20-5 Indoor Air Pollution

How Serious Is Indoor Air Pollution? Being Indoors Can Be Hazardous to Your Health

Studies have revealed some alarming facts about indoor air pollution:

  • levels of 11 common pollutants generally are 2–5 times higher inside homes and commercial buildings than outdoors and as much as 100 times higher in some cases.

  • pollution levels inside cars in traffic-clogged urban areas can be up to 18 times higher than outside.

  • the health risks from exposure to such chemicals are magnified because people typically spend 70–98% of their time indoors or inside vehicles.

As a result of these studies, indoor air pollution is near the top of the list of sources of cancer risks— causing as many as 6 000 premature cancer deaths per year in North America. At greatest risk are smokers, infants and children under age 5, the old, the sick, pregnant women, people with respiratory or heart problems, and factory workers.

According to public health officials, the four most dangerous indoor air pollutants in developed countries are cigarette smoke, formaldehyde, radioactive radon-222 gas, and very small fine and ultrafine particles. Good news. In recent years, a growing number of cities in Canada and other developed nations have elected to ban indoor smoking in facilities used by the public

Are You Exposed to Formaldehyde? A Serious Problem

The chemical that causes most people in developed countries difficulty is formaldehyde, a colourless, extremely irritating gas widely used to manufacture common household materials.

There are many sources of formaldehyde. They include building materials (such as plywood, particleboard, panelling, and high-gloss wood used in floors and cabinets), furniture, drapes, upholstery, adhesives in carpeting and wallpaper, urethane- formaldehyde insulation, fingernail hardener, and wrinkle-free coating on permanent-press clothing.

Case Study: Are You Being Exposed to Radioactive Radon Gas? Test the Air in Your House

Radon-222 and Lung Cancer Risk Summary:

  • What is Radon-222?

    A colorless, odorless, tasteless radioactive gas formed by the decay of uranium-238, which is naturally found in soil, rock, and especially concentrated in minerals like uranium, phosphate, granite, and shale.

  • Health Risk:

    Radon is the second leading cause of lung cancer in the U.S., after smoking. It causes ~14,000 lung cancer deaths annually, including 2,100–2,900 in non-smokers.

  • How It Enters Homes:

    Radon seeps up through soil and enters buildings through cracks, drains, and openings. It accumulates indoors, especially in basements or poorly ventilated areas, due to lower air pressure inside homes.

  • Radiation Hazard:

    Radon decays into radioactive solids like polonium-210. Inhalation exposes lung tissue to ionizing alpha radiation.

  • Scientific Assumptions:

    • No safe threshold dose for radon exposure.

    • Risk estimates are based on data from uranium miners and extrapolated to home exposure levels—though some scientists question this method.

  • Detection & Prevention:

    • Radon hot spots are unpredictable; testing is the only way to detect it.

    • Long-term monitoring (2 months–1 year) in main living areas is ideal.

    • Mitigation: Seal foundation cracks, increase ventilation, and use fans for cross-ventilation.