He there!<p>During evenings we burn quit some candles in our living room. Our house is well isolated (we have a heat pump for heating our house), so we have to ventilate a lot.
During evenings we notice we got sleepy very early in the evening. When we go to bed we stay awake for quit some time. This made me wonder if there was a coloration with the candles and us feeling sleepy early, so I bought a CO2 meter.<p>After a few test it became clear that after burning the candles for like 1,5 hours the CO2 level was already 2 to 3 times higher than before the candles burned.<p>Maybe an open door: if you burn a lot of candles or are with a lot of people in a smaller room, don’t forgot to ventilate! This will make you stay awake longer!
If you do anything that involves having an open flame indoors (and I'm including the flame inside a gas / propane fueled furnace, water-heater, etc., or a gas stove) you should have one or more CO alarms in your home as well. CO2 has its own issues, but CO is a very powerful asphyxiant and can very easily be deadly.<p><a href="https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Carbon-Monoxide-Information-Center/Carbon-Monoxide-Questions-and-Answers" rel="nofollow">https://www.cpsc.gov/Safety-Education/Safety-Education-Cente...</a>
Most candle wax is made from paraffin (derived from petroleum). More expensive candles made from beeswax won't be so polluting indoors, but a candle flame will always produce some soot.<p>An alternative is a fake LED candle with flickering 'flame'. All the ambience of a real candle without the noxious emissions! Of course, you still need a source of power, but LED candles can be powered by batteries and the battery power lasts longer than a wax candle melting.
Reddit had quite a story about CO poisoning. WBUR went on to summarize and expand upon it, making for a good (and somewhat alarming) read:
<a href="https://www.wbur.org/endlessthread/2018/03/09/something-wicked" rel="nofollow">https://www.wbur.org/endlessthread/2018/03/09/something-wick...</a>
CO2 is the obvious connection here, but there's another effect at
play. Candles tend to flicker in the 8Hz - 15Hz frequency range due to
turbulence around the flame. This can be quite soporific. It's likely
a neural entrainment. I wonder if LED fake candles that mimic the
flicker have a similar effect.