Exposure to Benzene Concentrations in Residential Buildings and Schools: A Risk Assessment and Comprehensive Systematic Review Publisher



Momen A ; Taherkhani A ; Shahabi K ; Rostami R
Source: Water, Air, and Soil Pollution Published:2026

Abstract

Indoor air quality (IAQ) is a critical health concern, as individuals spend approximately 90% of their time indoors. This study systematically reviewed and meta-analyzed benzene concentrations in residential buildings and schools to assess exposure and associated health risks. Comprehensive searches in ScienceDirect, PubMed, and Springer databases (up to April 13, 2023) identified 34 eligible studies from 444 screened. Search terms included “BTEX,” “Indoor,” “Cigarette,” “Waterpipe,” “Shisha,” “Hookah,” “Tobacco,” and “ETS.” Indoor benzene concentrations showed an increasing trend over time, whereas outdoor levels declined. Benzene levels were significantly higher in schools than in residential buildings (21.47 ± 45.80 vs. 17.57 ± 25.67 µg/m3, p < 0.001). Smoking significantly influenced indoor residential concentrations (p = 0.021). Indoor environments consistently exhibited higher benzene concentrations than outdoor environments (24.73 ± 42.39 vs. 15.54 ± 41.51 µg/m3, p = 0.288). Smoking and geographic region influenced indoor levels, while outdoor concentrations were affected by region (p < 0.05). Cancer risk (CR) exceeded permissible limits (10⁻⁶) across all studies, whereas hazard quotients (HQ) were below acceptable thresholds (1). The pooled benzene concentrations were 7.063 [95% CI: 5.853–8.524] for indoor environments, 3.161 [95% CI: 2.582–3.870] for schools, 7.959 [95% CI: 6.714–9.436] for residential buildings, and 4.333 [95% CI: 3.498–5.381] for outdoor environments, all with high heterogeneity (I2 = 100%). This study highlights significant variability in benzene exposure across environments and underscores the urgent need to address elevated levels in schools and residential buildings to mitigate health risks. © 2025 Elsevier B.V., All rights reserved.