Airborne microplastics (AMPs) have emerged as a growing environmental and public health concern. These microscopic plastic particles can remain suspended in the atmosphere and may be inhaled by humans, potentially leading to adverse health effects. Despite increasing awareness of microplastic pollution, limited analytical data exists regarding the occurrence, composition, and behavior of airborne microplastics.
To address this challenge, researchers have developed analytical approaches based on Pyrolysis-GC/MS for the identification and quantification of airborne microplastics in atmospheric particulate matter (PM). Before performing detailed quantitative analysis, it is essential to understand the thermal behavior of collected samples. This is where EGA-MS analysis becomes a valuable tool for determining appropriate thermal desorption and pyrolysis conditions.
This article explores a preliminary EGA-MS study conducted on airborne particulate matter and demonstrates how evolved gas analysis supports the development of reliable Pyrolysis-GC/MS methods for airborne microplastic characterization.
Table of Contents
- Introduction to Airborne Microplastics
- Why Airborne Microplastics Matter
- What is EGA-MS?
- Objectives of the Study
- Collection of Atmospheric Particulate Matter
- Experimental Setup
- Instrumentation and Materials
- EGA-MS Measurement Conditions
- Results of EGA-MS Analysis
- Identification of Key Compounds
- Determining Thermal Desorption and Pyrolysis Conditions
- Applications of Airborne Microplastic Analysis
- Benefits of EGA-MS for Environmental Studies
- Conclusion
Introduction to Airborne Microplastics
Microplastics are plastic particles smaller than 5 mm that originate from the degradation of larger plastic products or are intentionally manufactured for industrial applications.
While much attention has focused on marine and freshwater microplastics, airborne microplastics have become an important area of environmental research due to their potential impact on human health.
These particles can originate from:
- Synthetic textiles
- Tire wear
- Packaging materials
- Industrial emissions
- Urban dust
- Construction activities
Once released into the atmosphere, airborne microplastics can travel long distances and become incorporated into particulate matter.
Why Airborne Microplastics Matter
Airborne microplastics may be inhaled and deposited within the respiratory system.
Potential concerns include:
- Respiratory irritation
- Long-term exposure risks
- Environmental transport of pollutants
- Ecosystem contamination
- Human health impacts
To better understand these risks, accurate analytical methods are required to identify and quantify microplastics present in airborne particulate matter.
What is EGA-MS?
Evolved Gas Analysis-Mass Spectrometry (EGA-MS) is a thermal analysis technique that monitors gases released from a sample as temperature increases.
EGA-MS provides valuable information regarding:
- Thermal decomposition behavior
- Volatile organic compounds
- Polymer degradation patterns
- Thermal stability
- Sample composition
The technique is particularly useful for environmental samples because it helps determine suitable thermal desorption and pyrolysis conditions before conducting detailed Pyrolysis-GC/MS analysis.
Objectives of the Study
The primary objective of this study was to establish a reliable analytical method for the qualitative and quantitative analysis of airborne microplastics present in atmospheric particulate matter.
Specific goals included:
- Characterizing thermal behavior of airborne microplastics
- Identifying temperature regions associated with volatile compounds
- Determining suitable thermal desorption temperatures
- Establishing optimal pyrolysis conditions
- Supporting subsequent Pyrolysis-GC/MS analysis
Collection of Atmospheric Particulate Matter
Atmospheric particulate matter was collected on the rooftop of the Pharmaceutical Sciences Building at Tokushima University.
A Multi-Nozzle Cascade Impactor (MCI) sampler connected to a vacuum pump was used to collect airborne particles.
The collection system separated particles into three size fractions:
PM Categories
| Particle Fraction | Description |
| >PM10 | Particles larger than 10 µm |
| PM2.5–10 | Particles between 2.5 and 10 µm |
| PM2.5 | Fine particles smaller than 2.5 µm |
Sampling was conducted during two separate collection periods, producing two environmental samples designated:
- PM-A
- PM-B
Experimental Setup
For EGA-MS measurements, a Multi-Shot Pyrolyzer directly connected to a GC/MS system was utilized.
The collected quartz filters containing airborne particulate matter were processed as follows:
- Quartz filters were punched into 4 mm disks.
- Three filter disks were placed into a sample cup.
- The sample cup was introduced into the pyrolyzer furnace.
- EGA-MS measurements were performed under controlled heating conditions.
This approach enabled direct thermal characterization of particulate matter samples.
Instrumentation and Materials
The following analytical equipment was used:
Instruments
- Multi-Shot Pyrolyzer
- Auto-Shot Sampler
- GC/MS System
- UAD™-2.5N Deactivated Metal Tube
- Vent-Free GC/MS Adapter
- Packed GC Glass Insert
- F-Search MPs Software
Consumables
- Eco-Cup LF
- Quartz Filters
- Airborne Particulate Matter Samples
These tools provided accurate thermal analysis and detection of microplastic-related compounds.
EGA-MS Measurement Conditions
The measurements were performed using the following conditions:
| Parameter | Condition |
| Furnace Temperature | 100–700°C |
| Heating Rate | 20°C/min |
| Furnace Interface Temperature | Auto Mode (300°C max) |
| GC Injector Temperature | 300°C |
| Split Ratio | 1:10 |
| Column Flow Rate | 2 mL/min |
| GC Oven Temperature | 250°C |
| GC/MS Interface Temperature | 250°C |
| MS Scan Range | m/z 29–500 |
| MS Scan Rate | Approx. 0.2 scan/s |
These settings allowed comprehensive evaluation of thermal decomposition behavior.
Results of EGA-MS Analysis
The EGA curves obtained from different particulate matter fractions revealed distinct thermal evolution patterns.
The following signals were identified:
Major Detected Components
| Compound | Characteristic Ion |
| Phthalates | m/z 149 |
| Carbon Dioxide | m/z 44 |
| Nitrogen Monoxide | m/z 30 |
| Sulfur Dioxide | m/z 64 |
These compounds were primarily observed between 100°C and 300°C.
Identification of Key Compounds
Phthalates
Phthalates are common plastic additives used as plasticizers in various polymer products.
Their detection suggests the presence of plastic-related contaminants within airborne particulate matter.
Carbon Dioxide
Carbon dioxide was detected during the lower-temperature desorption stage and is associated with various environmental and organic components.
Nitrogen Monoxide
Nitrogen-containing compounds present in atmospheric particulate matter contributed to the observed NO signal.
Sulfur Dioxide
Sulfur-containing environmental pollutants generated sulfur dioxide during thermal analysis.
These findings demonstrate the complexity of airborne particulate matter and highlight the need for advanced analytical techniques.
Determining Thermal Desorption and Pyrolysis Conditions
One of the key goals of EGA-MS is identifying suitable temperatures for subsequent analysis.
Thermal Desorption Region
Most volatile compounds were released between:
100°C – 300°C
This temperature range is appropriate for thermal desorption analysis.
Polymer Pyrolysis Region
Polymer decomposition peaks appeared above:
400°C
Pyrolysis was essentially completed by:
600°C
Based on these findings, the following analytical conditions were selected for subsequent double-shot analysis:
First Stage (Thermal Desorption)
- 100°C → 300°C
- Heating Rate: 30°C/min
- Hold Time: 3 Minutes
Second Stage (Pyrolysis)
- 600°C
These conditions maximize detection efficiency while minimizing unwanted decomposition.
Applications of Airborne Microplastic Analysis
Accurate characterization of airborne microplastics supports numerous environmental and public health initiatives.
Environmental Monitoring
- Air quality assessment
- Pollution source identification
- Atmospheric transport studies
Public Health Research
- Exposure assessment
- Respiratory risk evaluation
- Long-term health studies
Regulatory Studies
- Environmental compliance
- Pollution monitoring
- Policy development
Scientific Research
- Microplastic distribution studies
- Environmental fate investigations
- Analytical method development
Benefits of EGA-MS for Environmental Studies
EGA-MS offers several advantages when analyzing environmental particulate matter.
Key Benefits
- Minimal sample preparation
- Rapid thermal characterization
- Identification of volatile contaminants
- Determination of pyrolysis temperatures
- Support for quantitative Pyrolysis-GC/MS analysis
- Improved analytical efficiency
These capabilities make EGA-MS an effective screening technique for complex environmental samples.
Conclusion
Airborne microplastics represent an emerging environmental challenge that requires reliable analytical methods for accurate identification and quantification. The preliminary EGA-MS study demonstrated that evolved gas analysis can effectively characterize the thermal behavior of particulate matter samples and identify suitable temperatures for thermal desorption and pyrolysis.
The results showed that volatile compounds such as phthalates, carbon dioxide, nitrogen monoxide, and sulfur dioxide were primarily released below 300°C, while polymer decomposition occurred above 400°C and was completed by 600°C. These findings provide a strong foundation for subsequent quantitative analysis of airborne microplastics using Pyrolysis-GC/MS.
For advanced solutions in Pyrolysis-GC/MS, EGA-MS, and environmental microplastic analysis, Frontier Laboratories SEA offers innovative technologies designed for accurate characterization of environmental pollutants and complex particulate matter samples.
