- PET microplastics remain present in lung tissue for at least 14 days after exposure.
- The combination of microplastics and pollen leads to a stronger inflammatory response than pollen alone.
- The study highlights that plastic actively disrupts the immune system.
Inhaled plastic particles can worsen hay fever. That is the finding of new research from the Medical University of Vienna, published on 29 May 2026 in the scientific journal Journal of Hazardous Materials Advances. The study shows that PET microplastics can amplify the immune response to allergens, raising a troubling question about the consequences of plastic pollution for the health of people who are already vulnerable.
Polyethylene terephthalate (PET) is one of the most widely used plastics in the world. It is used in drinking bottles, food packaging, textiles and medical materials, making it a type of plastic to which many people are exposed on a daily basis.
What the researchers found
The research team, led by Michelle Epstein from the Department of Dermatology at MedUni Vienna, administered PET microplastics to mice via the airways. After a single dose, the particles remained detectable in lung tissue for at least 14 days. During that period, an inflammatory response developed: the number of lymphocytes and eosinophils, immune cells involved in allergic reactions, increased measurably.
Two groups were then compared: mice that received ragweed pollen only, and mice that received both pollen and PET microplastics. Ragweed is a plant whose pollen is a common cause of hay fever. In the combined exposure group, airway inflammation was significantly more severe than in the group that received pollen alone.
In additional experiments, in which PET microplastics were administered alongside other allergens, a disrupted systemic immune response was also measured. The microplastics also influenced the production of antibodies against the allergen. The researchers therefore conclude that PET microplastics do not remain passive in the body, but actively interfere with the immune responses involved in the development and worsening of allergies and inflammation.
What needs to happen
This study is yet another argument for tackling plastic at the source and significantly reducing production. As long as plastic remains the default choice for packaging, clothing and medical materials, exposure will be unavoidable. Plastic Soup Foundation calls on policymakers to apply the precautionary principle and restrict the production of unnecessary plastic. Do not wait for complete scientific certainty. There are enough red flags to make the case for systemic change.
The study "Respirable polyethylene terephthalate microplastics modulate airway inflammation and immune responses in murine allergen co-exposure models" was published in Journal of Hazardous Materials Advances (doi: 10.1016/j.hazadv.2026.101223) and was conducted as part of the EU research project IMPTOX.
