"To qualify as HEPA by US government standards, an air filter must remove (from the air that passes through) 99.97% of particles that have a size of 0.3 µm."
Carbon monoxide is a few orders of magnitude too small to be caught by a HEPA filter, in fact a filter that could filter CO would filter oxygen and nitrogen as well. Such a filter would just be a pump.
Carbon monoxide is a few orders of magnitude too small to be caught by a HEPA filter, in fact a filter that could filter CO would filter oxygen and nitrogen as well. Such a filter would just be a pump.
There, however, exists a patent for a filter for CO, it works by converting the CO to CO2: https://www.google.com/patents/US5564065