EA-IRMS: Using isotope fingerprints to track sources of PM2.5 in air pollution

Importance of the Topic

Air pollution by fine particles affects climate dynamics and human health through reduced visibility and respiratory and cardiovascular risks. Identifying the sources of PM2 5 is essential for effective air quality management and emission control strategies.

Objectives and Study Overview

This study aimed to trace the origin of PM2 5 particles in Seoul South Korea during winter 2016–2017 by applying stable isotope fingerprinting of carbon nitrogen and sulfur in particulate samples.

Methodology and Instrumentation

PM2 5 particles were collected on quartz microfiber filters using a high volume impactor sampler. Filter subsamples were weighed into tin capsules and combusted in the EA IsoLink IRMS System with MAS Plus autosampler. Gaseous products N2 CO2 and SO2 were analyzed in triplicate with a 10 minute runtime per sample and calibrated against international reference materials.

Instrumentation Used

• Thermo Scientific EA IsoLink IRMS System
• MAS Plus Autosampler
• High volume PM2 5 impactor sampler

Key Results and Discussion

Isotope values indicated a dominant fossil fuel signature. Carbon values (δ13C) ranged from -26.33 to -27.59 per mil consistent with vehicle emissions. Nitrogen values (δ15N) from 4.19 to 8.58 per mil reflected coal combustion and traffic sources. Sulfur values (δ34S) from 4.01 to 7.35 per mil confirmed coal derived sulfate rather than maritime or biogenic contributions. Trends in isotope signatures aligned with PM2 5 concentration changes during the sampling period.

Benefits and Practical Applications

• Rapid analysis with 10 minute throughput per sample
• No chemical cleanup reducing labor and consumable costs
• Automated workflow enabling high sample throughput
• High sensitivity and data quality comparable to published studies

Future Trends and Opportunities

Integration with real time monitoring and spatial mapping will enhance source apportionment accuracy. Expanding isotope reference libraries and coupling with complementary analytical techniques will support more detailed emission inventories. This approach can inform policy decisions and improve urban air quality management.

Conclusion

Direct isotope fingerprinting of PM2 5 on quartz filters using the EA IsoLink IRMS System offers an efficient reliable method for source identification. Results confirmed predominant fossil fuel contributions from winter coal combustion and vehicle emissions in Seoul.

References

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