Inhaled CO2 concentration while wearing face masks: a pilot study using capnography


None of the available evaluations of the inhaled air carbon dioxide (CO2) concentration, while wearing face masks, used professional, real-time capnography with water-removal tubing. We measured the end-tidal CO2 using professional side-stream capnography, with water-removing tubing (Rad-97™ capnograph), at rest, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator, in 102 healthy volunteers aged 10-90 years, from the general population of Ferrara province, Italy. The inhaled air CO2 concentration was then computed as: ((mask volume × end-tidal CO2) + ((tidal volume – mask volume) × ambient air CO2)) / tidal volume).

The mean CO2 concentration was 4965±1047 ppm with surgical masks, and 9396±2254 ppm with FFP2 respirators. The proportion of the sample showing a CO2 concentration higher than the 5000 ppm acceptable exposure threshold recommended for workers was 40.2% while wearing surgical masks and 99.0% while wearing FFP2 respirators

The mean blood oxygen saturation remained >96%, and the mean end-tidal CO2 <33 mmHg. Adjusting for age, gender, BMI, and smoking, the inhaled air CO2 concentration significantly increased with increasing respiratory rate (with a mean of 10,143±2782 ppm among the participants taking 18 or more breaths per minute, while wearing FFP2 respirators), and was higher among the minors, who showed a mean CO2 concentration of 12,847±2898 ppm, while wearing FFP2 respirators. If these results will be confirmed, the current guidelines on mask-wearing could be updated to integrate recommendations for slow breathing and a more targeted use when contagion risk is low.  Video Here  (Approx. 13 Min)


The mask insanity may have reached its peak this week when unmasked stage actress, Patti LuPone, unleashed a tirade on an audience member for letting her mask slide below her nose, despite the lack of studies from the CDC proving mask efficacy against the spread of Covid-19. In fact, a new study out of Italy concluded that wearing a mask increases levels of inhaled CO2.

A study called “Correlation Between Mask Compliance & COVID-19 Outcomes in Europe found:

  • masks were unable to reduce COVID transmission 
  • countries with high levels of mask usage did not perform better than those with low usage
  • there was moderate positive correlation between mask usage and DEATHS

For more:

What nobody is touching with a 10-foot-pole is the 80 fold increase in mask-littering due to mask mandates and the impact on animal life as well as the environment.  But none of that matters in the topsy-turvy world of COVID.
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