Airborne microplastic particle concentrations and characterization in indoor urban microenvironments

Area of Science:

• Environmental Science
• Toxicology
• Public Health

Background:

• Indoor environments are critical as humans spend ~90% of their time indoors.
• Airborne microplastics (MPs) are a growing concern due to potential human inhalation risks.
• Understanding indoor MP concentrations is vital for assessing public health impacts.

Purpose of the Study:

• To quantify airborne microplastic concentrations in diverse indoor urban environments.
• To characterize the size, shape, and polymer types of airborne MPs.
• To evaluate the inhalation risk associated with indoor airborne MPs.

Main Methods:

• Airborne particulate matter was collected using 20 μm pore size nylon filters.
• Samples underwent visual inspection and characterization (color, size).
• Polymer identification was performed using μFTIR analysis; quality control measures were implemented.

Main Results:

• Highest average MP concentrations were observed in buses (17.3 MPs/m³), followed by subways (5.8 MPs/m³), houses (4.8 MPs/m³), and workplaces (4.2 MPs/m³).
• Identified polymers were primarily polyamide (PA, 51%) and polyester (PES, 48%), common in textiles and personal care products.
• Most MPs were fibers (64%) and fragments (78%) below 100 μm, indicating a potential inhalation hazard.

Conclusions:

• Indoor environments, particularly public transport, harbor significant airborne microplastic concentrations.
• The prevalence of small-sized MPs suggests a considerable risk of human inhalation.
• Further research is needed to fully understand the health implications of indoor airborne MPs.