Exposure to volatile organic compounds in indoor/outdoor environments and methodological approaches for exposure estimates -the European paradigm
D. Kotzias
Abstract
People spend a significant part of their time (on average 85 to 90%) in confined spaces (homes, office buildings, schools and transport means) exposed to a complex mixture of air contaminants at concentration levels often several times higher than outdoors. For many chemicals (and their combinations) present in indoor environments, the risk to human health is almost unknown and difficult to predict because of the lack of toxicological data and information on the dose-response characteristics in human or animal models. Chemicals in indoor environments include volatile organic compounds (VOCs) of different chemical classes, aromatics (benzene, toluene, naphthalene), carbonyls (aldehydes and ketones), chlorinated hydrocarbons (tri-, tetrachloroethylene), terpenes (limonene, pinene), nitrogen dioxide, carbon monoxide, substances often adsorbed on particles as well as compounds produced during reaction processes indoors. Exposure of humans to air pollutants can be measured or modelled provided that reliable data are available on the concentration and fate of these compounds in indoor and outdoor environments for model calculations. The aim of the paper is to present the approaches and guidelines proposed by the EU and WHO for the prioritization in assessment and regulation of chemicals in indoor environments. Furthermore, to provide descriptive information on various methods for sampling and measuring procedures of VOCs applied in Europe for human exposure estimates. The focus is on measuring campaigns at pan-European level (EXPOLIS, MACBETH, AIRMEX and SINPHONIE) at different locations/cities in Europe, and on priority air contaminants frequently present indoors, notably benzene, formaldehyde and terpenes. The latter participate in indoor air chemistry processes leading to chemical products e.g. 4-acetyl-1-methylcyclohexene (4-AMCH), 3-isopropenyl-6-oxoheptanal (IPOH), 4-oxopentanal (4-OPA) with rather unknown effects on human health and well-being.