Indoor Sources of Air Pollution

Tobacco Smoke

There are three hazards related to the smoke produced by smoking tobacco products. Smoke produced by smoking has been found to cause health problems not only for the person smoking but also for those around them, as second hand smoke. The smoke containing particles that settles on the surrounding area is third-hand smoke. The World Health Organization states that there are 4,000 chemicals in cigarette smoke, with 50 shown as carcinogens. It is widely known that tobacco can harm a person's body in many ways that may lead to disease or death.

In 2008, the City of Encinitas prohibited smoking in beaches, parks, trails and outdoor/patio dining areas of eating establishments.


Asbestos is a general name for a group of rock forming minerals that consist of strong and durable fibers. It is mined just like any other mineral. The fibers in asbestos have properties and light-weight qualities that make it a useful material for electrical and thermal insulation. It was often added to building materials for this reason. Buildings built in the last 50 years used a variety of materials composed of asbestos mixed with other fibers such as paper, fiberglass, or synthetic fibers and a binder, usually lime or gypsum mortar. Between 1900 and 1980, an estimated 30 million tons were installed in commercial, industrial and private buildings (Source: EPA).

When disturbed, asbestos crumbles into a dust of microscopic fibers that can remain in the air for a long period of time. If inhaled, they pose a serious health threat, as asbestos fibers can become permanently lodged in body tissues. It is not possible to identify asbestos just by looking at it. It can only be identified by a trained professional with specialized equipment.


Mold is an essential component of our ecosystem – providing decomposition of many organic substances; however, excessive exposure to molds has been the cause of a variety of health effects in humans ranging from minor allergic reactions and exacerbation of asthma, suppressed immune system, to brain damage. Most molds found in indoor air are saprotrophic, meaning they gather their food from dead moist organic matter such as wood, paper, paint, fabric, plant soil, dust, and cooked or raw foods. However, molds can also grow on the surface of damp inorganic matter such as glass. Different types of mold - black mold, toxic mold, allergenic mold - are present all the time around us and in the air we breathe. In low levels, molds and mold spores are generally harmless.

Volatile Organic Compounds (VOCs)

VOCs are a large group of carbon-based chemicals, emitted as gases from certain solids or liquids, that easily evaporate at room temperature. While most people can smell high levels of some VOCs, other VOCs have no odor. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects. There are thousands of different VOCs produced and used in our daily lives. Examples include: paints and lacquers, paint strippers, cleaning supplies, pesticides, building materials and furnishings, office equipment such as copiers and printers, correction fluids and carbonless copy paper, fuels, graphics and craft materials including glues and adhesives, permanent markers, and photographic solutions. All of these products can release organic compounds while you are using them, and, to some degree, when they are stored.

EPA's Office of Research and Development's "Total Exposure Assessment Methodology (TEAM) Study" found levels of about a dozen common organic pollutants to be 2 to 5 times higher inside homes than outside. The studies indicated that product use of organic chemicals exposes themselves and others to very high pollutant levels, and elevated concentrations can persist in the air long after the activity is completed.

Carbon Monoxide

Carbon monoxide (CO) is a colorless, practically odorless, and tasteless gas or liquid. It results from incomplete oxidation of carbon in combustion. At low concentrations, most people will experience fatigue. Acute effects are due to the formation of carboxyhemoglobin in the blood, which inhibits oxygen intake. At higher concentrations, impaired vision and coordination; headaches; dizziness; confusion; nausea; or even death may occur. Sources may include unvented kerosene and gas space heaters, leaking chimneys and furnaces, gas water heaters, gas stoves, generators, and other gasoline powered equipment such as automobiles from attached garages.


Radon is a naturally occurring radioactive gas that cannot be detected with human senses (i.e. it is odorless and invisible). The gas is released during the natural decay of uranium, which is present in most rock, soil and water. Although certain areas of the State are more prone to higher radon levels, radon is a house-to-house issue.

As the radon gas escapes from the ground into the air, the lower air pressure inside your home draws the outside air in through cracks, seams and other openings. Radon is the second leading cause of lung cancer. EPA estimates that nationally 21,000 lung cancer deaths are caused by radon each year.

Much of this content has been adapted from EPA website.