Achoo! Are You Allergic to Your Home?
House dust! How bad can it be? Well, the EPA ranks indoor air pollution among the top five environmental risks to public health. It is estimated that up to 50 million Americans are affected by allergies each year, with 11 million of these experiencing asthmatic symptoms. This accounts for approximately 16.7 million doctor visits and $18 billion in medical expenses each year. Since Americans spend about 90% of their time indoors, it is not surprising that the rate of asthma and allergies are on the increase!
The most common health effects revolving around allergens are allergic reactions, asthma, dermatitis, and conjunctivitis. Every individual has different levels of sensitivities and may not be allergic to certain allergens. The most common symptoms of an allergic reaction include sneezing, watering or itching eyes, scratchy throat, runny nose, tissue inflammation, shortness of breath (asthma) and skin irritation.
Allergens consist of chemical or biological substances that produce an allergic response in some individuals. And house dust contains some of the common asthma and allergy allergens. In fact, polluted air and dust can contain mold spores, pollen, chemicals and perfumes. It can also contain the three most common allergen sources for asthma and allergies - pet dander, dust mites, cockroaches and their wastes.
Pet dander is a major problem. In America, the effects of animal dander are higher than elsewhere in the world because most of us keep our pets indoors. In fact, 63% of U.S. households own a pet which equates to 69.1 million homes.
Dogs, cats, rodents – including hamsters and guinea pigs- and other mammals can trigger asthma in individuals with an allergic reaction to animal dander. The proteins in dead skin, saliva, dandruff and urine from an animal are the cause of allergies, not the animal’s hair. And short haired dogs are no less allergenic than longhaired dogs.
Cats are very allergenic – with the highest concentration of allergens on their necks. People who own cats are likely to carry allergens on their hair, skin, and clothing. High levels of cat allergens have been found in offices of people who keep cats at home.
Animal allergies also carry over to related products such as down comforters, wool and mohair sweaters, fur coats, and horsehair upholstery.
Dust mites are closely related to spiders and ticks. They are invisible to the naked eye and are so tiny that they float into the air whenever you fluff a pillow, pat a stuffed animal or walk across a carpet. They are in every home! Approximately 50% of allergy sufferers react to dust mites and that number is rising. In fact, dust mites can cause asthma in children who have not previously exhibited asthma symptoms.
Dust mites feed on human skin flakes, (humans continually shed skin and lose about 1/5 ounce of dead skin each week),
pollen, fungi, bacteria and animal dander. As dust mites grow, they shed their skin. It is their skin particles and feces that cause allergic reactions in people. During their life span, dust mites have been reported to produce feces weighing up to 200 times their body weight. About 42,000 dust mites can live in 1 ounce of dust. Dust mites live for up to 100 days and during that time lay up to 70 eggs. Thus, just a few dust mites can quickly lead to a significant infestation.
Clinical studies have determined that dust mites can cause allergic reactions, asthma, dermatitis, and conjunctivitis in affected individuals. About 10%-20% of the population is allergic to dust mites. Dust mites thrive in mattresses, pillows, carpets, upholstered furniture, bedcovers, clothes, stuffed toys, car seats and fabric-covered items. For example, the average year-old pillow contains 250,000 dust mites.
Cockroaches are the most common insect to evoke an allergic response. In the United States, the German cockroach is one of the most prevalent species. Cockroach allergens are released from their saliva, fecal matter, skin shells, and their eggshell. As with other allergens, cockroach allergens are small enough to become airborne with ordinary traffic through a room. A concentration of 2 units of German cockroach allergen per gram of dust has been found to produce an allergic reaction in some individuals.
Tackling the Dust
Reducing exposure to indoor allergens can reduce asthma and allergy symptoms. One solution is to properly ventilate your home. As important as energy efficiency is, an insulated home retains forty times more pet allergen than a non-insulated home. Air filters help but pet emanations are remarkably durable and can stay in furniture, carpets, draperies and heating ducts for as long as six months.
We spend about one third of our lives sleeping. Therefore high levels of dust mites are often associated with the bedroom - especially bedding and mattresses. Since dust mites dislike plastic and low humidity, cover mattresses and pillows with dust proof zippered covers. Wash bedding once per week in hot water, at least 77 deg F. Try to keep the humidity below 60% and replace feather pillows with synthetic ones. Also, choose washable stuffed toys and wash them often in hot water and dry thoroughly. Keep stuffed toys off beds.
Select appropriate furnishings- avoid overstuffed furniture, wool fabrics and rugs because wool sheds particles that are eaten by insects. Use washable curtains and rugs instead of wall to wall carpeting. If you cannot replace the carpeting, have it steam cleaned at least once a year-Springtime is best.
The vacuum cleaner is an important tool for managing house dust. However, dust the furniture before you vacuum so the dust has time to settle on the floor where it can be picked up by the vacuum. Do not scatter dust. Instead, dust with a damp cloth rather than dry dusting.
Vacuum cleaners with a water filter are preferable to those with a disposal paper bag because the water vacuum removes a greater particle size than paper-bag types. There are also vacuums with high efficiency particulate air filters (HEPA filter) designed for use by people allergic to dust.
It is better to vacuum thoroughly once a week rather than lightly on a daily basis. Vacuum mattresses and padded furniture thoroughly -20 minutes for each mattress is not too long.
A major reservoir for collecting and holding dust in indoor environments is carpeting. Carpets accumulate allergens at 100 times the rate of a bare floor. The ideal non-allergenic flooring is hardwood, tile or vinyl since these surfaces can be cleaned with a wet mop and covered with small washable rugs.
The most effective method to control animal allergens in your home is to keep pets out of the house and always groom them outdoors. (Note-other countries experience much lower rates of allergies and asthma because most pets are kept outdoors.)
If you remove an animal from the home, it is important to clean the floors and walls, carpets and upholstered furniture thoroughly. Pet allergen levels are reported to stay in the home for several months after the pet is removed even with cleaning.
If your pet resides in the home, some experts advise you to wash your pets regularly. On the other hand, washing may only provide a temporary reduction in allergen levels. There is no evidence that this short term reduction is effective in reducing symptoms and it has been suggested that during the washing of the animal the sensitive individual may be initially exposed to higher levels of allergen.
If you want to keep your pets indoors, one solution is to make your bedroom off-limits to pets. Bathe them with a mild shampoo at least once a week to reduce dander. Despite these precautions, several reports indicate that animal allergen is carried in the air and by residents of the home on their clothing to all parts of the home, even when the animal is isolated.
If you have a forced –air heating and/or cooling system in your home, you have another source for generating dust. With forced-air systems, it is important to use at least pleated filters rated for the blower capacity and to clean them often.
According to the University of Texas research, HEPA air filters are much more effective in removing dust than ion-generating air purifiers which make particles electrically charged to remove them from circulating air. Some ion-generating air filters emit significant amounts of ozone. Ozone irritates the lungs and can cause chest pain, coughing, shortness of breath and throat irritation. According to the EPA, ozone may worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections.
Forced - air systems can have leaky ducts. It is not uncommon to find about 20% of the air that goes through a typical forced-air system is lost through holes and gaps around the fittings or from unsealed joints between duct sections. These leaks let heated or cooled air escape and draw dirty air into the system. (Heating contractors can pressure-test your system-if more than 2% of the air is leaking out, it is worth sealing every accessible joint)
So how bad is your house dust? The International Association of Allergology and Clinical Immunology (IAACI) recommends collecting settled dust to evaluate the exposure of occupants to common allergens.
Threshold values have been proposed from numerous studies on allergens in dust. These threshold values are levels at which there is an increased risk of allergy sensitization or reactions in sensitized individuals. Indoor levels should be less than the following levels:
Dust Mite 2 micrograms/gram
Cat 8 micrograms/gram
Dog 10 micrograms/gram
Cockroach 2 units/gram
An allergen screening can be used to determine the cause of allergic symptoms in your home or to help you make your decision when moving to a new location.
The best way to determine if the dust allergens in your home are above threshold levels is to hire a professional to conduct allergen screening. If it is determined that there are allergens above the threshold levels, corrective measures can then be implemented.
Peter Ottowitz, Hawkeye Home Inspection & Environmental Testing
Certified Master Inspector
Certified Environmental Home Inspector
Certified Residential Mold Inspector
Licensed Construction Supervisor
CMC Certified Energy Auditor
Level One Thermographer