Our Breath, Our Homes, Our Cars: Ubiquitous Exposure Pathways

Author

Sam Garcia
October 27, 2025

Our daily environments are rife with microplastics. A groundbreaking study published in PLOS One on July 30, 2025, identified car cabins as significant microplastic hotspots, containing a median of 2,238 microplastic particles per cubic meter (MPs/m³)—four times higher than residential air. These concentrations are due to the enclosed nature of vehicles, the heavy use of synthetic materials in dashboards and upholstery, and limited ventilation. An estimated adult may inhale up to 68,000 microplastic particles daily from indoor environments, with over 90% of these particles small enough (1-10 µm) to penetrate deep into the lungs. This inhalation exposure is linked to increased risks of lung inflammation, chronic bronchitis, oxidative stress, and impaired lung function, exacerbating conditions like asthma or COPD.

Homes are not exempt. A University of Birmingham study published in Emerging Contaminants in September 2025, revealed that most indoor microplastics in settled dust originate from synthetic fibers and fragments shed from clothing, carpets, and furniture, with polypropylene (PP) and polyethylene terephthalate (PET) being the most abundant. Humans are exposed through inhalation and inadvertent ingestion of dust.

Breathing in these microplastics poses significant health risks. Experts warn that prolonged exposure can increase the risk of respiratory illnesses, including lung inflammation and chronic bronchitis. Microplastics are capable of penetrating deep into lung tissues, reaching the alveoli, which can trigger an inflammatory response, induce oxidative stress, and impair lung function. This can exacerbate existing pulmonary conditions like asthma or chronic obstructive pulmonary disease (COPD). Furthermore, some research suggests a link between airborne microplastics, particularly those from vehicle tire wear, and an increased risk of lung cancer.

Children, especially toddlers, face disproportionately high exposure. Their estimated daily ingestion is 9.7 MP/kg Bw/day, significantly higher than adults' 0.8 MP/kg Bw/day. This is largely attributed to behaviors like crawling on floors where microplastics accumulate, frequent hand-to-mouth activity, and chewing on plastic toys. Their incompletely developed immune and nervous systems make them particularly vulnerable to potential adverse health effects, with studies detecting 10 to 20 times higher microplastic concentrations in infant feces compared to adults.

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