Hey!
Your co2 levels look fine, but I am VERY concerned by your CO levels. CO is carbon monoxide and 261 ppms is quite a bit. The levels for CO are as follows;
50 PPM None for healthy adults. According to the Occupational Safety & Health Administration (OSHA), this is the maximum allowable concentration for continuous exposure for healthy adults in any eight-hour period.
200 PPM Slight headache, fatigue, dizziness, and nausea after two to three hours.
400 PPM Frontal headaches with one to two hours. Life threatening after three hours.
800 PPM Dizziness, nausea, and convulsions within 45 minutes. Unconsciousness within two hours. Death within two to three hours.
1,600 PPM Headache, dizziness and nausea within 20 minutes. Death within one hour.
HCHO is Formaldehyde, I'm guessing your furnace or something is a gas furnace and it might be burning too rich/lean and is producing by products from the mercaptans in the gas.
Hope this helps.