[en] This paper presents a preliminary review of the literature and an estimation of the range of dilutions that are possible for roof-top and elevated side-of-house emission releases. Operating characteristics of typical subslab systems are used with estimated diluations to assess possible emissions reentrainment and downwind effects on houses. Surveys of government and private sector radon-mitigation activities indicate that subslab radon-mitigation systems account for more than 50% of all installed systems. While ongoing mitigation research and demonstration projects show promise for optimizing system designs in the future, current practice relies on the installation of robust (effective oversized) systems. Such systems can remove large quantities of radon-laden soil gas from underneath and from around mitigated houses