Exposure-response associations between chronic exposure to fine particulate matter and risks of hospital admission for major cardiovascular diseases: population based cohort study

Dear Editor

We read the article by Wei et coll with great interest. Recently, it has been reported that microplastics and nanoplastics (MNPs) in atherosclerotic plaques are associated with rupture and subsequent thrombotic events leading to stroke, myocardial infarction, or death (1).

Plastic pollution has become a major environmental concern in recent years, with microplastics and nanoplastics (MNPs) being identified as a particularly troubling form of pollution (2). These tiny plastic particles can be found in the atmosphere, contaminating our food, water, and the air we inhale. A 2021 study by a team of scientists estimated that people in five Chinese megacities inhale 1-2 million MNPs annually, indicating that air exposure is the most significant and concerning route of MNP exposure (3).

While plastic polymers are often considered to be chemically inactive, they can still impact biological processes through their physical presence alone. MNPs, however, may also contain or come in contact with biologically active chemicals, posing additional risks to human and environmental health. Once released into the environment, MNPs can attract and accumulate a variety of other contaminants. Due to their physical properties, such as hydrophobicity and a large surface area in relation to their volume, MNPs can act as sponges for toxic metals, polycyclic aromatic hydrocarbons, and other hazardous chemicals. It means that MNPs can serve as carriers for these pollutants, potentially increasing their bioavailability and facilitating their uptake by living organisms.

In addition to their potential to carry and release hazardous chemicals, the ubiquity of MNPs raises concerns about their contribution to air pollution. It is hypothesised that in polluted areas, an unknown amount of MNPs contamination can contribute to the mass of PM2.5 and the number of its ultrafine components. If this hypothesis is confirmed, it could have significant implications for air quality management as the use of plastics continues to increase globally. It could mean that even as efforts are made to reduce other sources of air pollution, the prevalence of plastics could counteract these measures, leading to a lack of significant reduction in PM2.5 levels.

In light of the growing body of evidence on the presence and potential impacts of MNPs in the atmosphere, it is clear that urgent action is needed to address this issue. Efforts to reduce the use of single-use plastics and improve waste management practices are crucial to preventing further contamination of the environment with MNPs. Additionally, further research is needed to better understand the sources, fate, and impacts of MNPs in the atmosphere, as well as the development of mitigation strategies to minimize their environmental and human health risks.

1. Marfella R, Prattichizzo F, Sardu C, Fulgenzi G, Graciotti L, et al. Microplastics and Nanoplastics in Atheromas and Cardiovascular Events. N Engl J Med. 2024 Mar 7;390(10):900-910. doi: 10.1056/NEJMoa2309822. PMID: 38446676.
2. Nicole W. An Ill Wind? Growing Recognition of Airborne Nano- and Microplastic Exposures. Environ Health Perspect. 2023 Apr;131(4):42001. doi: 10.1289/EHP12662. Epub 2023 Apr 28. PMID: 37116008; PMCID: PMC10146709.
3. Zhu X, Huang W, Fang M, Liao Z, Wang Y, Xu L, et al. 2021. Airborne microplastic concentrations in five megacities of Northern and southeast China. Environ Sci Technol 55(19):12871–12881, PMID: 34559513, https://doi.org/10.1021/acs.est.1c03618.