“There is now good awareness of the risks from badly maintained gas appliances, radioactive radon gas and second-hand tobacco smoke, but indoors we can also be exposed to NO2 [nitrogen dioxide] from gas cooking and solvents that slowly seep from plastics, paints and furnishings.
“The lemon-and-pine scents that we use to make our homes smell fresh can react chemically to generate air pollutants, and ozone-based air fresheners can also cause indoor air pollution.”