A review of studies from 12 countries found a weighted average concentration about four times the World Health Organization’s guideline for fine particles.
The review examined research published from 2010 to 2025 on outdoor particle concentrations near cement plants. Twenty-one studies from 12 countries were included in the qualitative review, while six provided enough information for a quantitative analysis.
Using a random-effects model, the researchers estimated a weighted average fine-particle concentration of 20.76 micrograms per cubic metre. This was about 4.2 times the WHO’s 2021 annual guideline of 5 micrograms per cubic metre, but the researchers described the result as a summary of the observed concentrations rather than a single value that applies to every cement plant.
Fine-particle levels near plants
The six studies included in the meta-analysis reported average fine-particle concentrations ranging from 14.34 to 32.39 micrograms per cubic metre. Their weighted average was 20.76 micrograms per cubic metre, with a 95% confidence interval of 16.61 to 24.91.
The estimated average was above the WHO 2021 annual guideline of 5 micrograms per cubic metre and fell between the WHO’s interim targets known as IT-3 and IT-2. The studies varied greatly: statistical tests indicated very high heterogeneity, with I² at 97.9%. The researchers also qualitatively reviewed information on particle composition, sources and health-related outcomes, but the abstract does not report specific combined results for those areas.
Why the comparison matters
The findings provide descriptive evidence that fine-particle concentrations measured around cement plants can be substantially higher than the WHO annual guideline. This may help inform exposure management and future work on buffer zones and health-based assessment frameworks near cement plants.
The review also points to the limits of relying only on the total mass of particles. The researchers said future assessments should include chemical composition and measures related to toxicity, which could provide more information about the potential significance of the particles being measured.
Evidence and key limits
This was a systematic review and meta-analysis, not a new measurement campaign or an experiment. The researchers followed PRISMA 2020 guidance, searched PubMed and Web of Science in January 2026, and assessed the robustness of the pooled estimate with leave-one-out sensitivity analysis.
Only six of the 21 included studies reported, or allowed the researchers to derive, the mean, standard deviation and sample size needed for the meta-analysis. The very high heterogeneity means the pooled value should be understood as a weighted summary of the concentrations observed in those studies, not as an estimate for every cement plant. Differences in sampling duration were an important limitation, and the abstract does not establish a direct health effect from the reported concentrations.
// Source
Korean Journal of Environmental Health Sciences · 2026 · DOI: 10.5668/jehs.2026.52.4.374
Authors: Young-Hyun Kim, Ye-Jin Shim, Cheol-Min Lee
Institutions: Seokyeong University
