Atmospheric occurrence and socioeconomic drivers of cyclic volatile methyl siloxanes across China
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China is a global hotspot for atmospheric D4, a chemical primarily from industrial silicone production.
D4 pollution stems mainly from industry, while D5 is linked to the use of personal care products.
Higher personal income, not just population, better predicts D5 levels from consumer product use.
To cut global D4 pollution, efforts must focus on industrial sources in major producing countries.
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ABSTRACT
Cyclic volatile methyl siloxanes (cVMS) are high-production volume chemicals, and their release into the atmosphere has raised increasing concerns regarding potential adverse effects on human health and the environment. China dominates global cVMS production, particularly octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5); but their atmospheric occurrence and socio-economic drivers are largely unknown. Here, we report initial findings from mobile and in situ measurements of atmospheric D4 and D5 across China using the Vocus proton-transfer-reaction time-of-flight mass spectrometer. We observed high concentrations of D4 (up to 139 pptv) and D5 (up to 176 pptv), induced by strong chemical factory emissions. The ambient mixing ratios of both chemicals increased from north to south and west to east, and D4 was one order of magnitude higher than D5. Moreover, we found that residential income better explained the domestic and global heterogeneity of cVMS compared to population density. These findings pave the way for exploring large-scale emission inventories and environmental impacts of atmospheric cVMS, highlighting China’s substantial contribution to global atmospheric D4 levels primarily from industrial production and underscoring the need to consider regional economic factors in global D5 emission models. -
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Chang Y., Cheng L., Yang Y., et al. (2026). Atmospheric occurrence and socioeconomic drivers of cyclic volatile methyl siloxanes across China. The Innovation Geoscience 4:100155. https://doi.org/10.59717/j.xinn-geo.2025.100155
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Chang Y., Cheng L., Yang Y., et al. (2026). Atmospheric occurrence and socioeconomic drivers of cyclic volatile methyl siloxanes across China. The Innovation Geoscience 4:100155. https://doi.org/10.59717/j.xinn-geo.2025.100155
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Figure 1.
Locations of mobile and in-situ measurements.
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Figure 2.
Time series of atmospheric D4 and D5 and associated parameters
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Figure 3.
The correlation between atmospheric D4 and D5
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Figure 4.
Observations in downtown Shanghai
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Figure 5.
Global distribution of D4 and D5 in the Atmosphere
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Figure 6.
Relationships between global atmospheric D4/D5 concentrations, population density, and inter-compound correlations
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Figure 7.
Silicone Development Trends
