Radon is a naturally occurring radioactive gas produced by uranium decay in soil and rocks, and the dominant source of natural ionizing radiation exposure. Prolonged indoor inhalation of its alpha-emitting progeny is the second leading cause of lung cancer after tobacco smoking. This study provides the assessment of indoor radon concentrations in 25 dwellings across five villages in a mountainous region in northern Pakistan. These villages (Kamra, Thoon, Paija, Bhattian, and Chaffar) are in Kotli Sattian, a seismically active sub-Himalayan township in Rawalpindi District, Punjab, Pakistan. The CR-39 solid-state nuclear track detectors were used passively at head height for 60 days for track counting. The overall mean radon concentration was 43.75 ± 31.04 Bq？m？3, ranging from 13.77 to 135.76 Bq？m？3. Village-level means ranged from 33.10 Bq？m？3 (Bhattian) to 51.85 Bq？m？3 (Chaffar). Newly constructed concrete and brick dwellings recorded a higher mean (49.44 Bq？m？3) than older mud and wood structures (35.42 Bq？m？3), attributable to the elevated radium content of modern building materials. The mean annual effective dose of 0.11 mSv？y？1 is well below the 1 mSv？y？1 public limit. The Excess Lifetime Cancer Risk (ELCR) of 0.37 × 10？3 and Lung Cancer Risk (LCR) of 5.07 × 10？3 both fall within internationally accepted limits. These findings establish a radiological baseline for Kotli Sattian and highlight the need for year-round monitoring and targeted remediation in dwellings proximal to active fault structures.
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