Target levels--tools for prevention.
Although occupational exposure limits are sought to establish health-based standards, they do not always give a sufficient basis for planning an indoor air climate that is good and comfortable for the occupants in industrial work rooms. This paper considers methodologies by which the desired level, i.e., target level, of air quality in industrial settings can be defined, taking into account feasibility issues. Risk assessment based on health criteria is compared with risk-assessment based on "Best Available Technology" (BAT). Because health-based risk estimates at low concentration regions are rather inaccurate, the technology-based approach is emphasized. The technological approach is based on information on the prevailing concentrations in industrial work environments and the benchmark air quality attained with the best achievable technology. The prevailing contaminant concentrations are obtained from a contaminant exposure databank, and the benchmark air quality by field measurements in industrial work rooms equipped with advanced ventilation and production technology. As an example, the target level assessment has been applied to formaldehyde, total inorganic dust and hexavalent chromium, which are common contaminants in work room air.