Why Indoor Air is More Polluted Than Outdoor Air?

It’s the third straight day in a heat spell, with the mercury soaring into the 80s and 90s. The weatherman reports that there’s no relief in sight, noting further that the low pressure front responsible for the temperature spike is also keeping the pollutants from automobiles suspended overhead in a dull brown haze. The air quality index is bad, he tells you. The Environmental Protection Agency (EPA) is urging citizens, whenever possible, to work from home; and further cautioning individuals with asthma or other reactive airway conditions to avoid breathing the toxic air.

When you hear a warning like this, understandably you feel anxious. But did you know that the Environmental Protection Agency has issued similar warnings about the inside of your own home? You may be surprised to learn that much of the time, the air inside your own home can be even more polluted and hazardous to your health than the air outside.

Who’s at risk? People who spend the most time inside their homes, which is to say the very young, the very old, the chronically ill – and their caretakers. Researchers say these individuals may spend as much as 90% of their time indoors. But the rest of us, who spend anywhere between 65% and 90% of our time in our homes, are also at risk.

Sources of Indoor Air Pollution

Lack of Ventilation

What’s the ventilation like inside your home? If you live in those parts of the United States affected by winter, chances are your home is winter-proofed. While insulating, sealing and caulking your home may keep out the chill, these techniques can also make your home so airtight there’s no way indoor dust, tobacco smoke, other combustion products or other pollutants can diffuse into the outer air. That means they stay trapped inside your home – where you inhale them at the risk of your health.

In order to maintain circulation, you will need to increase the amount of outside air coming into your home. Open windows and doors when weather permits. Run exhaust fans in your kitchen and bathroom with outside ventilation system. Make sure all gas appliances like stoves, dryers and water heaters have vents going to the outside, and in the summer time, run your air conditioner with the vent open.

Painting a room? Open a window if you can and make sure the overhead fan is on. It’s particularly important to observe precautions designed to minimize exposure to pollutants any time you use paint, cleaning solutions, pesticides or solvents containing potentially harmful chemicals.

Dust & Dust Mites

The main source of indoor pollution is common dust. For every six rooms in your house (approximately 1,500 square feet), approximately 40 pounds of dust is generated in a single year. Dust is an accumulation of textile fibers from upholstery, drapes, pillows, linens and other furnishings in your home, as well as flakes of human skin, pet dander, animal hair, insects, food particles, pollen, mold spores, insulation – and dust mites.

For every six rooms in your house (approximately 1,500 square feet), approximately 40 pounds of dust is generated in a single year

You may prefer to think of dust particulate as inanimate – but it’s not. It’s home to a veritable plantation of microorganisms including bacteria, viruses and Dermatophagoides pteronyssinus and Dermatophagoides farinae, also known as the common dust mite. It’s been estimated a single gram of dust contains 100 to 500 mites. Dust mites don’t bite, nor do they spread disease, but people with reactive airway diseases are often severely allergic to their droppings.

Dust collects on surfaces, so it stands to reason that the fewer surfaces you have in your house – the fewer knickknacks, books, tables piled high with magazines you haven’t yet gotten around to reading – the less dust you will accumulate. Remove as many dust-collecting items from your house as possible. A vacuum cleaner can actually contribute to your dust problem unless it’s the high efficiency filtering model. Dust mites thrive in moist conditions so be sure get rid of any excess moisture or water in your home. If you use a humidifier, be sure to fill it with fresh water daily, and clean it often according to the manufacturer’s instructions.

Tobacco Smoke

Tobacco smoke is a known carcinogen, as well as a primary factor in the development of chronic obstructive pulmonary diseases. A number of studies have also conclusively linked tobacco smoke to heart disease.

Secondhand tobacco smoke is a combination of the smoke given off by the burning end of a cigarette or a cigar, and the fumes exhaled by smokers. It is particularly dangerous to children whose lungs are immature and still developing, and whose respiratory rates are higher than that of adults. Babies exposed to secondhand smoke have a higher incidence of Sudden Infant Death Syndrome (SIDS). Children exposed to secondhand smoke stand a greater chance of developing asthma (even if they’ve never before exhibited symptoms), suffer from ear infections and develop pulmonary complications like pneumonia and bronchitis. Elderly people exposed to secondhand smoke are at increased risk of developing dementia.

How do you control the harmful effects of tobacco smoke? Stop smoking yourself, and never let anyone smoke within your home or in your car.

Stoves, Heaters, Fireplaces, and Chimneys

Tobacco smoke is not the only product of combustion that may be hazardous to your health. Wood stoves, fireplaces, gas stoves, kerosene and gas space heaters can be sources of carbon monoxide and nitrogen dioxide gas, as well as particulate matter that can lodge in your lungs, causing damage.

Carbon monoxide is a colorless, odorless gas that bonds preferentially with the oxygen receptors within your body, impairing oxygen perfusion. At low concentrations, carbon monoxide can cause symptoms like headaches, dizziness and nausea that can easily be mistaken for the flu; at higher concentrations, it can cause death. Nitrogen dioxide is a reddish brown gas with a distinctive smell that causes shortness of breath.

A persistent, yellow-tipped flame is generally the sign of a malfunctioning kerosene or gas space heater, and is a warning that pollutants are being produced: when the equipment is operating correctly, its flame is blue. Make sure that you’re using the proper fuels and adjusting the heater according to the manufacturer’s directions. Never close the door to a room in which you are operating a space heater; weather permitting, always open the window a crack.

When using a wood stove, make sure that the door is fitted and use cured (dry) wood. Stove hoods with fans venting to the outside reduces your exposure to potentially harmful substances while you are cooking.

Volatile Organic and Inorganic Compounds

Paints, solvents, clothes just back from the cleaners, air fresheners, aerosol sprays can all be sources of pollution from organic compounds.

Formaldehyde, a preservative and bonding agent, is commonly found in particle board and pressed wood furniture. Symptoms of formaldehyde exposure may include watering eyes, nausea and difficulty breathing that manifests as a burning or choking sensation in the throat. To reduce exposure, make sure to ask about the formaldehyde content of any new pressed wood furniture you’re thinking of purchasing, and buy “exterior-grade” particle board whenever possible: exterior-grade pressed wood products contain phenol resins in place of more toxic urea resins.


Radon is a colorless, odorless, radioactive gas, implicated in 21,000 deaths from lung cancer a year according to the EPA. Radon comes from the natural breakdown of small amounts of uranium in water, soil and rock. Radon easily infiltrates building structures. Do-it-yourself radon tests are sold in hardware stores to help people determine whether their homes have been exposed to radon. Professional radon testing is often part of the process of vetting a home that’s been put up for sale. If you smoke and your home is positive for radon, you stand an increased risk of developing lung cancer.

The most effective way of ridding a home of radon is through the use of a soil suction radon reduction system consisting of a vent pipe system and a fan; this is designed to pull radon from the atmosphere inside the home and vent it to the outside. Repairing cracks in your home’s foundation is also highly recommended.

Indoor Pollution: Tips For Apartment Dwellers

Indoor pollution can be just as much of a problem for people who live in apartments as it is for people who live in homes. In most instances, the same preventive steps that allow home dwellers to reduce harmful exposure will also work for apartment dwellers.

In some instances, however – for example, testing for potential radon exposure – an apartment dweller will have to enlist the aid and support of his or her landlord or apartment manager.

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