A lot of anti-mask people, including a doctor who just direct messaged me, bring up fears about CO2 levels in masks. They just can’t let people make their own choices. They point to a study or two that measured high CO2 levels around masks. But the measurement apparatus and methods of these reports are fraught with problems. CO2 molecules are tiny, like footballs being kicked through the uprights of N95 mask fibers. Even so, I’d trade any short term, potentially higher CO2 level in the first part of an inhaled breath through a mask for less SARS CoV2 in my respiratory system on a plane any day.
Even more granular, or should I say molecular, considerations:
Let's break this down into two parts: the size of CO2 molecules and the filtration capabilities of N95 masks.
Size of CO2 molecules: Carbon dioxide (CO2) molecules are extremely small. The diameter of a CO2 molecule is approximately 0.33 nanometers (nm) or 3.3 angstroms (Å).
N95 mask filtration: N95 masks are designed to filter out at least 95% of airborne particles that are 0.3 microns (300 nanometers) in diameter or larger. This size (0.3 microns) is considered the most penetrating particle size and is therefore used as the standard for testing these masks.
Comparison: The CO2 molecule (0.33 nm) is significantly smaller than the particles N95 masks are designed to filter (300 nm). In fact, CO2 molecules are approximately 900 times smaller than the smallest particles N95 masks are rated to filter effectively.
Given this size difference, CO2 molecules can easily pass through N95 mask filters. This is why N95 masks do not interfere with normal breathing - they allow gases like oxygen, carbon dioxide, and nitrogen to pass through freely while still filtering out much larger particles like dust, bacteria, and virus-carrying respiratory droplets.
It's important to note that while N95 masks can filter some particles smaller than 0.3 microns due to various physical mechanisms (like diffusion and electrostatic attraction), they are not designed to filter out individual gas molecules like CO2.
