What Gases Cause Indoor Air Pollution

What Gases Cause Indoor Air Pollution & How To Prevent It?

It’s not news that gases polluting the air we breathe, even in minute quantities, can have a huge effect on the health and wellbeing of building occupants. Worryingly, many of the most dangerous gases found inside buildings have no smell or colour, and so often the first indication that there might be a problem with indoor air pollution is staff members complaining of headaches, nausea or a general feeling of being unwell.

In the UK, all businesses and commercial operations, the employer has a responsibility under Health and Safety legislation to make sure that dangerous gases aren’t getting into areas where people are working. If there is a potential risk of this happening they must take reasonable precautions to manage this type of exposure to safe levels. Employers can only do this if they understand the risks and what gases may be polluting the atmosphere.

What types of gases can cause common indoor air pollution problems?

Every office, factory, school, hotel or hospital is different, and just because staff have started to complain of headaches or a “funny smell”, don’t automatically jump to the conclusion that noxious gases are to blame. The most common gases which can cause air pollution issues reducing air quality in both commercial and residential properties are:

Carbon monoxide

Carbon monoxide is a gas known as the silent killer as over exposure to fumes can be lethal. Carbon monoxide is most commonly associated with the incomplete combustion of fossil fuels (coal, wood, charcoal, gas), and is often linked to faulty boilers, gas fires, BBQ’s or solid wood stoves. To reduce the risks always make sure appliances are serviced regularly by competent engineers, and invest in a couple of carbon monoxide alarms which will alert you immediately to any rising levels of the gas at home or work.

Carbon dioxide

Carbon dioxide is one of the gases that we breathe out. It’s not deadly, but too much carbon dioxide in the air can lead to people complaining of headaches, or a feeling that a room is “stuffy”. It’s particularly a problem in poorly ventilated spaces with no fresh air coming in from outside, and where workers are tightly packed together.


Radon is a gas which occurs naturally and although usually found at low levels outdoors, it can build up to dangerous levels indoors. High levels of radon and prolonged exposure to the gas can increase risks of developing lung cancer. Some areas of the UK are affected by radon more than others, and there are maps on the UK Radon website to help you evaluate the risk. Areas of the UK at high risk include Devon, Cornwall, Wales and parts of Northern Ireland.

Volatile Organic Compounds (VOCs)

VOCs are chemicals found in many different commonly available chemical products such as solvents, paints, paint stripper and other cleaning products. Whether VOCs are an issue in your organisation will depend on your business; it’s probably something you should be thinking about if you run a dry cleaners, car body spraying business or are using large quantities of solvents.


Formaldehyde is one of the few gases which does have a very distinctive smell. It’s commonly used in the manufacture of building products, and so if you or your neighbour is having building work done, it can cause short term problems. If you are using formaldehyde at work in your own production processes, you should have procedures in place to minimise risk.

How can gas sensors help reduce air pollution?

As most of the gases which can cause indoor air pollution problems in the workplace have no scent or colour, specialist gas analysis equipment is usually needed to test for their presence. This gas testing can be done in a variety of ways.

Carbon monoxide alarms are a good example of a gas sensor which has been developed to continuously monitor levels of that one particular gas in the environment, and sound an alarm if levels reach a specified limit. Similar sensors and alarms are available to detect levels of methane, natural gas or carbon dioxide.

Sometimes, installing these gas sensors is a legal requirement. Residential landlords, for example, must by law install carbon monoxide detectors in any living accommodation where there is a solid fuel burner.

Other gases and particles in the air cannot be detected by using a sensor, and with so many different gases causing issues at different times, it would be impossible to install detectors for every possible eventuality.

Using gas testing equipment

If you have already installed gas detectors in your home or commercial property but still want to test for other gases in the air, you’ll need to use specialist gas testing equipment. Companies such as WTS which test for gas pollutants in indoor environments use equipment which literally sucks the air in to a specialist analyser, passing through a filter at a given rate over a set period of time. The equipment will then be used to analyse this known volume of air to determine what gases are present and at what concentrations. Results are provided in a report with graphs, highlighting any potential issues which are found. This testing might be done on a one-off basis, or repeated regularly, depending on the nature of the business, levels or sources of contamination.

Taking steps to reduce gas pollution levels and improve air quality

Once you have the report indicating what gases – if any – are polluting your air, then the next step is to work out what you can do to resolve the problem. Sometimes it might be a very “quick fix” solution such as adding in an extractor fan, additional window or vents to improve ventilation and allow more circulating fresh air into the space affected.

If the air quality issues are more complex, you might need to look into more radical solutions such as an air conditioning or local exhaust ventilation (LEV) system with filters and ducts to channel fresh air into the workspace and to extract the unwanted gases to the outside. As the composition of air varies hugely, so do the ways of fixing problems and making your air safe to breathe, clean and fresh.

Specialist air quality monitoring & testing solutions

Water Treatment Services offer a comprehensive range of indoor air testing, gas monitoring and environmental evaluation solutions. Find out and how we can help improve workplace health and well-being, employee comfort, attendance and productivity issues. We can provide advice and full support to help you identify the most appropriate strategies for managing your indoor air quality issues.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained engineers, air quality specialists and technicians we offer cost effective air testing and environmental support solutions across the whole of the UK and Ireland.


Further reading…

More information about sick building syndrome … here →

What Gases Cause Indoor Air Pollution & How To Prevent It?
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What Gases Cause Indoor Air Pollution & How To Prevent It?
Learn more about what gases cause indoor air pollution and how to prevent it. What are the most common gases which can cause air pollution issues reducing air quality in both commercial and residential properties.
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Water Treatment Services
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