Complete guide to a healthy bathroom (air quality, moisture, and mold)

The bathroom can be a place to relax and freshen up but it can quickly become a health hazard when you ‘re not careful.

Common bathroom health hazards include mold growth, VOCs, and formaldehyde. These compounds can result in several negative health effects. You can prevent your exposure to them with good cleaning habits and the use of appliances such as an extractor fan or an air dehumidifier.

At the end of this post, you will find an overview table of all the common health hazards in the bathroom, their sources, and preventive measures.

Common health issues and air quality problems in the bathroom

The bathroom is often very moist and can, therefore, provide ideal circumstances for mold to grow. This can become an issue since mold spores can pose various health hazards.

Additionally, volatile organic compounds (VOCs) and Formaldehyde can cause air quality problems.

Mold growth

The spores of molds are always present in the air in very small quantities. They normally do not pose any health hazards. However, when mold spores land in a spot that is humid and warm, it can start to grow and produce very high quantities of spores. This can lead to various health effects and can damage wood and fixtures.

Since bathrooms are often very wet and the air generally has a very high relative humidity, mold growth is a common issue in bathrooms.

Negative health effects of mold

Bathroom mold growth can cause several health problems, mostly due to inhalation of high quantities of spores or contact with the skin. Health effects include (source):

  • irritation of eyes, nose, skin, lungs and throat
  • allergic reaction
  • asthmatic problems
  • respiratory ailments

Our own bathroom with a shower curtain showing a typical windmill and traditional dutch clothes and wooden shoes
Our bathroom with dutch shower curtain

Volatile organic compounds (VOCs)

The bathroom should be cleaned regularly and thoroughly. However, common household cleaning products release volatile organic compounds (VOCs) when used and stored. These compounds are mostly human-made chemicals that are emitted as a gas from solids or liquid. There are very many different volatile organic compounds and their effects can range from highly toxic to no known negative health effects.

The most common sources of VOCs in the bathroom are:

  • cleaning products
  • deodorizers
  • dry cleaning fluids
  • paint

Health effects of VOC exposure

Keep in mind that health effects depend on many factors such as level of exposure, duration of exposure, and the overall health of the person exposed.

Acute health effects of VOC exposure include:

  • headache, dizziness, loss of coordination, nausea, visual disorder
  • irritation of eyes and respiratory tract
  • allergic reactions including asthma and rhinitis

Chronic exposure to VOCs can lead to the following effects:

  • damage to kidney, liver, blood system, and central nervous system
  • some VOCs may cause cancer. (Formaldehyde)


Technically formaldehyde is a common VOC. However, I want to mention it separately because it is stated by the Environmental Protection Agency (EPA) to potentially cause cancer. It is a colorless, pungent-smelling gas and can be released from insulation and building materials such as composite wood. Other sources are:

  • cleaning products, fabric softeners and conditioners
  • carpeting
  • glues and resins
  • tobacco smoke
  • a type of insulation called urea-formaldehyde insulating foam UFFI)

Since formaldehyde is a VOC, its health effects are similar to the list above with the addition that there is some evidence that it might cause cancer.

Good bathroom habits to avoid exposure

To prevent and mitigate the effects of air pollutants and molds in your bathroom, there are a few good habits that you can adopt.

Properly ventilate the bathroom

Good ventilation is key for good air quality in every room of the house, and the bathroom is no exception. According to the EPA, indoor air quality is normally about five times worse than outdoor air. Therefore, ventilation should be happening constantly to provide fresh air and remove stale, polluted indoor air.

The bathroom especially requires good ventilation. A good exhaust fan is therefore highly recommended, especially if you are not able to open a bathroom window.

We do not, unfortunately, have an exhaust fan in our bathroom since we live in a rental apartment. Luckily, we do have blinds. This allows us to open the window while bathing or showering and simply have the blinds closed.

Don’t skip a good cleaning session

To prevent mold growth, proper cleaning is required. It is easy to do a general cleaning session and skip the important parts such as the grout lines between your bathroom tiles. However, in this way you allow mold growth to build up, making them harder to remove the next time. I would recommend wiping the grout lines with regularity.

Additionally, you should consider to dry the shower walls and tiles after you have taken a shower, This again prevents the potential for mold growth.

On top of that, the showerhead and faucets heads require a good clean as well.

Preventive measures

In order to prevent mold growth and bad air quality, ventilation is the most important. However, there are several other ways to make sure your bathroom is clean and healthy.

Preventing mold growth and exposure

There are several ways to prevent mold growth and exposure to its spores.

  • regular and thorough cleaning
  • continuous ventilation
  • installing an exhaust fan
  • installing an air dehumidifier
  • wear gloves, goggles and a mask when mold growth is extensive

How to prevent VOC exposure

Exposure to volatile organic compounds can be minimized by taking care of the following:

  • store cleaning agents according to the manufacturers instructions
  • unused or little-used containers need to be thrown away safely
  • never mix cleaning agents unless specified by the manufacturer
  • make sure to provide enough fresh air when using cleaning agents
  • use natural no-VOC cleaning agents
  • general: use low VOC paints in your house

Preventing formaldehyde exposure

Exposure to formaldehyde can be minimized by taking care of the following:

  • use formaldehyde-free or natural cleaning products
  • apply natural insulation and building materials
  • When using rugs, consider natural no-VOC options (I recommend

Additionally, according to the Environmental Protection Agency (EPA), the rate at which formaldehyde is released is increased by heat and may be affected by humidity. Therefore, maintaining moderate humidity and temperature levels can reduce exposure. The EPA advises air dehumidifiers to control indoor humidity. (source)

Appliances and anti-mold paint to improve bathroom health

Air dehumidifier

A dehumidifier is a device that takes up excess humidity from the air. Most dehumidifiers can be set to run for a certain time or to run until the desired humidity is reached.

There are many dehumidifiers in a wide price range and for many different areas such as the wardrobe, desktop, or bedroom. I studied some of the available dehumidifiers that are affordable and still provide for the needs of the bathroom where humidity levels are normally quite high.

Most dehumidifiers are designed as a small device for the bedroom or office to provide some comfort. But because of the relatively high humidity in the bathroom, you need a dehumidifier that is suitable for a larger space than the actual size of your bathroom.

Additionally, you will want a good water tank capacity so you do not have to empty the water tank all too often. Therefore I would recommend this dehumidifier, found on amazon.

Extractor fans

An extractor fan or exhaust fan makes sure the humid air in your bathroom is quickly transported outside. For the best functioning of your exhaust fan, inlet ventilation to replace the exhausted air is recommended.

There are two things to consider about a vent fan. One is the size and thereby the capacity to exhaust air. The second is the amount of noise that it makes.

The size and capacity of an exhaust fan is determined by the size of your bathroom. Generally, 1 CFM (cubic feet per minute) (0.1 square meters) is required per square foot (0.1 m2) of bathroom size. I would recommend being a bit generous on the CFM capacity.

The amount of noise that an exhaust fan produces might seem to not be worth much consideration. However, a relatively loud fan can easily discourage you from turning it on while you take a relaxing bath. Therefore I would highly recommend purchasing a low noise, or mute, exhaust fan.

Air quality monitors

To make sure you are always aware of the levels of humidity, VOCs, and other harmful substances in your bathroom, an air quality monitor is an excellent tool. Air quality monitors can measure airborne chemicals, temperature, and humidity, depending on the device.

I found a Norwegian company called airthings, that produces excellent air quality monitors. They are easy to operate (just wave your hand in front of the device) and send their data to an app on your phone.

Discount on Airthings air quality monitor

By using this link to the Airthings Wave Plus air quality monitor you will get a discount of about 10%!

This air quality monitor not only measures humidity levels and VOCs but also CO2 levels, temperature, air pressure, and radon.

Anti-mold paint

When we moved into our current apartment, there was mold all over the bathroom… So after a good cleaning session, we painted the walls and ceiling with anti-mold paint. We never had mold issues since then.

Things to consider while installing a bathroom

There are two things I want to mention if you are able to make major adjustments to your bathroom, for example when you are still installing the bathroom.

Insulation prevents condensation

Good insulation can prevent constant condensation to the walls of your bathroom. Because the walls can be relatively cold when scarcely insulated, airborne moisture that comes in contact with the wall will condensate more easily.

Larger tiles reduce grout lines and therefore are easier to keep clean

Grout lines in between your bathroom tiles are a hotspot for mold growth. Therefore I would recommend installing relatively large tiles. This reduces the amount of grout lines and makes the tiled wall much easier to clean.

Overview table

Table 1. overview of bathroom health hazards and preventive measures

Hazardous compoundsSourcesHealth effectsPreventive measures
Mold– mold spores are always present in the air
– mold growth increases spores
– irritation of eyes, nose, skin, lungs and throat
– allergic reaction
– asthmatic problems
– respiratory ailments
– regular and thorough cleaning
– continuous ventilation
– exhaust fan
– air dehumidifier
VOCs– cleaning products
– deodorizers
– dry cleaning fluids
– paint
– headache, dizziness, loss of coordination, – nausea, visual disorder
– irritation of eyes and respiratory tract
– allergic reactions
– use and store cleaning agents according to instructions
– never mix cleaning agents
– provide fresh air when cleaning
– use natural no-VOC cleaning agents
– general: use low VOC paints
Formaldehyde– cleaning products, fabric softeners and conditioners
– carpets
– glues and resins
– tobacco smoke
– UFFI insulation
– headache, dizziness, loss of coordination, nausea, visual disorder
– irritation of eyes and respiratory tract
– allergic reactions
– Formaldehyde potentially causes cancer
– use formaldehyde-free or natural cleaning products
– apply natural insulation and building materials
– consider natural no-VOC rugs