A Meta-Analysis of Ambient Particulate Matter Concentrations around Cement Plants

Abstract

Background: Cement production emits particulate matter (PM) during raw material grinding, clinker calcination, final grinding, and storage.Concerns remain regarding PM exposure and related health effects among nearby residents, yet quantitative syntheses of ambient PM concentrations around cement plants remain limited.Objectives: This study aimed to synthesize ambient PM 2.5 concentrations around cement plants through meta-analysis and qualitatively summarize chemical composition, source contribution, and health-related outcomes.Methods: Following PRISMA 2020 guidelines, PubMed and Web of Science were searched in January 2026 for studies (2010~2025) measuring PM 2.5 or PM 10 near cement plants.Twenty-one studies from 12 countries were included in the qualitative synthesis, and six with reported or derivable mean, standard deviation, and sample size were meta-analyzed.A pooled mean PM 2.5 concentration was estimated using a random-effects model, with robustness assessed by leave-one-out sensitivity analysis. Results:The study-level mean PM 2.5 concentrations used in the analysis ranged from 14.34 to 32.39 µg/ m 3 (median 20.93; geometric mean 20.31).Given very high heterogeneity (I 2 =97.9%), the inverse-variance random-effects pooled estimate (20.76 µg/m 3 , 95% CI: 16.61~24.91)was interpreted as a weighted summary of the observed concentration distribution rather than an estimate of a single true value.This level was approximately 4.2 times the WHO 2021 annual guideline of 5 µg/m 3 , and it fell between interim targets IT-3 and IT-2. Conclusions:The weighted summary of PM 2.5 concentrations around cement plants was above the WHO annual guideline, although differences in sampling duration should be considered.Future exposure assessments should incorporate chemical composition and toxicity-based indicators beyond mass concentration.These findings may serve as descriptive evidence to inform exposure management and to support the future development of buffer zone planning and health-based assessment frameworks.