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A Guide to Indoor Air Quality (IAQ)

  • Written by: TruSens

Woman sitting on a couch with her arms behind her head and eyes closed.

When we clean our homes or consider our homes as ‘clean’ it is typically after all the dust, pet hair and more has been swept, wiped or vacuumed away. Although this may be a good way to keep our homes clean on the surface, how clean does this keep the air were breathing in?

It’s easier to understand why we need to dust or vacuum but taking care of you air often means worrying about what you may not see or smell. “Most of the things that cause problems are odorless,” says Dr. Nicholas BuSaba, associate professor of otolaryng-ology at Harvard-Medical School. "So, in many cases there's nothing to alert you to the problem.”

What Are Indoor Air Pollutants?

Indoor air pollutants can come from a long list of potential sources and affect the indoor air quality of homes, apartments, schools, commercial buildings and other indoor facilities. “These include combustion sources such as oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deteriorated, asbestos-containing insulation, wet or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; central heating and cooling systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution.” (CPSC)

Health Effects from Poor Indoor Air Quality

IAQ may vary based on location, but without proper management each location has potential to pose health effects. According the Environmental Protection Agency (EPA), “The link between some common indoor air pollutants and health effects is very well established.” Health effects caused by poor IAQ may be experienced soon after exposure or even years later.

Effects of exposure may vary based on the pollutant they are exposed to, the length or number of times exposed, age or pre-existing medical conditions.

Immediate Effects:

Less-severe symptoms mirror those of a cold or viral infection, making it difficult to determine the direct cause. If the source of the pollution can be identified, treatment to immediate effects may include simply eliminating the person’s exposure.

  • Irritation of the eyes, nose, and throat
  • Headaches
  • Dizziness
  • Fatigue
  • Symptoms of some diseases such as asthma may show up, be aggravated or worsened

Long-term Effects:

Other effects from indoor air pollutants may show up either years after exposure or only after long or repeated periods of exposure. Long-terms effects can be severely debilitating or fatal in some instances.

  • Respiratory diseases
  • Heart disease
  • Cancer

How to Identify Issues with Indoor Air Quality

Identifying issues with IAQ is especially challenging due to the inability to see or smell many airborne pollutants. While there are ways to test for certain pollutants, other pollutants aren’t as easy to identify. Below, we have listed ways to identify issues with indoor air quality.

  • Determine correlations to changes in a home environment. If symptoms appear in relation to a change in your living environment such as moving to a new place, remodeling or pesticide treatments, this may be a red flag alerting you to the source of your problems. Since this is not a definitive answer a next step to resolution may be to see a doctor for testing.
  • Identifying potential sources of air pollutants in your home. These sources may not be currently emitting pollutants, but it is good to take note and preventative measures in case they develop into a source in the future.
  • Test for any pollutants that can be tested for. For example, detection of radon within an indoor space can be determined by testing the air.
  • Investigate your lifestyle. The activities we participate in or lifestyle choices also contribute to emission of pollutants. Establish which activities you do that may contribute to poor indoor air quality in your home. See the next section for more information on how your lifestyle may contribute to poor indoor air quality.

Is Your Lifestyle Affecting Your Indoor Air Quality?

The quality of our indoor air is constantly affected by what we do. The level and type of pollutant sources within our indoor air can vary based on our unique lifestyle. Below are some of the activities that may be affecting your indoor air quality.  

  • Cleaning or disinfecting your living space typically has more positive effects on indoor air quality than negative. However, many cleaning and disinfectant products contain chemical pollutants. It is important to regularly clean, but in some cases, it solves one problem while adding to another.
  • Renovations may improve the appearance of the space but lower the quality of your indoor air. Products such as paint, varnishes and wax all contain organic solvents and may “release organic compounds while you are using them, and, to some degree, when they are stored.” (CPSC)
  • Gas stoves have the potential to emit pollutants like formaldehyde, carbon monoxide (CO), and nitrogen dioxide (NO2). An improperly vented or adjusted gas stove makes matters worse. “An improperly adjusted gas stove can emit significantly more carbon monoxide than one that is properly adjusted.” (CPSC)
  • Older buildings or houses often contain products that may have since-then been discovered to be problematic. In more recent years, products containing asbestos or lead have been banned, but older buildings and homes still have these products. In the past asbestos was commonly used in a variety of building construction materials for insulation and as fire-retardant. Lead had been used in paint, gasoline, water pipe, and other products, before it was found how harmful lead could be.
  • Smoking tobacco products such as cigarettes, pipes or cigars indoors should be avoided when possible. If smoking indoors cannot be avoided, increase ventilation where smoking is occurring. “Because smoking produces such large amounts of pollutants, natural or mechanical ventilation techniques do not remove them from the air in your home as quickly as they build up.” (CPSC)
  • Showering too long or without an exhaust fan on, leaving spilled water, and more could lead to a buildup of biological contaminants. Humidity, standing water and wet surfaces are breeding ground for molds, mildew and bacteria.
  • Owning a pet should come with an understanding of the biological contaminants they bring. Animal dander is shed by pets and becomes part of your indoor air.
  • Fireplaces, chimneys and flues may release combustion gases and particles if improperly installed, maintained, or used. Fireplaces without a dedicated source of outdoor air may have pollutants come back into the home, contributing to poor indoor air quality.
  • Pesticides such as insecticides or disinfectants are commonly found infiltrating indoor air, increasing human exposure. A “study suggests that 80 percent of most people's exposure to pesticides occurs indoors and that measurable levels of up to a dozen pesticides have been found in the air inside homes.” (CPCS)
  • Automobile exhaust contains carbon monoxide. Storing an automobile in an attached or underground garage may allow the emissions to spread into the house or building

Strategies to Combating Poor Indoor Air Quality

Manage sources

One of the most effective ways to combat indoor air pollutants is to eliminate or reduce emissions straight from the source. Managing the source will depend on the pollutant. For example, sources of asbestos can be sealed or enclosed, while sources like gas stoves can be adjusted to decrease the amount of emissions.

Improved ventilation

Improving the ventilation within your indoor space, allows the indoor air pollutants to be released into outside space. “If too little outdoor air enters indoors, pollutants can accumulate to levels that can pose health and comfort problems. Unless buildings are built with special mechanical means of ventilation, those designed and constructed to minimize the amount of outdoor air that can "leak" in and out may have higher indoor pollutant levels.” (EPA) Outdoor air entering into an indoor space can happen in several ways, including:

  • “through natural ventilation, such as through windows and doors
  • through mechanical means, such as through outdoor air intakes associated with the heating, ventilation and air conditioning (HVAC) system
  • through infiltration, a process by which outdoor air flows into the house through openings, joints and cracks in walls, floors and ceilings, and around windows and doors.”

Most residential heating and cooling systems do not mechanically bring outdoor air inside. When weather permits, opening doors and windows, or running fans or window air conditioners is a simple way to increase ventilation and allow fresh air in. “It is particularly important to take as many of these steps as possible while you are involved in short-term activities that can generate high levels of pollutants--for example, painting, paint stripping, heating with kerosene heaters, cooking, or engaging in maintenance and hobby activities such as welding, soldering, or sanding. You might also choose to do some of these activities outdoors, if you can and if weather permits.” (Consumer Product Safety Commission, CPSC)

Improving your ventilation may vary based on what you have already established within your indoor space. Within a kitchen, there should be an exhaust fan over gas cooking stoves and ranges. Bathrooms should also have an exhaust fan in order to prevent excess moisture buildup. With any fireplace, a flue should be properly installed and open while the fireplace is in use.

Air cleaning technology

Using air cleaners and air filters in the home is recommended by the Environmental Protection Agency (EPA). Air cleaners coming in all shapes and sizes from table-top models to whole-house systems, there are plenty of options when choosing the best one for you. “Using a portable air cleaner and/or upgrading the air filter in your furnace or central heating, ventilation, and air-conditioning (HVAC) system can help to improve indoor air quality. Portable air cleaners, also known as air purifiers or air sanitizers, are designed to filter the air in a single room or area. Central furnace or HVAC filters are designed to filter air throughout a home.” (EPA)

Avoid High Indoor Temperatures and Humidity

Avoid high indoor temperatures and humidity to prevent or reduce biologicals, formaldehyde and biological contaminants from polluting your indoor air. Keeping the thermostat at a moderate temperature and proper ventilation can help to address these issues in your indoor space.

“Also consider a dehumidifier in damp areas, such as a basement, to help prevent the growth of mold. Ensure that bathrooms, another potential source of mold, are well ventilated as well and scrub off any visible mold that collects in the shower, on fixtures, or walls.” (Harvard Medical School)

Change Your Filters

Even if you have taken steps to improve indoor air quality through mechanical ventilation or air cleaner technology, those systems are not going continue to help indoor air quality if not properly maintained. If the filter within your system is full of pollutants, this can make it more difficult to properly filter and distribute cleaner air into your indoor space. Change filters regularly in order to continue function of your ventilation or air cleaner technology.

Other Tips to Combat Poor Indoor Air Quality

  • To avoid excess exhaust, do not idle automobiles inside the garage.
  • Use cleaning, household and hobby products that are less toxic.
  • Do not store any hazardous products or chemicals inside.