|
Bioaerosols
 |
What are
aerosols and bioaerosols? |
|
|
What are
the sources of biological pollutants? |
|
|
Why do
experts give so much attention to removing bioaerosols
from indoor air? |
|
|
What are
the health effects from biological pollutants? |
|
|
How are
biological contaminants transported through the house? |
|
|
What are
other measures to control these contaminants? |
What are aerosols and bioaerosols?
Aerosols are
substances that are suspended in air, such as tobacco smoke
particulates and the dirt and dust particles that are visible in
a ray of sunlight streaming in through a window. Bioaerosols are
airborne particles from living organisms such as bacteria,
viruses, molds, fungi, pollens, dust mite and insect remains,
and pet dander.
What are the sources of biological
pollutants?
Biological
pollutants, also called bioaerosols, come from plant and animal
material. Some are generated outside the home, such as pollen,
but enter the home through open doors and windows and on people
and pets entering the home.
Other biological pollutants are
generated in the home: mold growth in the home releases spores
into the air; animals generate dander, and insects generate
excrement and body parts that are small enough to become
airborne. Bacteria and viruses are infectious agents that are
brought into the home in a number of ways. All of these
pollutants are particulates -- that is, they are particles so
small that they "float" in the air. Larger particles settle out
onto surfaces, but very small particles stay suspended
indefinitely.
Why do experts give so much
attention to removing bioaerosols from indoor air?
Bioaerosols have been identified as a major source of "Sick
Building Syndrome", infectious diseases, and allergic reactions
such as asthma, pneumonitis, rhinitis, allergic sinusitis,
hypersensitivity, and fatigue. Molds, pollens, dust mite fecal
products, and pet dander are among the leading causes of
respiratory allergic or asthmatic reactions in the indoor
environment.
What are the health effects from
biological pollutants?
Allergic
reactions are the most common health problem associated with
biological pollutants. People differ in their sensitivity to
biological allergens -- some may have no symptoms, while
sensitive persons may have severe health problems. Common
symptoms include watery eyes, runny nose and sneezing, nasal
congestion, itching, coughing, wheezing and difficulty
breathing, headache, dizziness and fatigue.
The most severe reaction to
allergens is an asthma attack, which can be life-threatening.
The American Lung Association reports there are nearly 10
million people in the U.S. with asthma. Of these, over 2.5
million are children. There are over 4,000 deaths each year from
asthma. The number of persons with asthma has been consistently
increasing over the last 15 years. Airborne biological
pollutants present a special risk to people with allergies and
asthma. Note: these pollutants do not cause asthma. Rather,
certain pollutants can trigger an attack in people who have
asthma.
Infectious diseases caused by
bacteria and viruses are generally passed from person to person
through physical contact. Some bacteria and viruses circulate
through indoor ventilation systems.
How are biological contaminants
transported through the house?
Molds and dust mites thrive in similar conditions. Mold
grows on organic materials such as paper, textiles, grease,
dirt, and soap scum. It requires moisture or high humidity. When
a mold colony has been established (for example, on a bathroom
wall), it generates mold spores that float through the air, land
on other surfaces, and if conditions are right, form new
colonies. Mold can also grow in standing water, such as in the
reservoirs of humidifiers or dehumidifiers. Mist from some types
of humidifiers can spread the mold throughout the house.
Dust mites need a food source of
dead human skin cells and high humidity levels. They often
thrive in soft textiles such as bedding, carpet, and upholstery.
When the textiles are disturbed (vacuuming, making beds, or
walking across carpeting), dust mite parts become airborne.
Cleaning surfaces where dust mite particles accumulate can help
reduce concentration in the air. Dust mites have been identified
as the single most important trigger for asthma attacks.
What are other measures to control
these contaminants?
General measures
for controlling airborne contaminants include maintaining and
cleaning heating and air conditioning units, as well as
humidifiers and dehumidifiers. Ventilating homes by opening
doors and windows may be counter-productive for people allergic
to pollens. In homes with ductwork, the standard mesh filter
should be replaced with one offering improved performance.
Allergies to pets may be relieved
by removing pets from the home or keeping pets out of sleeping
quarters. Cats kept in the home should be washed weekly to
reduce the allergen level. Allergen accumulation may be reduced
with the use of vinyl or hardwood floors instead of carpets.
Vacuum with high efficiency filter vacuums or central vacuum
systems to remove dusts which may harbor allergens. Using air
cleaning devices will result in lower levels of biological
contaminants depending on the effectiveness of the devices.
Why do you recommend setting thermostats to the
"On" position rather than "Auto" when bio systems are installed?
Continuous fan operation has been
recommended by HVAC professional for years for optimum occupant
comfort. This is even more important when Central Air Purifiers
are used, to provide continuous, 24-hour-a-day air cleaning. If
an HVAC system is set to the "auto" mode, the fan will run the
least often in the spring and fall months, the times of year
when outdoor allergen levels are typically the highest.
Continuous operation is even more important for bio units
equipped with UV lamps, as frequent on/off cycling can
significantly reduce lamp life.
CO
What is CO?
CARBON MONOXIDE (CO). CO is produced by unvented kerosene and
gas space heaters; leaking chimneys and furnaces; back-drafting
from furnaces, gas water heaters, woodstoves, and fireplaces;
gas stoves. Automobile exhaust from attached garages can also
enter the home. Environmental Tobacco Smoke also produces CO.
What is the effect of CO on your
health?
At low concentrations, some of the effects of CO exposure are
fatigue in healthy people and chest pain in people with heart
disease. At higher concentrations, impaired vision and
coordination; headaches; dizziness; confusion; nausea. CO
exposure can cause flu-like symptoms that clear up after leaving
home. CO is fatal at very high concentrations.
How
does carbon monoxide get into the home?
Carbon monoxide buildup can occur several ways:
|
|
When
flues or chimneys become blocked so exhaust cannot be
vented to the outside |
|
|
When a
fuel burning furnace has a cracked or rusted heat
exchanger, allowing combustion gases into the living
spaces |
|
|
When
fuel-burning space heaters, ovens, ranges or grills are
operated in the home without adequate ventilation |
|
|
When car
exhaust from an attached garage enters the home |
|
|
When
combustion equipment is not working properly and causes
incomplete combustion |
|
|
When
there's a negative pressure balance between the inside
and outside of the home, preventing adequate venting of
combustion gases. |
What
causes carbon monoxide to build to dangerous levels?
Harmful build-ups of these gases can occur when: exhaust from
combustion equipment is not vented to the outside of the home,
and when combustion equipment is not in good working order and
is not regularly inspected for safe operation.
Some homes may have a problem with
"backdrafting." That's when the air pressure inside the home is
less than the air pressure outside, causing combustion
by-products from furnaces, water heaters, fireplaces and similar
equipment to spill back into the room rather than being vented
outside. Backdrafting can also occur when natural draft
appliance exhaust is pulled back into the house by mechanical
ventilation -- like a down-draft kitchen power vent.
Is there a way to detect if my home has carbon
monoxide build-up?
There are carbon monoxide alarms you can install, which will
alert you to dangerous levels of carbon monoxide. It is
important to choose and place an alarm wisely and maintain it to
assure accurate sensing of carbon monoxide.
How can I reduce the risk from carbon monoxide?
The most important practice is to keep all combustion equipment
well-maintained and inspected for safety.
|
|
Experts
recommend having your combustion heating systems
inspected by a trained professional every year. Such
inspections should look for blocked openings to flues
and chimneys; cracked or disconnected flue pipe; signs
of soot around openings in your furnace or boiler; rust
or cracks in the heat exchanger; soot or creosote
build-up; and exhaust or gas odors. |
|
|
Always
operate combustion equipment for its intended purpose
and make sure it has been installed correctly. |
|
|
Never
use unvented combustion appliances indoors. |
Dust Mites
What are dust mites?
|
|
Genus: Dermatophagoides; Mites are Arachnids (members of
the spider family) |
|
|
Species: Dermatophagoides Farinae (DF) - commonly found
in North America |
|
|
Size: About 250 to 300 microns (µm) in length |
|
|
Adult Mite Lifespan: Up to 3 months; (3 larval stages) |
|
|
Reproduction: Female mites lay about 25 to 50 eggs |
|
|
Habitat: Mites live in carpet, fabric upholstery, and
mattresses. |
|
|
Diet: Human skin scale, animal dander and trace
nutrients. Mites need to absorb humidity, they cannot
drink water. |
|
|
Allergen: Dust mite fecal material. |
|
|
Body Color: Translucent. |
|
|
Average Threshold before Developing Allergies: 100
mites/gm of dust |
|
|
Allergic Reactions: asthma, rhinitis |
|
|
Living Conditions: Temp. Range: approx. 59°F to 95° F
(15°C to 35°C) |
|
|
Relative Humidity Range: approx. 55% to 85% |
Number of People in the US Suffering from Allergies: 50 million
and rising.
Dust mites are the most common allergen-producing organism found
in homes. They live in carpets, upholstered furniture, bed
pillows and mattresses. If the relative humidity in your home is
below 50%, dust mites desiccate. If the relative humidity rises
above 50% they strive and reproduce, their appetite increases,
and therefore their fecal matter (the source of the dominant
dust mite allergen) increases. Ninety percent of the population
that experiences any allergy-based symptoms reacts to dust mite
allergen.
What can I do about dust mites?
The best solution is to control the relative humidity in your
home. Dust mites can not survive in areas where the humidity
level is below 50%. Have the relative humidity checked in your
home during summer and fall. Relative humidity can be controlled
by the use of a whole-house dehumidifier installed adjacent to
the air conditioner. By controlling the humidity, you completely
remedy the dust mite problem.
Washing bedding in hot water has been shown to reduce dust
mites. Since stuffed toys are a breeding ground for dust mites,
choose toys that can be washed and thoroughly dried, and keep
them off beds to reduce the exposure received during long hours
of sleep. It may also help to put stuffed toys in the freezer
for a day or so.
Zippered mattress and pillow covers that do not allow the mites
to pass through appear to be effective in reducing the amount of
exposure. While special "allergy" mattress covers are available,
these are expensive. A less expensive alternative is to use a
plastic mattress cover and a mattress pad. Launder all bedding
in hot water (at least 130 degrees Fahrenheit).
It is important to vacuum often to remove dust mite allergens
from carpets and flooring. However filter bags allow small
particles to go back into the air and may actually raise dust
levels in the air. Vacuums with high efficiency filters and
central vacuum systems reduce the airborne dust generated by
vacuum cleaning.
Can I install a dehumidifier in a single room
(such as a bedroom) and achieve the same results for that room?
Yes, to some degree, however the humidity from the rest of the
house will overwhelm the efforts to dehumidify one room and
therefore eventually don't reduce allergen levels significantly.
Why is 50 percent
relative humidity so critical?
The survival of adult dust mites is limited to 4 to 11 days in
relative humidities below 50 percent. Dust mites in the
protonymph stage can survive in this dormant larval stage for
several months waiting for high humidity conditions to return.
Environmental Tobacco Smoke
What is the big deal
about second hand tobacco smoke?
Environmental tobacco smoke, or ETS, contains more than 4,000
volatile organic compounds including more than 40 identified as
carcinogenic (cancer- causing) to humans.
How does secondhand smoke affect my health?
Secondhand smoke has been classified by the U.S. Environmental
Protection Agency (EPA) as a known cause of lung cancer in
humans (Group A carcinogen). The EPA estimates that ETS causes
approximately 3,000 lung cancer deaths in nonsmokers each year.
What are some one the
effect of Environmental Tobacco Smoke (ETS) on children?
Children are especially vulnerable to secondhand tobacco smoke.
|
|
EPA estimates that passive smoking is responsible for
between 150,000 and 300,000 lower respiratory tract
infections in infants and children under 18 months of
age annually, resulting in between 7,500 and 15,000
hospitalizations each year. |
|
|
Children exposed to secondhand smoke are also more
likely to have reduced lung function and symptoms of
respiratory irritation like cough, excess phlegm, and
wheeze. |
|
|
Passive smoking can lead to buildup of fluid in the
middle ear, the most common cause of hospitalization of
children for an operation. |
Asthmatic children are especially at risk:
|
|
EPA estimates that exposure to secondhand smoke
increases the number of episodes and severity of
symptoms in hundreds of thousands of asthmatic children. |
|
|
EPA estimates that between 200,000 and 1,000,000
asthmatic children have their condition made worse by
exposure to secondhand smoke. Passive smoking may also
cause thousands of non-asthmatic children to develop the
condition each year. |
What can I do to reduce my family's risk from
ETS?
Do not smoke in your home or permit others to do so. If a family
member insists on smoking indoors, increase ventilation in the
area where smoking takes place. Open windows or use exhaust
fans. Do not smoke if children are present, particularly infants
and toddlers. They are particularly susceptible to the effects
of passive smoking.
Formaldehyde
Although I familiar with FORMALDEHYDE, I'm unaware
of its sources.
Formaldehyde is an off-gassing from pressed wood products
(hardwood plywood wall paneling, particleboard, fiberboard) and
furniture made with these pressed wood products.
Urea-formaldehyde foam insulation (UFFI) is commonly used in
home construction. Combustion sources and environmental tobacco
smoke produce formaldehyde. Formaldehyde is also used in dry
cleaning, durable press drapes, other textiles, and glues.
What are the effects of formaldehyde on your
health?
Formaldehyde is a strong irritant that causes watery eyes and in
low doses, causes burning sensations in the eyes, nose and
throat. Wheezing and coughing, fatigue, skin rashes, headaches,
loss of coordination and nausea are other symptoms. Larger doses
can cause asthma attacks as well as damage to the liver, kidneys
and the central nervous system. Some people are highly sensitive
and react to formaldehyde concentrations that don't bother most
people. Formaldehyde has been shown to cause cancer in
laboratory animals, but there is limited evidence that it causes
cancer in humans.
What can I do to reduce formaldehyde problems?
|
|
High humidity and elevated temperatures cause
formaldehyde release, so you might want to control
humidity through air conditioning and dehumidifiers. |
|
|
Increase ventilation, particularly after bringing new
sources of formaldehyde into the home. |
|
|
Formaldehyde cannot penetrate plastic laminate and is at
least partly blocked by coatings. |
|
|
Varnishes and special formaldehyde sealants are also
available. Apply these coatings to all exposed edges and
surfaces, such as the undersides of countertops, cabinet
interiors and drawers. |
|
|
When remodeling and in new construction, select low
formaldehyde materials |
Mold
What are molds?
They are microscopic
organisms, found everywhere, indoors and outdoors. Molds are
musty smelling members of the fungi kingdom that feed on organic
materials and thrive in moist conditions. Some fungi are
parasitic and feed off a living host. The saprophyte group of
fungi can produce airborne particles and gases that can cause
musty odors and can lead to illness or allergic reactions. Mold
and mold spores are always present in the outdoor environment
but their volume in proportion to the atmosphere is small.
What is the difference between a mold and a
fungus? What is a spore?
Molds, mildews, and yeasts are various types of fungi. It is
estimated that 25% of all children and up to 10% of adults are
allergic to various fungi such as Aspergillus, Penicillium, and
Stachybotrys. Spores can travel through the air and colonize
distant sites. HVAC systems are the primary way in which molds
and fungi spread and disseminate.
How does mold get indoors?
It travels through the
natural ventilation that occurs in homes and buildings and by
riding on the surfaces of people and materials that enter these
structures. Every time a door opens mold spores will enter the
structure. Molds only require moisture and a food source to
establish colonies and reproduce. They feed on drywall, paper,
and wood or simply dust. Only a short period of high humidity is
necessary to begin the growth of these ever present mold spores
What are some of the common Indoor Molds?
The three most common
indoor molds are Penicillium, Aspergillus, and Stachybotrys:
Aspergillus: This mold can
be seen in several different colors, depending on the species.
Aspergillus can withstand conditions of low moisture and
therefore can be categorized as a xerophilic fungi. It can be a
very toxic mold due to the carcinogens they produce, called
Aflatoxins. These toxins can be especially toxic to the liver,
brain, kidneys, and heart.
Stachybotrys: This mold has
a slimy head and is greenish-black in color. Stachybotrys can
grow on completely saturated surfaces due to its low nitrogen
requirements. It has a high moisture requirement and a broad
temperature range. This high moisture requirement categorizes it
as a hydrophilic type of fungi. Recently, this mold has been
linked to cases of infant respiratory bleeding and several
infant deaths in the Cleveland area and across the United
States.
Penicillium: This mold has a
dense, brush-like appearance with many different branches.
Penicillium tends to emerge at sub-basement levels and rooms. It
can grow in fairly dry conditions, categorizing it as a
xerophilic type of fungi. In addition to the toxins held by the
mold spores, the actual penicillium growths also contain toxins.
These growths can be found almost anywhere, increasing the
threat of this mold in your home.
What are some of the health consequences of
indoor mold?
Indoor mold species
produce a substance including mycotoxins to protect themselves
from other molds and bacteria. Mycotoxins are toxic to humans.
The mycotoxins produced can vary depending on the food source
and growing conditions. Aflatoxin, a mycotoxin from some
Aspergillus strains, is one of the most potent carcinogens known
to man. Ochratoxin-A also from the Aspergillus strain can cause
kidney and liver disease. Beside the serious effects of
mycotoxins, fungi can also infect the human body. Overall
various mold infections can occur in the ear, eye, mouth, sinus,
skin, lung or brain, however, allergies are the most common
health hazard connected with mold growth.
How can I eliminate indoor mold growth and mold
spores?
First you should
eliminate existing visible mold growth and second prevent or
mitigate indoor mold growth. To deal with visible mold growth;
clean it with a disinfectant (a fungicide) that will kill the
mold or remove it. If the growth is spread over several square
feet, removal is recommended. Either method requires protective
clothing i.e. gloves, face mask. To prevent or mitigate indoor
mold growth, products including high efficiency air filters, UV
lights, and dehumidifiers are promoted as services. However
these strategies have different scopes of effectiveness and
therefore a combination of strategies tends to be more effective
in the battle against mold.
What is Black Mold?
Stachybotrys atra (toxic
black mold) is greenish-black in color, slimy and resembles tar
or black paint. The mycotoxin, trichothecenes, is carried in the
mold spores. Typically relatively few spores are released unless
this mold is disturbed. It typically grows only on repeatedly
wetted materials that contain cellulose. These materials can
include wallboard, cardboard, ceiling tile, cellulose
insulation, and any kind of wood. If black mold is growing on
materials that do not contain cellulose, it is unlikely that
Stachybotrys is present.
What are the effects of Black Mold on our
health?
In infants, who are
especially susceptible, there may be lung hemorrhaging or
coughing up of blood; anemia can also be present (although this
infection is not the most common cause of anemia).
Symptoms can occur in
adults as well, and can include breathing problems, rashes,
headache, fatigue and dizziness, nausea, and vomiting and
diarrhea.
Even when this mold has
stopped growing and has dried out, the toxins can still be
harmful.
Once a
mold problem has been identified, how should I go about cleaning
it?
Small areas of mold
(less than a couple square feet) can be cleaned with a solution
of 1 cup laundry bleach to a gallon of water. This can be
applied with a sponge or spray bottle, and rinsed after 15
minutes. Bleach will kill the mold, but does not inactivate the
toxin. Be sure to wear a dust mask, eye protection, and rubber
gloves. Provide plenty of ventilation and keep others out of the
work area. To get rid of the mold for good, it is necessary to
solve the moisture or leakage problem.
NO
What is NO2?
NITROGEN DIOXIDE (NO2). NO2 is produced by kerosene heaters,
unvented gas stoves and heaters. NO2 is also produced by smoking
cigarettes, pipes and cigars (Environmental tobacco smoke).
What is the effect of NO2 on your health?
Exposure to NO2 may cause eye, nose, and throat irritation. It
may also cause impaired lung function and increased respiratory
infections in young children.
Pet Dander
What
is pet dander?
Pet dander is very much like human dandruff. Your pet sheds dead
skin cells which become air borne and are easily inhaled.
Although most people believe they are allergic to an animal's
hair or feathers, it is actually the allergens found in the
dander, saliva and urine that are causing the allergic reaction.
As an animal ages, its shades more dead skin. This may increase
the allergic reaction to your pet as it gets older.
Is it true that a short haired cat
or dog is less allergenic?
Many people are under the mistaken impression that a short
haired cat or dog is non-allergic. This is not true. What you
are allergic to is secreted on the animal's skin and, in
greatest quantities, is found in the animals' urine and saliva.
The reason hair is such a problem is that as the animal grooms
itself the saliva gets all over the hair.
If I keep my pet properly groomed,
will this help reduce my allergies?
Although grooming your pet will not improve your allergies, it
may help to reduce the severity of the reaction. As stated
before, allergens are produced by the animal's dander, saliva,
and urine. Washing your pet twice a week and having a
non-allergic family member brush the pet outdoors will reduce
the amount of allergens to which you are exposed.
We have recently discovered that
our daughter, Gayle, is allergic to our cat, Sam. What steps can
I take to reduce Gayle's allergies without getting rid of Sam?
Pets are now considered family members and it is often difficult
to send them away. However, there are steps you can take to
reduce your daughter's exposure to the allergens produced by
Sam.
|
|
Create
an allergy free zone in the home, preferably in the
bedroom and strictly prohibit the pet's access to it. |
|
|
Clean
frequently and thoroughly to remove dust and dander,
washing articles such as couch covers, pillows, and
curtains. Use a HEPA vacuum cleaner to effectively catch
all the allergens you vacuum up. |
|
|
Wash
your hands after contact with the pet. |
|
|
Non-allergic family members should bathe the pet twice a
week to reduce the amount of allergies the animal gives
off into the environment. Also brush the pet outdoors
and clean out the animal's cage or litter box. |
|
|
Cover
the pet's bed with a washable sheet; wash the sheet by
itself and regularly. |
I recently moved into a new home
and have sense begun having allergy problems. I understand that
the previous home owners had cats. Could this be causing my
allergy to act up?
Yes. Pet dander, especially cat dander, is very volatile and
will stick to almost anything. Getting a cat out of the house
will not get rid of the allergen. If you have carpets, have them
professionally cleaned, or better yet, get rid of them. If the
home came with draperies, these should be cleaned also.
If the allergy problems still exist, more extensive cleaning may
be required. Always check with your Doctor regarding any allergy
problems and steps recommended to relieve these problems.
I understand there may be some
truth behind the saying, Black cats bring bad luck. Is this
true?
Physicians at Long Island College Hospital in Brooklyn, NY,
surveyed 321 patients about how many cats lived with them, how
long they'd owned them, and the color of their cats. The
researchers also graded the severity of each person's allergic
reaction.
They found that patients with dark-colored felines were four
times more likely to have allergic symptoms linked to the pets
than were those who owned light-colored cats. One theory that
will be investigated is whether the fact that the higher amount
of melanin, which accounts for the darker pigmentation, may also
cause higher production of the allergen, therefore, more
allergic reactions.
This study is still underway.
|
