When we say “air pollution,” what comes to mind? Smokestacks, acid rain, hummers? We don’t often think of the air inside our homes, schools, and workplaces as polluted, but concentrations of certain toxins can often be higher for indoor air quality than they are for outdoor air.

Before you seal off all your windows and replace the front door with a vacuum chamber, know that these toxins probably aren’t blowing in from the outside. In fact, fresh air and ventilation are keys to keeping them under control. Most originate from many of the products and appliances we use everyday. Here are some common indoor air culprits and their sources:

New construction or remodeling

Brand new homes may feel like crisp, clean canvases, but new construction can harbor a host of indoor air pollutants. This is because many materials and products used to build a home, office or any building emit volatile organic compounds (VOCs) long after the paint has dried. “Off-gassing” refers to the release of chemicals from a wide range of products and materials. New carpet (that new carpet “smell”), PVC, adhesives, etc., shed VOCs like formaldehyde, toluene, and trichloroethylene.

Attached garages can also be sources of air pollutants. Parked vehicles can still give off emissions that can sweep into the home from an attached garage. The items that tend to land on garage shelves are also typical sources of indoor air pollution, like paint, oil, varnishes, etc.


Ok, this one isn’t exactly unexpected. If you or someone you live or work with even occasionally smokes indoors, it can cause a spike in indoor pollution concentrations, notably of a VOC called benzene. Exposure to small doses over a long period of time can lead to cancer (Source: CDC). In high enough concentrations, benzene causes symptoms similar to carbon monoxide poisoning, including drowsiness, headaches, confusion, and even death.


Big box and mass-produced furniture is often made from pressed wood or particle board that emits formaldehyde. Upholstery can also emit toxins. Even solid wood furniture that is new or recently refinished can be sources of VOCs from varnishes.

Air fresheners and cleaning supplies

A study conducted to evaluate the toxicity of scented consumer products—including air fresheners, dryer sheets, detergents, all-purpose cleaners, and personal care products—found:

Office Equipment

Office equipment in the workplace, schools, and at home can emit ozone, either through off-gassing of new parts or through general use. This includes printers, fax machines, photocopiers, and computer terminals.


Dampness can lead to mold, especially when combined with warm temperatures. Mold can also produce bacteria, VOCs, and allergens that have been linked to negative health impacts. Take a tour of common mold instigators in the home and learn how to prevent them.

Holding your breath as you look around your home, school or office? Consider these tips to help you improve indoor air quality:

Read more:
Indoor Air Quality Part 2
Indoor Air Quality Part 3