The effects of long-term carbon monoxide (CO) exposure are wide-ranging. Tissue damage occurs at levels much lower that those required to trigger a domestic CO alarm (Penney, D., Benignus, D. (2010)), with the brain and heart being particularly vulnerable (Sungho, Sang-Cheon 2016, Suner, Jay 2008). Psychiatric disease can also result.

A number of studies have shown that CO levels within the passenger cabins of cars approach, and in some cases exceed, WHO limits (Potcher, Oz et al 2014, Duci, Chaloulakou et al, 2003). Comparison of in-car CO values and ambient CO, as measured by environmental stations, 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. The public health implications of this are clear. In the UK, approximately 16.7m people commute to work by car (source: RAC Foundation). If CO leaks are present in even a small percentage of these vehicles, the potential scale of CO exposure is very high.

Given that young children are especially well-represented in the population of those who travel daily in cars, this is especially concerning.

Since testing began in February 2018, tests have shown that in Q1 (n=8) 25% of cars, and in Q2 (n=5) 60% of cars contained significantly elevated CO levels. Our highest peak measured level so far has been 1,100 ppm. While these results are concerning, the sample size is small.

There is a need to compile data on the issue using a good-quality UK-based sample size (>100). Southern Gas Networks has kindly volunteered to supply 30 test vehicles each from leased fleet, staff private cars and SGN vans.

With data generated from a three-way pilot-sample of this size, it will be possible to extrapolate sufficient information to plan wider tests of UK-wide, in-car CO exposure. Data from such tests will, in turn, bring focus to the issue at policy level across a range of bodies, including Public Health England, DEFRA, and the Royal College of GPs.

This study draws on established clinical literature to test the theory – never before examined in the UK on a wide scale – that a significant proportion of cars may be exposing their occupants to unsafe levels of CO.

Run by a Lead Researcher qualified in both medicine and law, this project uses cost-efficient technology. The findings of this project could lead to far-reaching change both in public policy and private car use.

On 28th April 2022, Dr Sophie Duggan presented the findings of the preliminary study for one the the Trust's Lecture Series. Her full presentation can be seen below.

Project in progress