Sources of Indoor Air Pollution

The trend toward greater energy efficiency in homes means homes are sealed up against cold drafts. There is, unfortunately, a downside to tight houses. By sealing them up to keep cold drafts at bay, we also shut down the fresh air that would otherwise cleanse the interior of contaminants. The gasses and particles that pollute the rooms of our houses haven many sources: smoking, burning wood in stoves, operating unvented gas appliances, bathing and cooking, to name a few. Chemicals used for cleaning are other sources. But indoor air pollution comes from items the occupants have no control over. Formaldehyde and organic chemicals  used in the manufacturing of carpeting and building materials gradually release (out gas) air in the room.

Some of the culprits that contaminate the air of our houses are not necessarily unhealthy, simply objectionable. Odors produced in the kitchen and bathroom fall into this category. Others, such as second-hand smoke from cigarettes are definite health hazards. Regardless of contaminant, the occupants will be healthier and happier if it is removed to the outside!

The culprits that contaminate indoor air are many and varied in the potential for damaging health and well being. Here are some of the major offenders in homes.

Radon, a colorless. odorless gas is a radioactive product of the radium that naturally occurs in the earth's crust. Radon poses a risk to people in regions with high concentrations or certain types of rock strata. It is believed responsible for 5 to 15% of all lung cancer. Radon seeps into houses through minuscule cracks in foundations and basement floors and can also occur in water from wells.

Preventing radon from getting into a house is easier at the construction stage than after it is built. Special care can seal up cracks in the floor and walls. Foundations can be waterproofed on the outside. A gravel bed below the basement slab can act as a continuous evacuation path to the outside when it is equipped with a fan that pulls air through the gravel and exhausts it outside.  The homeowner has few means available to mitigate radon in an existing home short of sealing up visible cracks in the foundation and basement slab and installing a ventilation system in the basement.

Formaldehyde is a strong-smelling yet colorless gas embodied in many common building materials, such as plywood and particleboard, as well as furniture, drapes and carpets made from synthetic materials. This gas can irritate the nose, throat and eyes and may cause nasal cancer. Materials that contain little or no formaldehyde should be chosen at the outset. Increasing the rate of air changes in the house helps after the fact.

Combustion Gasses: Several noxious gasses come from operating kerosene heaters, wood stoves and unvented gas appliances. Car exhaust in attached garages can also seep into the house through doorways. Deadly in high enough concentrations, carbon monoxide is a colorless, odorless, tasteless gas produced by burning all fuels. In lesser concentrations this gas can impair the lungs, eyes and brain. Nitrogen oxide has no color or odor while nitrogen dioxide does have an odor at higher levels. Long exposure to either can cause lung damage.

Mitigating pollution from combustion appliance begins at the device. Wood stoves should be properly sized and vented. Appliances should be adjusted correctly. Outside air into wood stoves and fireplaces in preferred to using room air. Chimneys need to be kept clean.  A car should never be left idling in the garage.

Particulates. Smoking releases particles into the air small enough to be inhaled. Minor exposure may result in irritation to the eyes and respiratory system. Long-term exposure can cause emphysema, heart disease, bronchitis and lung cancer. Other sources of particulates include unvented gas appliances, kerosene heaters, asbestos-bearing construction materials and dust. Solutions include not smoking inside, making sure oven doors don't leak, changing air filters regularly and providing an outside air source for combustion appliances.

Gasses from Household Chemicals. Many organic compounds found in cleaning agents, pesticide, aerosol sprays, paints and solvents can irritate the eyes, skin, nose, throat and central nervous system,. Some household chemicals are available in "green" versions that do not harm health. Latex paints, for example, use water as their solvent, rather than solvents derived from petroleum. Other remedies include following the directions on the label, using chemicals only in well-ventilated area and keeping them locked away from children.

You may have noticed that ventilation, in one form or another, is mentioned as a remedy for all the indoor air pollutants. A grasp pf the techniques and devices that provide ventilation will help you achieve clean healthy indoor air.