Peer-reviewed article
Carbon dioxide rises beyond acceptable safety levels in children under nose and mouth covering: Results of an experimental measurement study in healthy children
Harald Walach, Helmut Traindl, Juliane Prentice, Ronald Weikl, Andreas Diemer et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This experimental study measured carbon dioxide levels in inhaled air when children aged 6-17 wore surgical masks or FFP2 masks. Researchers found CO2 levels rose to 13,100-13,900 ppm under masks compared to baseline levels around 2,700 ppm. The study was conducted in a controlled laboratory setting with 45 healthy children seated for short periods. The authors suggest these levels might be hazardous to children's health.
Key points
- CO2 levels under surgical masks averaged 13,100 ppm (SD 380); under FFP2 masks averaged 13,900 ppm (SD 370)
- Baseline CO2 levels were 2,700-2,800 ppm
- Study included 45 children (25 boys, 20 girls) with mean age 10.7 years
- Measurements were taken over 3 minutes per mask type in a seated, resting position
- Difference between mask types was small and not statistically significant
Limitations
This is a short-term laboratory measurement study under artificial conditions (seated, resting position) that does not assess actual health outcomes or physiological effects on children. The study does not measure whether measured CO2 levels cause harm, and findings from 25-minute controlled observations may not reflect real-world mask-wearing conditions, duration, or activity levels.
Abstract
Nose and mouth covering (NMC) has been made compulsory for children in many countries during the Covid-19 pandemic. We wanted to determine the average CO2 levels in inhaled air with NMC in children between age 6 and 17. We used short term measurements under surgical masks and FFP2 masks according to European norm EN 149, compared to baseline in an experimental, intra-individually controlled study over 25 min. CO2 content was measured every 15 s using an automated dual-wavelength infrared CO2 measurement device (G100, Geotech, Leamington Spa, UK) over 25 min in a short-term experimental setting, with children seated. After baseline measurement children were provided with two types of commonly worn NMC: surgical masks and FFP2--masks in randomized sequence for 3 min each. We kept ambient CO2-levels below 1000 parts per million (ppm) through frequent ventilation. We measured breathing frequency and pulse as potential physiological moderator variables. Forty-five children, 25 boys, 20 girls, with a mean age of 10.7 years (standard deviation 2.6) were measured. We measured 13,100 ppm (SD 380) under surgical mask and 13,900 ppm (SD 370) under FFP2 mask in inhaled air. A linear model with age as a covariate showed a highly significant effect of the condition (p < 1*10−9). We measured 2,700 ppm (SD 100) CO2 at pre-baseline and 2,800 ppm (SD 100) at post-baseline, a non-significant small difference. Appropriate contrasts revealed that the change was due to the masks only and the difference between the two types of masks was small and not significant. Wearing of NMC (surgical masks or FFP2- -masks) raises CO2 content in inhaled air quickly to a very high level in healthy children in a seated resting position that might be hazardous to children's health.