A systematic review of biomonitoring of children's indoor air exposure in schools and homes

Abstract Background Today, children spend a lot of time indoors, particularly at home and school, so the quality of indoor air is a crucial factor in determining their health. Human biomonitoring has unique advantages for evaluating internal doses of indoor air pollution. This review aimed to summarize studies assessing children's specific indoor exposures in school and home settings using biomonitoring combined with external measurements. Methods A systematic search was conducted in PubMed, Web of Science, Scopus, and Embase databases for peer-reviewed literature on biomonitoring of children (ages 6-12) for selected indoor air pollutants, including 17 volatile organic compounds, 9 semi-volatile organic compounds, and 21 relevant chemical families. Data on geographic location, biomarkers, biological specimens, pollutant classes, and analytical techniques were extracted and analyzed. Results This review summarized the indoor air pollutants, biomarkers, and analytical techniques used in studies from 53 countries described in 79 articles. Most studies were conducted in Europe (40.51%) and Asia (30.38%). Mostly, aromatic hydrocarbons were analyzed (18 times via biomonitoring, of which 8 studies included environmental measurements). Across all pollutant groups, the most common biomarkers of exposure included metabolites and their parent compounds in urine, whereas eNO in exhaled breath was the main biomarker of effects. GC-MS and LC-MS were the most popular techniques for analyzing biological and environmental samples. High heterogeneity was observed in study designs and exposure metrics across studies. Conclusions The lack of consistent study design and exposure assessment protocols posed challenges for direct comparisons and meta-analyses. It is recommended to standardize biomonitoring methods and integrate them with environmental measurements. These insights can inform future study designs to better understand and reduce children's exposure to indoor air pollution. Key messages • This review compiled the current biomonitoring and environmental approaches used to assess children’s exposure to selected indoor air pollutants in school and home environments. • The findings revealed gaps in harmonized approaches and call for standardization and integration of biological and environmental monitoring to better understand children's indoor air exposures.