Recent studies have shown that the air inside cars can contain dangerous levels of carbon monoxide (CO). Carbon monoxide (CO) levels within the passenger cabins of cars approach, and in some cases exceed, WHO limits.

Driving on heavily-polluted roads exposes passengers to raised levels of CO through the air intake of the car. However, in-car CO exposure depends not just on the quality of air outside the car, but on the performance of systems within the car as well.

Comparison of in-car CO values and ambient CO indicates that this is likely to be due to internal leakage of exhaust gases, rather than to simple ingress of external pollution. To date, however, no comparable study has been published within the UK.

AirSafe London began investigating this issue in 2018, supported by the CO Research Trust and have carried out two phases of testing to date. The results so far are concerning. Of 26 cars tested, nine showed significantly elevated in-car CO levels.

The public health implications of this are significant, particularly for professionals such as gas safe engineers, who spend a considerable amount of time driving.

The goal of AirSafe London is to help protect passengers, and to achieve this, they need to test more vehicles, to obtain good-quality data.

AirSafe London are now looking to recruit companies who would be willing to put monitors into their cars, particularly those of professionals who spend a lot of time on the road.

Testing is very simple. A lightweight self-calibrating device plugs into an iPhone (Androids are not yet fully supported) that is inside a vehicle. The results are emailed using an app. Journey logs can be as short as five minutes, or longer if users prefer. The longer the recording time, the more data that can be collected. The testing will need to take place over a two-week period.

In vehicle testing kit
In vehicle testing kit

If you would like to take part in this crucial study to help contribute to reducing CO exposure, please email Dr Sophie Duggan at

The effects of long-term carbon monoxide (CO) exposure are wide-ranging and can be devastating. Your support in helping to eliminate the risk of CO poisoning is much appreciated.

Thanks in advance,

Dr Sophie Duggan, AirSafe London and Adrian McConnell, CO Research Trust.


About AirSafe London

AirSafe London is a project set up by Dr Sophie Duggan, after her own car exposed her family to toxic fumes in 2013. After attending meetings of the All-Party Parliamentary Carbon Monoxide Group, it became clear that in order to influence policy on in-car air quality, it would be necessary to produce clear evidence of the scale of the problem. The AirSafe study is Sophie’s response to this: an independent research project, conducted on a pro-bono basis, to demonstrate the likely extent of in-car CO exposure in the UK today.

About the CO Research Trust

The CO Research Trust (formerly the Gas Safety Trust) is a registered charity which was established in 2005. The vision of the charity is a world where people are not exposed to carbon monoxide (CO).

For more information please contact;

Natalie Fleck

CO Research Trust
Follow us: @COResearchTrust

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