Indoor Air Pollution: Health Effects & How to Improve Air Quality

Indoor air pollution can come from many sources, including smoke, combustion appliances, dust, mould, cleaning products and other chemicals released inside the home. The health risk depends on the pollutant, its concentration, how long you are exposed and your individual health.

Quick Answer: What Is Indoor Air Pollution?

Indoor air pollution occurs when chemical, physical or biological contaminants affect the air inside a building. Some pollutants can irritate the eyes, nose, throat and lungs. Long-term exposure to certain forms of air pollution can contribute to serious respiratory and cardiovascular disease.

The important point is that indoor air quality is not determined by one product or one toxin. Ventilation, moisture, combustion, smoking, building materials, cleaning products and outdoor air entering the home can all play a role.

What causes indoor air pollution?

Sources vary from home to home. Common contributors can include:

• tobacco smoke and other forms of indoor smoke
• gas, wood or other combustion appliances
• fine particles from cooking and burning
• mould and excess moisture
• dust and allergens
• volatile organic compounds released by some paints, furnishings and household products
• cleaning sprays and fragranced products
• outdoor pollution that enters through doors, windows and ventilation systems

WHO identifies particulate matter, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide among pollutants of major public-health concern. The sources and concentrations found in an individual Australian home can differ considerably from the severe household smoke exposures seen in parts of the world where solid fuels or kerosene are used for cooking and heating.

Can indoor air pollution affect your health?

Yes. Air pollution can affect both respiratory and cardiovascular health. The World Health Organization links exposure to air pollution with conditions including chronic obstructive pulmonary disease, heart disease, stroke, lung cancer and respiratory infections.

That does not mean every headache, cough or episode of fatigue is caused by the air in your home. Symptoms have many possible causes. If symptoms persist, become severe or concern you, seek appropriate medical assessment rather than assuming indoor air is responsible.

What symptoms can poor indoor air quality cause?

Depending on the pollutant and level of exposure, short-term effects can include:

• irritated or burning eyes
• nose or throat irritation
• coughing
• headache
• breathing discomfort

People with asthma or other respiratory conditions may be more sensitive to some airborne pollutants. Symptoms alone cannot identify a specific indoor pollutant, so recurrent problems may require investigation of both the environment and the person’s health.

Why does ventilation matter?

Ventilation brings outside air into an indoor space and helps dilute and disperse smaller airborne particles. Victorian Department of Health guidance notes that ventilation can improve overall air quality and can be provided naturally or mechanically. Filtration can also supplement ventilation in appropriate settings.

A tightly closed home is not automatically unhealthy, and opening windows is not appropriate in every situation. For example, outdoor smoke, pollen or poor outdoor air quality may sometimes make natural ventilation less desirable. The best approach depends on conditions inside and outside the home.

Does cooking affect indoor air quality?

Cooking can generate particles and gases, particularly when food or fuel is burned. Combustion appliances can also contribute pollutants. Using an effective rangehood that vents outdoors, maintaining appliances and avoiding unnecessary smoke can help reduce indoor exposure.

If you use a fuel-burning appliance, follow the manufacturer’s maintenance and ventilation requirements. Carbon monoxide is colourless and odourless, so suspected exposure requires urgent attention rather than relying on smell.

What about mould and dampness?

Persistent moisture can encourage mould growth. Rather than simply masking a musty smell, look for the source of moisture, such as leaks, condensation or inadequate ventilation. Fixing the moisture problem is an important part of controlling recurrent mould.

Do cleaning products and fragrances pollute indoor air?

Some household products release volatile chemicals or aerosols into the air. This does not mean every conventional cleaning or personal-care product is dangerous. Exposure depends on the ingredients, amount used, ventilation and how the product is applied.

A practical approach is to use products as directed, avoid unnecessary mixing of chemicals, provide ventilation where appropriate and reduce heavily fragranced or aerosolised products if they trigger irritation.

Can air purifiers improve indoor air quality?

Air cleaning and filtration can be useful for some airborne particles, but an air purifier is not a solution for every indoor-air problem. Source control and appropriate ventilation remain important. The right filtration system depends on what you are trying to remove, the size of the room and the device’s specifications.

An air purifier also cannot fix a gas leak, carbon monoxide problem or ongoing moisture source.

How can you improve the air quality in your home?

Start with the sources you can control. Keep the home smoke-free, maintain fuel-burning and ventilation equipment, use kitchen and bathroom exhaust systems appropriately, address water leaks and persistent dampness, and reduce unnecessary sources of smoke or airborne chemicals.

Ventilation can help dilute airborne contaminants when outdoor conditions are suitable. Filtration may provide additional benefit for particles in some homes, but it works best as part of a broader indoor-air strategy rather than as a substitute for removing the source.

“When someone is worried about their home environment, I prefer to look at the likely sources and practical changes rather than assume every symptom is caused by a hidden toxin.” — Mick Jordan

When should you seek professional advice?

Seek medical advice if you have persistent breathing problems, wheezing, recurrent respiratory symptoms or other unexplained symptoms. Severe breathing difficulty, confusion, collapse or suspected carbon monoxide exposure requires urgent medical attention.

If several people develop similar symptoms in the same building, or symptoms repeatedly improve when you leave, it may also be appropriate to investigate the building environment.

Frequently Asked Questions About Indoor Air Pollution

Is indoor air always more polluted than outdoor air?

No. Indoor and outdoor pollution levels vary with the building, location, weather, ventilation and pollution sources. Claims that indoor air is always a fixed number of times more polluted than outdoor air oversimplify the issue.

Can poor indoor air quality cause headaches?

Some pollutants can be associated with headache or irritation, but headaches have many possible causes. Persistent or severe headaches should not automatically be attributed to indoor air quality.

Does opening windows improve indoor air quality?

It can. Natural ventilation may help dilute indoor pollutants when outdoor air quality is suitable. During bushfire smoke, heavy traffic pollution or other periods of poor outdoor air, opening windows may not be the best option.

Do I need an air purifier?

Not necessarily. Filtration can help with some airborne particles, but first identify and reduce the source where possible. Ventilation, moisture control and appliance maintenance may be more important depending on the problem.

Can indoor air pollution affect asthma?

Yes. Some airborne pollutants and allergens can aggravate respiratory symptoms in susceptible people, including people with asthma. Individual triggers vary.

A practical approach to healthier indoor air

You do not need to make your home chemically sterile. Focus on sensible measures: reduce smoke and unnecessary emissions, control moisture, maintain appliances, ventilate appropriately and investigate persistent problems rather than relying on alarming claims about everyday household products.

For authoritative information, see the World Health Organization information on air pollution and Victorian Department of Health guidance on ventilation.

About Mick Jordan

Mick Jordan is a naturopath and Sports and Remedial Massage Therapist based in Brighton, Melbourne, with more than 30 years’ experience in natural therapies. He has a particular interest in nutrition, digestive health, sports performance and recovery, and takes an individual approach to helping clients improve their health and wellbeing.

Disclaimer: This article provides general health information and is not a substitute for individual medical advice. If you have persistent respiratory symptoms, asthma, suspected carbon monoxide exposure or another health concern, seek advice from an appropriately qualified health professional.