Top 7 Common Causes of Bad Air Quality


It can be difficult to check whether or not the air inside your home is contaminated by merely observing. However, it is crucial to maintain good indoor air quality to ensure the health of everyone living in the space and breathing the same indoor air. 

Several factors can affect the quality of the indoor air in your home. An indoor air quality monitor is the easiest method to determine if your house has bad air quality. 

What Causes Bad Air Quality?

No matter how often you clean, or if you have the most advanced appliances in your home, pollutants are bound to enter its premises. It is crucial to know what causes the problem and how you can prevent them before anyone in your household gets sick from breathing polluted air.

Here’s a look at the common causes of bad indoor air quality:

Poor ventilation

Poor ventilation is the number one cause of bad air quality, not only when it comes to pollutants but also humidity. If your home has high humidity, you’ll notice a musty smell, mildew on the walls and floors, and water condensation forming on windows and other surfaces. Allowing proper airflow to let the moisture out of your home will help clean the air.

Another thing to consider is that air cleaners are only part of the solution for keeping your home’s air healthy. They’re not the complete answer or replacement for having good ventilation in your home. 

Properly filtering your home’s air means taking multiple approaches simultaneously, and keeping everything in balance can make all the difference.


Mold is another one of the more common problems that can affect indoor air quality. It’s usually caused by moisture, releasing tiny spores into the air. These spores can trigger respiratory issues and allergic reactions in those sensitive to them. 

People who have asthma or other preexisting lung conditions are typically more prone to experiencing symptoms from mold exposure because their lungs are already vulnerable to irritation.

Mold is most commonly an issue in areas prone to moisture buildups, such as bathrooms or laundry rooms. If you have a water leak somewhere in your home or live in a place where humidity is high, mold growth can be likely, especially if left untreated for long periods. 

To remove mold from your home, use plain bleach diluted with water. This should be sprayed on any affected areas and allowed to sit undisturbed for at least 15 minutes before being wiped down with clean towels.

Pollen and pet dander

Itching and sneezing, irritated eyes and throat, wheezing, coughing, and reduced lung functions are the common symptoms of seasonal allergies. Seasonal allergens such as pollen or pet dander can cause lung irritation or asthma attacks in susceptible individuals. 

Allergy symptoms can be reduced by frequent vacuuming with a HEPA filter vacuum cleaner to remove allergens from carpets, upholstery, or curtains. An air purifier is also helpful for eliminating these allergens from the air. Keeping pets out of sleeping areas may also be beneficial in reducing exposure to pet dander.

Caulk, paint, and other chemicals

Another common cause of toxins in your home is volatile organic compounds (VOCs), typically occurring when painting or redecorating. They can also happen due to sealing cracks and gaps throughout your home or off-gassing from new furniture.

VOCs can come from the chemicals in cleaning products. While keeping a clean living space is important, it is equally important to avoid using harsh cleaners containing VOCs and opt for natural alternatives. When using cleaners with potentially hazardous chemicals, make sure to ventilate your space by opening windows and doors.

Radon gas

Radon gas is a colorless and odorless radioactive gas that can cause respiratory illnesses. It originates from the normal decay of uranium in rock, water, and soil. It is present in many parts of the US at varying levels. 

High levels of radon have been found in homes all over the country, which no one could predict. It depends on local geology, construction materials, and how well your home is sealed.

Radon gas enters homes through cracks in foundation walls or floors, gaps in construction joints, and cavities inside walls. The easiest way to test for the existence of radon is with a do-it-yourself kit that you can purchase at a hardware store or online at around $40 to $50. 

Take readings for two days following the test kit instructions, mail in the results of those readings, and get your answer within two weeks.

Secondhand smoke

If you’re not a smoker yourself, you can still be at risk of breathing in secondhand smoke. This harmful smoke can cause cancer and lung disease. It also causes irritation to the eyes and throat.

In addition, since passive smoking is more difficult for non-smokers to avoid than active smoking, people exposed to cigarette smoke are less likely to have control over their environment and health. 

Children, non-smoking pregnant women, and pets are more likely to suffer from secondhand smoke because they cannot control where they spend most of their time.

Suppose you live with a smoker who refuses or cannot quit, ask them to step outside the house when smoking. You can also opt to install an HVAC system to make the indoor air cleaner.

Incense, candles, and fireplace emissions

Burning incense, scented candles, and wood-burning fireplaces are popular for their pleasant aromas and the relaxed feelings they induce. But without proper ventilation, however, they can also be significant contributors to poor indoor air quality and some of its associated health issues.

The American Lung Association confirms that burning incense and scented candles releases fine particles that can create smoke and also provoke asthma symptoms. 

The Bottom Line

Bad air quality is certainly an issue, but there are ways to reduce your home’s pollution. The three leading causes of poor air quality in most households are dust, mold, and pet dander. The best measure to reduce these factors is investing in a good HVAC system.