Indoor contamination with critical substances can be as high as 10 times the external contamination level of inner city environments. Formaldehyde has been classified as carcinogenic and may be released into the environment from carpets, furniture, adhesive, paints, and varnishes. Paints emit chemicals long
after they have been applied and care needs to be taken when choosing suppliers to reduce emissions to a minimum, particularly when people living in the space are young or elderly. Consider choosing natural fibres, wood, clay, lime etc. when possible, to keep your environment as healthy.