Indoor Air Quality Guidelines -Appendix A

SOME COMMON INDOOR AIR CONTAMINANTS 

Carbon dioxide 

Carbon dioxide is present in the unpolluted atmosphere at a concentration of about 0.03% percent but since about 5% of the air we breathe out is carbon dioxide the level increases in inadequately ventilated occupied rooms. The level of carbon dioxide is therefore often used to assess the efficiency of ventilation. Outside sources include vehicle exhaust fumes or other exhausts. 

Carbon monoxide 

Any process of combustion can produce carbon monoxide, including cooking and tobacco smoking. A major source of carbon monoxide is vehicle exhaust.

 Formaldehyde 

Formaldehyde is a colourless gas with a pungent odour. It is found in hundreds of different products, including insulation material, ceiling tiles, particle board, plywood, office furniture, carpet glues, various plastics, synthetic fibres in rugs, upholstery and other textiles, pesticides, paint and paper. Levels of emission increase with temperature. 

Ozone 

Ozone is naturally present in the air since it is produced from oxygen by ultraviolet radiation. However, it can also be produced by electrical discharges and is emitted by some items of electrical equipment such as photocopiers and electrostatic precipitator devices used to clean the air by removing dust.