I've worked in gas appliance design since 2007. I can tell you that emissions by stoves have risen dramatically. (There are limits on CO (800 ppmaf), but not CO2 or NO2). This can be attributed, largely, to stove manufacturers pushing the limits on power output. Some residential stove burners are over 20,000BTU/hr each. And that is a fully unvented, poorly performing, impinging, bunsen burner type flame, not a modern, vented, low NOx radiant like could be in the gas furnace (where the spec is 400 ppmaf). Couple burning enough gas to heat a whole house with a modern, tighter home construction and bingo! Yes it is poisoning us.