Unmasking Ethylbenzene Exposure in Residential Buildings and Schools With a Comprehensive Systematic Review

In the contemporary context of lifestyles, where individuals typically spend around 90% of their lifetimes indoors, indoor air quality becomes a crucial concern with implications for human health. This research examines ethylbenzene concentration in residential and educational buildings, evaluating associated risks. Extensive searches of databases such as Science Direct, PubMed, and Springer were conducted, encompassing data from inception to April 13^th, 2023, focusing on English-language sources. Search terms contained “BTEX,” “Indoor,” “Cigarette,” “Waterpipe,” “Shisha,” “Hookah,” “Tobacco,” and “ETS”. Thirty-one studies were deemed eligible for analysis. Time-series analysis does not show significant trends for ethylbenzene in both indoor and outdoor environments over years. However, ethylbenzene concentrations in residential buildings generally exceeded those in schools (7.49 ± 9.86 vs. 4.67 ± 7.81  μg/m³). Moreover, smoking within residential buildings correlated with higher ethylbenzene concentrations compared to nonsmoking environments (17.75 ± 18.96 vs. 7.16 ± 7.79  μg/m³). Additionally, indoor ethylbenzene concentrations surpassed outdoor concentrations. The calculated cancer risk for all studies related to residential buildings, across genders and age groups, and schools in Group 3, exceeded the established permissible limit (i.e., 10⁻⁶). Conversely, the calculated hazard quotient for all studies remained below the permissible limit (i.e., 1).