If you "improved" the insulation on your domicile in the past few years and/or people in your household began working at home more, consider the average CO2 may

If you "improved" the insulation on your domicile in the past few years and/or people in your household began working at home more, consider the average CO2 may have increased notably (which will vary by season) leaving you foggier. Try cracking windows for a cross-breeze (or more than cracking them if the temp is not too different outside from inside). Aranet4's are an investment but can be worthwhile once you recognize it as an issue for you.