic hydrocarbons (PAHs), one of the most widespread types
of organic pollutants. It is very important for your health to vent these fumes outside.
Appliances
Combustion appliances in our homes burn fuel for warmth, cooking
or decorative purposes. Typical fuels are gas, both natural
and liquefied petroleum (LP); kerosene; oil; coal; and wood.
Examples are space heaters, ranges, ovens, stoves, furnaces,
fireplaces, gas water heaters, and clothes dryers.
These appliances are usually safe. However, under certain
conditions, these appliances can produce combustion pollutants
than can damage your health, or even cause death. The health
effects could show up immediately after exposure or could
occur after being exposed to the pollutants for a long time.
Combustion pollutants are gases and particles that come
from burning materials. The types and amounts of pollutants
produced depend upon the type of appliance, how well the
appliance is installed, maintained and vented,
and the kind of fuel it uses.
Some of the pollutants produced from burning these fuels are:
- • carbon monoxide
- • nitrogen dioxide
- • particles
- • sulphur dioxide
- • hydrocarbons
- • aldehydes
Carbon monoxide is an odorless, colorless
by-product of combustion. Inhalation can be fatal with sufficient exposure.
Again we want to stress the importance of ventilation.
Combustion equipment needs an adequate air supply, so furnace
rooms should not be tightly sealed. If the furnace room
has a door, a one to two inch undercut along the bottom
can help to provide needed air.
Don't operate a fuel-fired space heater in an enclosed
space, such as a closed room. Use the proper fuel in kerosene heaters.
Combustion also produces water vapour, which is not usually
considered a pollutant. However, it can result in high humidity
and wet surfaces which encourage the growth of biological
pollutants such as house dust mites, molds, and bacteria.
Wood Smoke
Residential wood heating is a major contributor to winter smog.
Wood smoke also contains harmful chemicals
and gases: nitrogen oxides, carbon monoxide, and VOCs.
Wood is used by millions of North Americans as either
a primary or secondary heat source. Woodstoves and fireplaces
are not only used for heating purposes but also to create
a 'comforting and cosy' atmosphere in the home.
If the combustion of wood were complete, only carbon dioxide (CO2) and water
would be emitted into the air. However, smoke which results
from the incomplete combustion of wood contains a mix of hazardous particles and chemicals that are distilled out
of the wood or formed during its combustion.
If you have to burn, burn smart!
Composition of Wood Smoke
Smoke is a complex mixture of carbon dioxide, water vapor, carbon
monoxide, particulate matter, hydrocarbons and other organic
chemicals, nitrogen oxides, and trace minerals. The individual compounds present in smoke number in the thousands.
Smoke composition depends on multiple factors, including the fuel
type and moisture content, the fire temperature, wind conditions
and other weather-related influences, whether the wood
is fresh or 'aged', and other variables. Different types
of wood and vegetation are composed of varying amounts of cellulose, lignin, tannins and other polyphenols, oils,
fats, resins, waxes, and starches, which produce different
compounds when burned.
Particulate matter is the principal
pollutant of concern from wildfire smoke for the relatively
short-term exposures (hours to weeks) typically experienced
by the public.
Another pollutant of concern during smoke events is carbon monoxide, which
is a colorless, odorless gas produced by incomplete combustion of wood or other organic materials. Carbon monoxide levels
are highest during the smoldering stages of a fire, especially in very close proximity to the fire.
Other air pollutants, such as the potent respiratory irritants acrolein and formaldehyde,
as well as the carcinogen benzene, are present in smoke,
but at much lower concentrations than particulate matter and carbon monoxide.
Reduce Indoor Air Pollution During Wildfires
It is important to reduce other sources
of indoor air pollution during wildfire incidents. Many
indoor sources of air pollution can emit large amounts of
pollutants, some of which are also present in wildfire smoke. Smoking cigarettes, using gas, propane and wood-burning
stoves and furnaces, spraying aerosol products, frying or
broiling meat, burning candles and incense, and vacuuming can all increase particle levels in a home and should be
avoided when wildfire smoke is present.
Frying or broiling some foods can produce high levels of particles in the kitchen
and dining areas. Some of these sources can also increase
the levels of polycyclic aromatic hydrocarbons (PAHs), carbon
monoxide, and nitrogen oxides.
Besides cigarette smoke, combustion sources that do not properly vent to the outdoors (including 'room-vented' or
'vent-free' appliances) contribute most to indoor pollutant
levels, and are of greatest concern.
Thus, reducing indoor air pollutant emissions during smoke events can decrease
indoor particle levels, which may partially compensate for
the increase particle loading from the outdoor air.
Candle Smoke
Scented candles and aromatherapy candles may add to the ambience
of a room and may have a psychologically therapeutic effect, but they
may also be adding toxins to your air.
Metal-core wicks can emit lead into the air which can then be deposited
onto the floor, furniture and walls. As the level of lead
in the home increases, so does the threat to human health,
especially to children, the elderly and people with weak
immune systems.
Lead poisoning affects many organ systems and
biochemical processes, including the central nervous, cardiovascular
and blood systems—and medical treatment does
not fully reverse this effect.
Even when using pure, unscented
wax candles, keep the wicks short to facilitate more complete
combustion which will put less pollutants into the air.
And make sure there is good ventilation to allow carbon
monoxide and carbon dioxide to escape to the outside air.
Tobacco Smoke
Tobacco smoke is a dynamic, complex mixture of more than 4,000
chemicals found in both vapor and particle phases. Many
of these chemicals are known toxins or carcinogens.
Second hand Smoke
Second hand smoke or 'sidestream smoke' can be defined as the mixture of smoke given off by the
burning end of a cigarette, pipe or cigar, and the smoke
exhaled by the smokers. This is also known as 'environmental tobacco smoke' (ETS), and exposure
to ETS is sometimes called 'involuntary or passive smoking'.
All the compounds found in 'mainstream' smoke—the smoke
inhaled by the active smoker—are also found in 'sidestream'
smoke.
Smoking Effects
Tobacco smoke has many health effects: frequent upper respiratory infections;
inflammation of the middle ear, causing severe pain and
high fever which could lead to deafness; asthma onset and
increased severity; recurrent pneumonia, bronchitis, laryngitis. As is often the case
with other effects from airborne pollutants, children, the elderly and individuals
with chronic illness are most susceptible.
The role of exposure to tobacco smoke via active smoking and 'second hand smoking'
as a cause of lung cancer and other
cancers, emphysema and other chronic obstructive pulmonary
diseases, and cardiovascular and other diseases in adults
has been firmly established.
Smoking Facts
Here are a few examples of the chemicals found in tobacco smoke:
- • Benzene (petrol additive) – A colourless cyclic hydrocarbon obtained from coal and petroleum,
used as a solvent in fuel and in chemical manufacture. It is a known carcinogen and is associated with leukemia.
- • Formaldehyde (embalming fluid) – A colourless liquid, highly poisonous, used to preserve
dead bodies. Known to cause cancer, respiratory, skin and gastrointestinal problems.
- • Ammonia (toilet cleaner) – Used as a flavouring; frees nicotine from tobacco turning
it into a gas; found in dry cleaning fluids.
- • Acetone (nail polish remover) – Fragrant volatile liquid used as a solvent.
- • Tar – Particulate matter drawn into lungs when inhaled from a lit cigarette. Once inhaled,
smoke condenses and about 70 per cent of the tar in the smoke is deposited in the smoker's lungs.
- • Nicotine (insecticide/addictive drug) – One of the most addictive substances known to man,
a powerful and fast-acting medical and non-medical poison.
- • Carbon Monoxide (CO) (car exhaust fumes) – An odourless, tasteless and poisonous gas,
rapidly fatal in large amounts. This is the main gas in cigarette smoke.
- • Arsenic (rat poison)
- • Hydrogen Cyanide (gas chamber poison)
Important Note:
Because of the extreme toxicity of tobacco smoke, we strongly
recommend that all smoking should only take place outside and several yards away from a building, where any wind will
carry the smoke away from open doors or windows.
Traffic Pollution Comes Inside
Transportation vehicles, including the personal automobile,
are probably the greatest contributors to air pollution.
Two-thirds of the carbon monoxide emissions come from transportation
sources, with the largest contribution coming from highway
motor vehicles.
Combustion of gasoline and diesel fuel produces hydrocarbons,
nitrogen oxides, carbon monoxide, carbon dioxide and water.
Nitrogen oxides and hydrocarbons are precursors to the formation
of ozone and contribute to acid rain. Carbon monoxide is
a colorless, odourless, poisonous gas.
Asthma is the most common long-term disease in childhood, and
early life exposure to air pollution is associated with
new cases of asthma. Traffic-related pollutants appear to
be especially important.
This information suggests that it is important to consider where daycare facilities and private residences are located if we are to reduce early
exposure to traffic-related air pollution.
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