Your dream living room...or is it?
Environmental agencies and scientists seem to agree that however hard we try, it is almost impossible to totally eliminate or even evaluate indoor pollution.
The World Health Organization (WHO) estimate that 4.3 million people a year die from exposure to household air pollution.
From cooking on wood fires in poorly ventilated dwellings to the overuse of chemicals fed by an obsession with hygiene, the potential health problems stemming from indoor pollution range from sneezing to cancer.
The US Environmental Protection Agency (EPA) define indoor air quality (IAQ) as "the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants."
This article will look at some of the issues relating to air pollution in the home.
How sick can you get from indoor air pollution?
Do you find that your eyes, nose and throat become irritated, your head aches, you feel dizzy or fatigued after spending time indoors, only to discover that, on leaving the house, they disappear? These could be the short-term effects of indoor air pollution.
Reactions to pollutants depend on a number of factors, including age, individual sensitivity and existing conditions. Children, pregnant women, elderly people - who, one study says, spend an average of 19-20 hours a day indoors - and those with cardiovascular or respiratory diseases tend to be more susceptible.
The new sofa looks chic, but it is triggering your asthma?
Some substances, like lead or tobacco smoke, may affect children more than adults. Children are more likely to have asthma, too, which can be exacerbated by indoor pollution.
Pollutants with immediate effects can be dangerous, but they are often easy to recognize and remove.
Long-term effects, such as chronic respiratory conditions, heart disease and cancer, can take years to manifest. By then, it may be too late.
With more than 900 chemical substances potentially floating around American homes, knowing what causes a problem and how to regulate it can be a minefield.
First, there is no such thing as a "typical indoor environment." Each home contains a different and complex mix of potential pollutants that change with time. Individuals also have different reactions.
Second, even if scientists can analyze one substance, combinations interact differently, potentially causing more, or less, noxious effects than each chemical does on its own. Very little is known about the combined effects of indoor air pollutants.
Common pollutants include mold, dust and dander, insects, tobacco smoke, cleaning products and pesticides, gases such as radon, nitrogen dioxide (NO2), carbon monoxide (CO) and building materials, such as formaldehyde and lead. Furniture, floor coverings and air conditioners or heaters can also harbor particles of pollution.
Where do they come from and what do they do?
Mold, damp and ambient temperature
Dryness, humidity, lack of ventilation and high or low temperatures increase the risk of indoor air pollution.
High temperatures and dryness can cause eye and skin irritation, rashes, dry skin and dry nose.
Airtight windows give rise to damp and mold.
Damp can come from leaks, condensation or the ground. It lurks in ill-ventilated kitchens - where steam is released from cooking - in bathrooms, after a shower, or in places where laundry hangs up to dry.
It promotes the growth of microorganisms such as molds and bacteria that release pollutants into the air.
These can enter the respiratory system, causing irritation of the mucous membranes, breathing problems and infections or diseases such as asthma and allergy.
Weatherizing has been promoted in recent years to reduce fuel consumption, but it also decreases ventilation, trapping humidity inside and exacerbating indoor pollution.
If you are planning on weatherizing but already have signs of indoor pollution, the EPA recommend dealing with these first.
Signs to look out for include moisture or condensation on walls or windows, smelly or stuffy air, dirty central heating or air cooling equipment and mold in ill-ventilated areas.
Medical News Today previously published an article giving more details on the dangers of mold in the home.
What about air purifiers?
Designed to kill mold and bacteria, air purifiers produce large amounts of ozone.
When inhaled, ozone can react chemically with biological molecules in the respiratory tract, leading to adverse health effects, such as reduced lung function, inflammation of the airways, coughing, wheezing and, in severe cases, death.
Ozone is a key component of smog. Do we want it in our homes?
Dust is really any kind of waste particle, from outdoor soil to fibers from bedding to flakes of skin or insects. Dust can include lead particles, mold spores, animal dander, insect feces and other pollutants.
Skin rash? It could be a cockroach allergy.
Pets and pests, such as dust mites, cockroaches and mice, are important indoor sources of allergens, leading to diseases of the airways, rhinitis and asthma.
Cockroaches contain potent allergens, and their waste and bodies are a common cause of asthma and allergic reactions, such as skin rashes.
Not only do curtains, carpets and soft furnishings trap dust, but toxic gases in the air can stick to small particles, which enter the lungs on becoming airborne during vacuuming, sitting on the couch, or walking or playing on the carpet.
To minimize the dangers of dust, the American Lung Association (ALA) recommend using a high-efficiency particle air (HEPA) vacuum cleaner at least three times a week and avoiding carpets where possible, especially in places prone to mold.
When dusting, use a damp cloth where possible to remove particles rather than just moving them on.
Tobacco smoke contains more than 7,000 chemicals; hundreds are toxic and about 70 are carcinogenic.
In adults, passive smoking can cause irritation, aggravated respiratory symptoms and coronary heart disease.
In children, it can also lead to ear infections and sudden infant death syndrome (SIDS).
The Centers for Disease Control and Prevention (CDC) estimate that since 1964, approximately 2,500,000 non-smokers have died from health problems caused by exposure to secondhand smoke in the US.
Cleaning products and pesticides
Cleaning and floor care products, air fresheners, glues, paints, paint strippers, personal care products, printed matter, electronic equipment, candles and incense, to mention just a few, contain innumerable chemicals or combinations of chemicals that can be hazardous.
The short- and long-term effects of household chemicals can be severe.
Many household cleansers contain powerful and often toxic solvents, antibiotic pesticides and other chemicals, and they can emit chemicals.
Chlorine laundry bleach at either 5.25% or 6% strength sodium hypochlorite is approved by the EPA for surface cleaning, to help prevent the spread of infections in homes.
However, it can be dangerous if used incorrectly. Mixing a chlorine-based cleanser with an acid-based cleanser - like vinegar or ammonia, for example - can produce toxic chlorine gas, causing irritation and burning to the eyes, nose and throat. Avoid using one after the other on the same surface.
Terpenes, released by air fresheners, interact with ozone to form formaldehyde and acetone at concentrations that can cause respiratory sensitivity and airflow limitation.
Many chemicals in household products are thought to incur serious health conditions over time, but specific information is often lacking.
The long-term effects of organophosphate pesticides have been documented. Commonly used as an insecticide in the home, it can affect the central nervous system, possibly causing developmental problems in children.
Phthalates, found in most air fresheners, have been shown to disrupt hormone function in infants and children and to interfere with reproductive development.
Using candles instead? Beware: most candles are made with paraffin wax and contain benzene and toluene, both linked to cancer. Scented candles can trigger allergies or migraine. If the candle is scented with essential oils, check the origin first. Alternatively, look out for unscented candles made from soy or beeswax.
The National Resources Defense Council (NRDC) recommend replacing toxic household cleansers, where possible, with commercially available "green" alternatives or traditional cleaning recipes using vinegar, lemon juice and baking soda. Needless to say, all chemicals must be kept away from children.
Gases: radon, nitrogen dioxide and carbon monoxide
Radon is a colorless, odorless, radioactive gas that occurs naturally in some places and can enter homes, for example, through basements or cracks in walls. It is the second leading cause of lung cancer in the US, believed to kill 21,000 people annually. MNT recently published a Knowledge Center article giving more information about radon.
Come home to a real fire, but beware of the soot.
The federal government recommends using an inexpensive and easily available EPA-verified radon detector to measure the level of radon at home.
The EPA can provide further information about risks associated with different levels of exposure and suggest measures to reduce radon levels in the home.
CO and NO2 result from burning gas, wood or fossil fuels in heating systems, stoves and other home appliances.
CO is deadly poisonous, an odorless, colorless and toxic gas that can kill you before you know it is there. It can leak from unvented or damaged heaters. A CO detector/alarm can let you know if the levels of CO in the air are too high.
NO2 can trigger asthma attacks and other respiratory illness. Recent research reported by MNT has linked it with skin aging, specifically the development of lentigines, or liver spots.
Burning fossil fuels also produces carbon particles or soot. These have been associated with eye and respiratory problems, decreased immune function and more recently skin aging. Even after the fire goes out, the soot collects in dust and continues to pose a hazard.
Prof. Jean Krutmann, of Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany, told MNT:
"You can have [a lot of carbon particles] at home, during Christmas time, when you burn a lot of candles."
Prof. Krutmann and colleagues recently found that in China, cooking with fossil fuel is associated with a 5-8% higher incidence of facial wrinkles and 74% more fine wrinkles on the backs of the hands.
While keeping warm in winter, remember to ventilate, especially when burning any kind of fuel.
Furniture and flood coverings: VOCs and formaldehyde
Volatile organic compounds (VOCs), such as benzene, formaldehyde and naphthalene, are emitted by many consumer products. They also react with ground-level ozone to form secondary pollutants that then cause irritation.
Laminate floors reduce dust but can off-gas chemicals.
In hot or humid conditions, formaldehyde can "off-gas" from carpets and wood products, including cabinets, shelving and laminate flooring.
As the chemical is released, it can irritate the nose and throat, trigger asthma attacks and other lung damage and potentially promote cancer.
The US Consumer Product Safety Commission (CPSC) recently issued new guidelines on formaldehyde products, and the EPA specify the safety standards to look out for.
Furniture that was purchased before 2006 will almost certainly contain flame-retardant polybrominated diphenyl ethers (PBDEs). PBDEs are no longer used because they can emit carcinogenic toxins into the air.
But is your new armchair any safer? One PBDE substitute, brominated tris (TDBPP), was banned from use in children's pajamas in 1977 after research showed it could damage DNA.
Lead, paints and solvents
Lead paint has been prohibited in the US since 1978 but is still present in older houses. As it deteriorates and cracks, it can get onto children's hands and into their mouths.
The CDC state: "No safe blood lead level in children has been identified. Even low levels of lead in blood have been shown to affect IQ, ability to pay attention, and academic achievement. And effects of lead exposure cannot be corrected."
Many new paints, although lead-free, release VOCs. Ventilation is, therefore, essential to reduce the harm from off-gassing. Low-VOC or no-VOC paint is also available.
Hobbies involving paints and glues are best practiced outside, or with open windows. A solvent known as "glymes," used in inkjet printers and circuit boards, is linked to developmental and reproductive damage.
What is the answer?
The chemicals, particles and biological materials that populate the indoor environment are easily inhaled, can pass into the bloodstream, and some even cross the blood-brain barrier. If anyone experiences symptoms resulting from indoor air pollution, the EPA suggest consulting a physician or a board-approved allergist.
If the problem seems serious enough to warrant testing for pollutants, the EPA suggest contacting the local health department first, because testing can be costly.
To some extent, consumers can minimize the presence of noxious chemicals in the home by choosing non-toxic, "green" versions of many products.
But the most immediate and effective solution is good, old-fashioned ventilation. An article published last year by MNT reported that air exchange rates in today's airtight homes are now only 0.1-0.2 per hour, compared with approximately one change per hour in 1970.
Now, how about opening that window?