Health risks from indoor air pollutants: public alarm and toxicological reality

The air, particularly the indoor air, contains a considerable burden of unwanted pollution. Overall there may be thousands of pollutants. They are brought in with the outside air or are generated from or within buildings. Most will be present in minute amounts but several will be present in measurable quantities. The reaction of people to the components of this pollution has little to do with toxicological assessment but is more concerned with political responses and media scares. The health effects from exposure to the very low levels 9ommonly found in the indoor environment of materials such as combustion products, whether from coal, petrol or tobacco or to lead or asbestos fibres, are probably negligible but we worry about them. On the other hand, gases such as carbon monoxide or nitrogen dioxide which are not infrequently present in dangerous concentrations, many solvents and dust-generating DIY projects cause little concern. The distinction between concern and indifference is made without reference to any toxicological knowledge. Although it is certainly prudent, through source control, design and ventilation of buildings, to reduce all pollutants to the lowest level, concentrating on media favourites rather than more important dangers, including disease transmission, may well be a poor use of our resources.