What are some gases other than oxygen in your home?

Nitrogen is the most common gas in any home. It is fairly inert. Carbon dioxide will also be present at fairly high levels in most homes, though usually less than oxygen. Water vapor is also present in homes. Inside air will match roughly the proportions of gasses of outside air in homes with good ventilation.

Answer:

The composition of air is
  • 78% Nitrogen
  • 21% Oxygen
  • 1% Argon
  • 380 ppm Carbon dioxide outside, up to 1000 ppm inside.
  • Trace amounts of methane.

Also, homes in parts of the world where naturally occurring radon levels are high will contain varying amounts of radon gas (the mean concentration varies from less than 10 Bq/m3 to over 100 Bq/m3 in some European countries.) Radon can accumulate in poorly ventilated homes in areas with high background levels of the gas and can pose a significant health risk.