[Chemical pollution of indoor air and its effects on health]

Many studies have demonstrated how exposure to chemical pollutants in indoor air has adverse effects on health and comfort. Volatile organic compounds (VOCs), formaldehyde, ozone, particulates, fibres and environmental tobacco smoke have all been implicated. VOCs include a wide range of chemical substances which irritate mucosa. Many are neurotoxic and some are suspected or known to be carcinogenic e.g. benzene. Formaldehyde, the simplest and most common aldehyde in indoor air, is a powerful irritant to the skin, eyes, nose and upper airways. Given its close association with nasal-pharyngeal tumours, it has recently been classified as a certain carcinogen for humans. Exposure to ozone may cause airway irritation and inflammation, reduce the ventilation function and increase reversible bronchial reactivity. In the general population it increases the mortality rate and the number of hospital admissions for respiratory diseases. Airborne particles, a mixture of organic and inorganic substances, are powerful irritants for the eyes and mucosa and can cause adverse cardiovascular effects. Apart from indoor environments, exposure to asbestos fibres has been associated with an increased risk of respiratory diseases such as pneumoconiosis lung cancer and mesothelioma. Synthetic mineral fibres cause transient irritation and inflammation of the skin, eyes and upper airways. Recent observations have confirmed that exposure to environmental tobacco smoke, which is widespread in workplaces, increases the risk of lung cancer, irritative respiratory and ocular symptoms and cardiovascular diseases.