What Are Microplastics Doing to Our Lungs?

Microplastics are tiny plastic particles that come from the breakdown of larger plastic products. They are now found almost everywhere in the environment — in air, water, soil and even inside the human body. Because plastics are widely used in food packaging, health care products, clothing and consumer goods, exposure to microplastics has become nearly unavoidable.

Scientists are increasingly concerned about how breathing in microplastics may affect lung health.

A review published in Food Bioscience examined how microplastics interact with lung cells and what happens inside the body after inhalation. The lungs are especially vulnerable because they are directly exposed to airborne particles. Once inhaled, microplastics can settle in lung tissue and interact with the cells that line the airways.

“These fragments can irritate lung tissue and trigger inflammatory responses,” said lead investigator Keshav Raj Paudel, Ph.D., M.Sc., a senior researcher at the University of Technology Sydney. “Earlier research on microplastics focused mainly on oceans and human exposure through eating seafood; however, growing evidence suggests that inhalation may be an equally, if not more, significant route.”

Studies suggest that microplastics may trigger oxidative stress. Oxidative stress occurs when harmful molecules called reactive oxygen species (ROS) build up in the body faster than antioxidants can neutralize them. This imbalance can damage cells, proteins and DNA. In the lungs, oxidative stress may impair the body’s ability to repair tissue and may accelerate cellular aging.

Microplastics may also interfere with mitochondria, which are the energy centers of cells. When mitochondria do not function properly, cells cannot produce energy efficiently, increasing the risk of tissue injury and dysfunction.

In addition, microplastics appear to activate inflammatory pathways. Chronic inflammation in the lungs is linked to respiratory diseases such as asthma, chronic obstructive pulmonary disease (COPD) and even lung cancer. By weakening immune responses and disrupting normal lung defenses, microplastics may also increase vulnerability to infections.

Another concern is how microplastics interact with lung surfactant, a substance that helps keep air sacs open and functioning properly. If surfactant activity is impaired, breathing mechanics may be affected, potentially leading to abnormal lung function.

“The lungs are particularly vulnerable to microplastic damage due to their large surface area and limited ability to clear particles, particularly smaller ones that travel deep into the lungs,” explained Paudel. “Lung cancer tumors have been found to contain more microplastics than healthy tissue.”

Microplastics may also carry other toxic substances on their surfaces. Because these particles can bind to pollutants, chemicals or heavy metals, they may act as carriers, delivering additional harmful compounds directly into lung tissue.

The review also noted that as microplastics age in the environment (through sunlight exposure, friction and chemical changes) they may become even more reactive and potentially more harmful when inhaled.

Importantly, investigators mentioned that much of the current evidence comes from laboratory and experimental studies. More research is needed to understand long-term health effects in humans, determine safe exposure levels and clarify how different types of plastic particles affect the lungs.

“Different plastics also have varying degrees of toxicity,” said Paudel. “For example, polystyrene microplastics can stick to the lungs’ protective coating, disrupt air sac function and trigger chemical reactions that may damage lung tissue.”

The team is calling for more human studies, improved exposure modeling and stronger regulatory policies to reduce environmental microplastic pollution. In the meantime, this research highlights the growing importance of environmental health and the need to understand how everyday exposures may influence respiratory disease risk.