Regulations aggregate exposure

Shurdut, B.A., L. Barraj, and M. Francis. 1998. Aggregate exposures under the Food Quality Protection Act An approach using chlorpyrifos. Regul. Toxicol. Pharmacol. 28(2) 165-177. 

Relevant threshold limit values for terpenes are rare because of a lack of basic information about specific terpene products and by-products on the one hand, and occupational and environmental exposures on the other hand. The threshold limit values which have been documented the best concern oil of turpentine. A MAK-value of 100 ppm is defined in German regulations and noted to be dermally sensitive. For other terpenes, such as d-limonene which is also classified as dermally sensitive, it has not yet been possible to establish a MAK-value because of a lack of information of their effects on animals or humans. With terpenes, as is often the case, aggregate concentration parameters are used as limit values such as the minimum level goals recommended by the former German Federal Flealth Authority. These suggested minimum values bear in mind actual levels detected in indoor areas. 

---