Journal of Smoking Cessation


Pilot Study of the Use of Personal Carbon Monoxide Monitoring to Achieve Radical Smoking Reduction

Emma Bearda1 c1 and Robert Westa1

a1 Cancer Research UK Health Behaviour Research Centre, University College London, UK


Background and aims: This study examined whether providing smokers with a personal monitor for measuring expired-air carbon monoxide (CO) concentrations would be a feasible method of achieving a reduction in smoke intake. Methods: Ten smokers were given a CO monitor and asked to use it regularly throughout the day for 6 weeks with the aim of maintaining their CO reading below 10 ppm. They were advised to use nicotine replacement therapy, but this was not provided. At baseline and follow-up, smokers were asked to comment on their use of the monitors and motivation to stop smoking. Demographic characteristics, cigarette consumption, and nicotine dependence, was also assessed. Additionally, during the first 2 weeks participants were instructed to record how often they used their CO monitor, their average readings and cigarette consumption. Results: Eight smokers had an average daily CO concentration below their baseline on at least 93% of the days in the 2 weeks of daily monitoring, while three had CO levels below 10 ppm on 36% of the days. At the 6-week follow-up, all participants’ CO concentrations were below their baseline value; two were below 10 ppm. Average daily cigarette consumption reduced from 14.1 (SD 6.03) at baseline to 9.8 (SD 4.95) during the 2 weeks of daily CO monitoring (t = 2.46, df 9, p = 0.036) and 9.5 (SD 5.50) at 6 weeks follow-up (t = 1.73, df 7, p = 0.127). Use of the CO monitors was generally found to be acceptable and to increase motivation to stop smoking completely. Five smokers attempted to quit smoking. Conclusions: Regular personal CO monitoring may be a useful method for reducing smokers’ cigarette intake and increasing their motivation to stop completely. A controlled trial with long-term follow up is warranted.


  • smoking reduction;
  • NRT;
  • carbon monoxide;
  • self-monitoring


c1 Address for correspondence: Emma Beard, Cancer Research UK Health Behaviour Research Centre, University College London, WC1E 6BP. E-mail: