Story at-a-glance Microplastics are tiny plastic particles less than 5 millimeters in size, found everywhere in the environment, and capable of accumulating in human and animal lung tissues A 2025 study found microplastic particles in every lung sample from 51 bird species, with an average of 221 particles per bird's lungs. These findings suggest similar widespread contamination in humans Previous research has shown that microplastics are present in human lung tissues, with particles from common plastics like polypropylene and polyethylene terephthalate (PET) Microplastics disrupt hormone balance, cause chronic inflammation, create oxidative stress, damage gut health, and even cross the placenta and blood-brain barrier To reduce your microplastic exposure, switch to reusable bags, store food in glass containers, avoid using single-use plastics, choose natural home products, and improve your indoor air quality with an air filter