Indoor air quality (IAQ) is the air quality inside and near buildings, including the air in your home. A growing body of research has discovered the relationship between air quality and human health, finding that poor IAQ can negatively impact health and wellbeing in a variety of ways.

Air quality is a major threat to public health. According to the State of the Air Report, air quality in the United States has improved, but more than 40% of the population lives with an unhealthy level of air pollution. Further, other studies have found that global air pollution is increasing, suggesting that poor air quality will continue to be an issue for years to come.

While you may not be able to control outdoor air quality, you can control IAQ in your home. To protect your and your family’s health, it’s vital to do what you can to improve your IAQ.

Causes of Poor Indoor Air Quality

There are many causes of and contributors to poor IAQ, including:

  • Biological pollutants, including bacteria, fungi, mold, spores, mites, dust, pollen, pet dander and waste, and other microbes;
  • Excess moisture;
  • Sewage and low-quality water;
  • Volatile organic compounds (VOCs), which can be found in many cleaning products, construction materials, hobby supplies, and other commercial products;
  • Pesticides;
  • Smoke from residential wood fires, wildfires, and volcanic eruptions or activity;
  • Radon;
  • Asbestos, which can be found in older homes;
  • The six criteria of air pollutants, which include carbon monoxide, nitrogen dioxide, ozone, lead, sulfur dioxide, and particulate matter;
  • Exhaust from cars and other vehicles;
  • Second- and third-hand inhalant smoke, including tobacco and marijuana smoke;
  • Contaminated HVAC systems and filters;
  • Factories and other industrial activities.

There is no single or even primary source of air pollution. The concentration of each contaminant also varies based on location. For instance, if you live close to a freeway, you’re more likely to be exposed to vehicle exhaust; if you live in a rural, agricultural area, you’re more likely to be exposed to pesticides.

Health Effects of Poor Indoor Air Quality

There is a strong link between air quality and human health. You breathe an average of 12 to 20 times per minute, meaning you take just under 1,000 breaths per hour and over 20,000 breaths per day. With such constant exposure, it’s impossible to not be affected by the air you breathe.

The exact health impacts of poor air quality differ from person to person. The duration of exposure, type of pollutants, and concentration of each contaminant in the air all influence how air quality can affect health. Further, your health condition and history may also play a role in how air quality affects you.

Physical Health

Poor IAQ can have almost immediate impacts on your health. Some short-term symptoms of exposure include:

  • Eyes, throat, and/or nose irritation;
  • Headaches;
  • Dizziness;
  • Stomach aches or nausea;
  • Fatigue;
  • Confusion;
  • Allergies;
  • Coughing or sneezing;
  • Congestion.

Many of these symptoms overlap with respiratory illnesses, such as the common cold, making it difficult to pinpoint the exact source. If the symptoms subside once you start breathing cleaner air, then low-quality air was likely the culprit.

There are also several severe long-term health effects of breathing low-quality air:

  • Respiratory disease, including reduced lung function;
  • Cardiovascular disease, including heart attacks and stroke;
  • Cancer;
  • Damage to the nervous system;
  • Premature death.

Generally, the more exposure you’ve had to poor quality air, the more likely you are to develop long-term health problems because of it.

Mental Health

In addition to its impacts on your physical health, poor air quality can also affect your cognitive and mental health. Air pollution has been linked to the following mental health issues in adults:

Air pollution is also thought to have serious effects on children’s mental health and cognitive development. Childhood exposure to low-quality air can contribute to mental health issues in adulthood. Even short-term exposure has been linked to increased anxiety, depression, and suicidal ideation and attempts in children.

Who Is Most at Risk of Health Complications?

Poor indoor and outdoor air quality is dangerous for everyone, but certain groups are at an even greater risk of experiencing health complications:

  • Infants and children;
  • Seniors;
  • Animals and pets;
  • People who smoke;
  • Individuals with pre-existing health conditions, particularly those that impact the respiratory system;
  • Pregnant people;
  • People who work outdoors;
  • People who exercise or are physically active outdoors.

Some communities — particularly low-income communities made up of people of color — are disproportionately exposed to low-quality air, which increases the chance of experiencing related health problems. The reasons for these disparities are complex and deeply rooted, but likely have to do with a combination of social and environmental factors.

Indicators of Poor Indoor Air Quality

To avoid the health consequences of air pollution, look out for the following indicators of poor air quality in your home:

  • Inconsistent air distribution in your home (such as pockets of cold or warm air);
  • Visible dust buildup, particularly around vents and ducts;
  • Humidity issues, especially if humidity is above 50%;
  • Strange or unpleasant smells;
  • Visible mold or mildew growth;
  • Experiencing short-term health effects, especially if the symptoms are new, worsening, or only present when in your home.

If you notice these signs in your home, it doesn’t automatically mean you have poor air quality; there may be another, unrelated cause. However, if you find multiple signs in your home, it’s worth getting your air tested professionally, as this is the best way to determine its quality. At-home test kits are available, but they aren’t always accurate. In addition to a general air quality test, you should also consider testing your home for specific pollutants, including radon, mold, asbestos, and lead.

How to Improve Indoor Air Quality

Luckily, you can take steps to improve your IAQ. This may involve some trial and error, but there are multiple strategies you can try as you figure out what works best for your home.

Cleaning

Properly cleaning and maintaining your home is an essential first step in improving your air quality.

First and foremost, you should dust and vacuum your home frequently to get rid of dust, pests, pet dander, and other pollutants. You should also focus your cleaning efforts on areas that are more likely to reduce air quality, particularly the kitchen and bathrooms.

Avoid using harsh chemicals when cleaning your home, and opt for gentler, natural alternatives. Be careful, however, as some green cleaners are still hazardous when used incorrectly.

In addition, be sure to clean your HVAC system. This includes regularly cleaning your air ducts and replacing your air filters.

Upgrades

Air quality is dependent upon the inner workings of your home. Your HVAC system and plumbing system directly affect the quality of your air, and if these systems aren’t working properly, you will likely have to replace or upgrade them to truly improve your air quality.

Depending on the type of pollution you’re dealing with, you may have to fix up, install, or replace:

  • Air conditioning filters;
  • Air ducts;
  • Exhaust fans;
  • Leaky pipes;
  • Kitchen appliances, including your stove or oven;
  • Sewer lines;
  • A humidifier.

These changes can be costly, but it’s always best to fix the root cause of your poor air quality. If you just focus on the side effects, then the issue will persist and continue to jeopardize your health.

For instance, if your kitchen stove is leaking carbon monoxide, an air filter or purifier may help, but at the end of the day, your stove is still polluting your air. It’s significantly better to remove the pollutant itself, rather than continually address its side effects. It’s far safer for your health to take this kind of approach, especially since you’ll likely have to deal with that root cause in the future.

Additional Measures

There are additional measures you can take to boost the quality of your air:

  • Purify your air;
  • Open doors and windows when outdoor air quality is good;
  • Close doors and windows when outdoor air quality is poor;
  • Increase ventilation throughout your home, including for your plumbing and HVAC system;
  • Avoid harsh cleaners, paints, pesticides, or other household products that contain pollutants;
  • Find the right level of humidity for your home;
  • Place air-purifying plants in your home;
  • Use air fresheners, candles, incense, and essential oils sparingly, especially if they artificially scented;
  • Run bathroom exhaust fans to reduce the chance of mold growth;
  • Don’t smoke indoors;
  • Pay attention to your local air quality by checking the Air Quality Index.

You can do your part to reduce your contributions to outdoor air pollution by reducing your carbon footprint. This includes picking a cleaner mode of transportation (such as a bike or public transit) instead of your car and conserving power and gas as much as possible.

Many of these solutions are relatively easy to implement; you just need to make some small shifts to your habits and routine. When it comes to air quality, a little goes a long way.