The assertion recently made by Nicole Nordlund to the Conway School Board that studies have shown masks carry serious illness and transmit it to students and a letter by Michael Knudson published July 13 about a study showing the wearing of masks by children causes dangerous levels of inhaled carbon dioxide demonstrate the importance of critical review of medical articles.

As a retired surgeon (who wore surgical masks all day), I found this a little surprising. Nordlund did not give any citations for the studies she asserted. Knudson did.

In this column, I will not take a position on whether masks should be required but will illustrate the importance of using sound information to make such decisions.

The desire for rapid dissemination of information regarding COVID-19 resulted in a profusion of open-access online articles, some with minimal or no critical review. Many of these articles were later been retracted, but by then the damage had been done as they had found their way onto websites and social media.

Critical analysis of medical literature takes training. I was trained in evaluating scientific literature for many years during medical school, residency and in practice.

Be very cautious about accepting information found on websites or Facebook without investigating further. And never retweet or state such information as fact in a public forum unless you have evaluated the article yourself or had help from a trusted individual with the appropriate skills.

When analyzing an article, look at the source. Does it come from a peer-reviewed journal? Investigate the credentials of the author. Is there a conflict of interest based on the funding of the study, which might lend bias to the results?

Read the whole paper, assessing the study protocol. Was it randomized with a control group? Were the study groups equivalent? Were the findings statistically significant? Read the discussion section in which responsible authors point out the potential shortcomings of their paper and how it could be misconstrued. Read the references cited at the end of the article as well.

Knudson stated that the study regarding CO2 and masks was published in the New England Journal of Medicine. It was not. It was published as a “research letter” on, an open access online publication with minimal review. It was shorter than this column and very short on details. Links to supplements allowed me to delve into the study protocol. A short Google search revealed that the author, Harald Walach, is a psychologist who researches parapsychology and has a known bias against masks. He published two papers about COVID in June this year, one about vaccines, which was quickly retracted, and this study about masks and CO2, which is being re-evaluated by jamanetwork.

The university with which he was affiliated terminated his affiliation, stating that the vaccine article “lacked scientific diligence and proper methodology.”

I reviewed Walach’s study protocol. The measurement technique he used was faulty. He measured the inhaled CO2 concentration with a tube placed under the mask, near the nose, using a device designed to measure CO2 in incubators rather than an appropriate medical device. The manual for the device states that the air sample to be tested must be drawn in through the sampling tube for 30 seconds to be valid. In that time period, there would be about 10 inhalations and exhalations, meaning he could not possibly have measured the inhaled CO2 concentration. He was measuring the mix of inhaled and exhaled CO2 inside the mask. Since exhaled CO2 concentration is 100 times greater than the concentration in ambient air, it is no wonder that he demonstrated an elevated level of CO2 inside the mask.

I estimate there is about 5 ml of trapped air beneath a surgical or cloth mask. This small amount of re-breathed air will result in an insignificant increase in the inhaled CO2 as it is far less than the 150 ml of re-breathed air normally in our respiratory passages. About 95 percent of the inhaled air comes from outside the mask, making this 5 ml of elevated CO2 irrelevant. No conclusions can be reached regarding the blood level of CO2 as it was not measured in this study.

My investigation of this paper demonstrates the pitfalls in accepting the findings of papers which are shared on websites or social media without critical analysis.

Nordlund needs to supply the references for her assertion to the Conway School Board that masks cause disease and in a letter to the Sun so that they can be critically analyzed.

Jerry Knirk is a Democratic state representative from Freedom.

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