According to a study published in the European Journal of Preventive Cardiology, smoking while donning a surgical mask increases carbon monoxide breathed by a factor of two.
Traditional (combustible) cigarettes and non-combustible cigarettes were the subjects of the study (containing tobacco that is electronically heated).
E-cigarettes, which electronically heat a nicotine-containing liquid, were not included.
40 smokers of conventional cigarettes, 40 users of non-combustible cigarettes, and 40 non-smokers participated in the study.
The levels of carbon monoxide smokers inhaled during working hours while wearing a mask and during non-working days were examined by the researchers.
Exhaled carbon monoxide rose in smokers of conventional cigarettes from 8.00 parts per million (baseline) to 12.15 parts per million with no mask and 17.45 parts per million with a mask.