Radon gas emission is an emerging phenomenon that modern lifestyles have become a potential danger to humans. So, stochastic evaluation of the amount of this hazardous gas in urban scale and residential buildings can be critical in identifying environmental health risks. A novel fuzzy Radon Hazard Index is proposed in this research to assess statistical radon environmental health risks. The output index FRHI ranges from 0 (No Hazard) to 100 (The highest degree of hazard). The approach can serve as a circumstantially integrated standard for stochastic radon risk assessment and management because innovation fuzzifies this field's most important stochastic standards. In this study, first, Radon was measured in the urban scale building, and then, Arc GIS software prepared natural Radon emission zoning maps at urban and geological scales. A residential building unit in one of the critical areas has been selected. Some corrective actions have been adopted to reduce Radon in urban building units. The FRHI Assessment for stochastic environmental health risk evaluation shows that the initial fuzzy level for the mean value of FRHI is Hazardous (for FRHI value equal to 60.1) determined by Red color. This is while the Maximum FRHI level for 48 hours after installation is Rather Hazardous (for FRHI value equal to 44.8) determined with orange color, and the maximum statistical environmental health risk after steady-state installation would fall into an improved category. So identifying critical areas can provide exceptional control at the urban scale building that reduces the risks of natural Radon.

Radon gas emission is an emerging phenomenon that modern lifestyles have become a potential danger to humans. So, stochastic evaluation of the amount of this hazardous gas in urban scale and residential buildings can be critical in identifying environmental health risks. A novel fuzzy Radon Hazard Index is proposed in this research to assess statistical radon environmental health risks. The output index FRHI ranges from 0 (No Hazard) to 100 (The highest degree of hazard). The approach can serve as a circumstantially integrated standard for stochastic radon risk assessment and management because innovation fuzzi es this eld's most important stochastic standards. In this study, rst, Radon was measured in the urban scale building, and then, Arc GIS software prepared natural Radon emission zoning maps at urban and geological scales. A residential building unit in one of the critical areas has been selected. Some corrective actions have been adopted to reduce Radon in urban building units. The FRHI Assessment for stochastic environmental health risk evaluation shows that the initial fuzzy level for the mean value of FRHI is Hazardous (for FRHI value equal to 60.1) determined by Red color. This is while the Maximum FRHI level for 48 hours after installation is Rather Hazardous (for FRHI value equal to 44.8) determined with orange color, and the maximum statistical environmental health risk after steady-state installation would fall into an improved category. So identifying critical areas can provide exceptional control at the urban scale building that reduces the risks of natural Radon.