Calibration of LR-115 Type II SSNTDs and Indoor Radon-222 Assessment in Man, Côte dIvoire

This study focused on the calibration of LR-115 type II solid-state nuclear track detectors (SSNTDs) and the assessment of indoor radon-222 concentrations in dwellings in Man, Côte d’Ivoire. Detector calibration was performed in a certified radon chamber by exposing the LR-115 to a radon concentration of 2.29 kBq·m⁻sup3/sup for 64.33 h. After chemical etching and microscopic analysis, a calibration factor of 198.35 ± 21.43 tr/cmsup2/sup/kBq·msup-/supsup3/sup·h was obtained. Twenty-six detectors were then deployed in dwellings for three months. Radon concentrations ranged from 52.13 to 219.4 Bq/msup3/sup, with an average of 119.69 ± 13.36 Bq/msup3/sup (120 Bq.msup-3/sup). Most measured values were below internationally recommended reference levels; however, several sites (M1, M6, M9, M14 and M18) exceeded 150 Bq·msup-/supsup3/sup. Apart from geological factors, elevated concentrations were mainly associated with poor ventilation and low foundation height. Excess cancer risk (ECR), estimated using EPA and UNSCEAR coefficients, showed significant spatial variability. According to the EPA model, ECR values ranged from 32 to 98 for site M19 and from 134 to 410 for site M14, while UNSCEAR-based estimates ranged from 41 to 111 at M19 and from 174 to 469 at M14. Corresponding annual effective doses varied between 2.09 and 8.81 mSv·ysup-/supsup1/sup. These findings highlight the spatial variability of indoor radon concentrations linked to local geology and building characteristics, and provide essential baseline data for radon mapping and risk mitigation strategies in Côte d’Ivoire. The results support targeted ventilation improvements and foundation design considerations within existing housing stock without altering measured.