Response to comments from Mark Mendell, Lars Molhave and Peder Wolkoff

The authors agree with the arguments by Mendell for seeking a composite index relating indoor environmental quality (IEQ) and building related symptoms (BRS). The determination of the (IPSI) Indoor Pollutant Standard Index is a useful first-step for the practitioners. It provides scope for further refinement that could incorporate the relative impact of more than just one measured indoor pollutant.