The Dangers of Contaminants in Compressed Breathing Air

by | May 15, 2020 | Personal Safety

All employers have a duty of care to their employees to ensure that breathing air is safe to breathe. If you think for a moment that testing contaminants in compressed breathing air is a hassle, then think again.

Why is Testing Important?

People who work in environments with poor air quality are often supplied with a respiratory mask. These areas include fire fighting, scuba, paint spraying and confined spaces. When people wear a respiratory device, they’re usually relying on it as their primary source of air. Poor air quality can pose a significant health risk, and even death in the worst-case scenario.

Testing of breathing air is regulated by BS EN12021:2014 for good reason. If you follow the guidelines set by EN12021, the recommendation for breathing air testing is to be carried out every 3 months.

Contaminants in Compressed Breathing Air

Breathing air is usually supplied by an air compressor via an airline or by a pre-filled cylinder. There are various reasons why contaminants can become a problem within the airline.

We look at the five most common contaminants found in compressed breathing air.


1. Water Vapour

Before air leaves a compressor, it is cooled which leads to water vapour condensation. As a result, water vapour can be found throughout your breathing air system.

Water vapour in compressed breathing air can be problematic for a variety of reasons. If the water vapour condenses into liquid, it can then freeze in cold weather, creating a potentially dangerous blockage of airflow. High water content can also increase the risk of exposure to other contaminants, like corrosive particulates.


2. Carbon Monoxide

Carbon Monoxide (CO) in compressed air mostly comes from either the compressor or the compressor’s air intake.

Carbon Monoxide is dangerous because it competes with oxygen in hemoglobin cells found in your blood. It can cause symptoms such as disorientation and loss of consciousness.

Strenuous activity will cause a person to take in larger amounts of contaminated air. Firefighters and scuba divers already face dangerous situations and must be particularly aware of the dangers that CO presents. At high enough concentrations it can kill in less than an hour.


3. Carbon Dioxide

Carbon Dioxide (CO2) is a toxic gas. With its odourless, tasteless, and colourless properties, it poses a greater threat to the body’s natural defence mechanisms. Being unable to smell, taste or see it, heightens the dependence on regular testing in breathing air applications.

The exact symptoms of CO2 poisoning depend on the level of concentration in the air. Once CO2 is inhaled, at dangerous levels it disables the blood’s ability to move oxygen to the heart and brain. At just 2% (20,000ppm), it causes dizziness, headaches, an increased heart-rate or hearing impairments. At 5%-10%, more severe symptoms include confusion, tiredness, loss of breath, and eventually unconsciousness.

CO2 contaminants in compressed breathing air may derive from a few different sources. It’s important to take a look at the air compressor. CO can contaminate a compressor’s intake air for a variety of reasons. If positioned outside, if the compressor is in an area near vehicles that are running and emitting exhaust, this could contribute to the intake of CO2.


4. Oxygen

It’s important to monitor your oxygen levels to ensure you’re not breathing in an inadequate or excessive amount. The EN12021 standards for breathing air state oxygen must be in the range of (21% +/- 1%).

The minimum oxygen concentration in the air required for human breathing is 19.5%.

Between 19.5% and about 12%, you’re likely to suffer from impaired judgement and poor coordination. 10%-12% is likely to cause sickness, tiredness and dizziness. Low concentrations will result in unconsciousness, heart attack and ultimately death.


5. Oil Mist

Lastly, but just as important, atmospheric air typically contains between 0.05 mg/m3 and 0.5mg/m3 of oil mist. As oil is comprised not only of liquid and aerosol, but also vapour, the common sources are vehicle or motor exhaust and industrial processes such as solvents used to clean piping and threads and glue used to cement connections.

Potential symptoms of exposure to high concentrations of oil mist include eye irritation, shortness of breath, nausea, fever, rapid heartbeat and a burning sensation in the mouth, throat and stomach.


If you require guidance on the contaminants in compressed breathing air or information surrounding the testing that required, contact a1-cbiss. We supply the AIRQUAL-1  – a breathing air quality test kit for testing cylinders, air lines and your compressor for contaminants.