Researchers find evidence that early childhood exposure to common air pollutants has long-lasting negative impact on immune system and cardiovascular health.
These effects were noted by observing changes in immune cell activity, expression of immunological genes, and blood pressure measurements. These findings highlight a growing concern over the negative impact of air pollution on health.
Negative Impact Over Short & Long-Term Exposures
The study, led by Stanford-based researcher Mary Prunikci (1), describes the negative impact of exposure to common air pollutants such as wildfire smoke, car exhaust, and ground-level ozone.
The research team monitored changes in school-aged children over the course of a year to estimate how exposure to these pollutants over periods of 1 day, 1 week, and 1, 3, 6, and 12 month periods impacted immunity and heart health.
This cohort study was designed to monitor children living within a specific radius of an accurate air-quality monitoring station over a period of intervals measuring the impact of high air pollution on specific immunological biomarkers.
Of the study’s results, lead author Mary Prunicki had this to say:
“I think this is compelling enough for a pediatrician to say that we have evidence air pollution causes changes in the immune and cardiovascular system associated not only with asthma and respiratory diseases, as has been shown before. It looks like even brief air pollution exposure can actually change the regulation and expression of children’s genes and perhaps alter blood pressure, potentially laying the foundation for increased risk of disease later in life.”
For the first time in an air pollution study, researchers used a novel form of mass spectrometry to perform a detailed analysis on immunological biomarkers. This analysis allowed a much more detailed picture of air pollution’s impact on immune health than previous study has provided.
Among these detailed findings, researchers have showed that exposure to PM2.5 particulate matter, carbon monoxide, and ozone increases methylation of immune-associated genes in a way that can negatively long-term health.
Additionally, these alterations in genetic expression can be passed down to future generations. The study also found that exposure to these common pollutants increased the count of common immune cells associated with increased negative outcomes such as cancer, renal failure, diabetes, and obesity (5).
Kari Nadeau, a senior author on the paper offered this opinion on the importance of the study’s findings:
“This is everyone’s problem, nearly half of Americans and the vast majority of people around the world live in places with unhealthy air. Understanding and mitigating the impacts could save a lot of lives.”
A 2019 report published by the World Health Organization (WHO) found that over 90% of the world’s children under the age of 15 breath air that affects their health negatively (2). In addition, the WHO estimates that in 2016 alone more than 600,000 children in this age group died from respiratory conditions caused by air pollution.
The report highlights scientific understandings that air pollution causes neurodevelopment such that mental and motor functions become negatively affected. The report also highlights a near doubling of estimated effected populations among low and middle-income countries compared to high-income countries.
The report also highlights the fact that indoor pollution from sources such as cooking, cleaning, and biotoxins contribute to negative health outcomes as well. In other words, the air outside is a concern but not the only one.
Types of Air Pollution
The United States Environmental Protection Agency (EPA) maintains defining criteria for several types of common airborne pollutants. These include ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, nitrogen dioxide, and lead. In addition to these macro criteria, certain air pollutant designations like particulate matter can be further described by size.
These further defining criteria describe PM10 matter (dust, pollen, mold) and PM2.5 (VOCs, metallic dusts, Combustion particles). In the case of PM2.5 matter, these compounds can come from many sources and pose a range of possible deleterious risk to health. The estimated PM and air pollution quality of a given U.S. location can be viewed at the AirNow website.
Cardiovascular impact of air pollution
In their 2004 review of existing research relating to the impacts of air pollution on cardiovascular disease, the American Heart Association (AHA) found several alarming connections.
Researchers found exposure to PM2.5 over the course of hours to weeks can cause non-fatal cardiac events, longer-term exposures over months and years increases risk of fatal events and lower life expectancy, and that reducing levels of air pollution resulting in lower mortality rates and risk (3).
Higher-Risk Impact on Children
The impacts of air pollution on immunity and cardiovascular health are much more robust for adults compared with children. A minimal number of existing studies had described the impact of air pollution on specific biomarkers such that inferences about immune and cardiovascular health could be made (4).
Air pollution is an ever present aspect of modern life. As industrialization continues around the globe, impacts on environmental health continue to evolve. Previous research has shown that air pollutants like carbon dioxide, ozone, and common particulate matter can negatively impact health.
This latest study provides much-needed detail regarding specific physiological impacts of air pollution on school-aged children living in high-pollution areas. Insights from this study will allow future researchers to better understand and develop mitigating strategies for the negative impact of air pollution on our collective health.
- Prunicki, Mary, et al. “Air Pollution Exposure is Linked with Methylation of Immunoregulatory Genes, Altered Immune Cell Profiles, and Increased Blood Pressure in Children.” Scientific Reports, vol. 11, no. 1, 2021, pp. 4067-4067.
- World Health Organization (W.H.O.). “Children’s environmental health.” World Health Organization, WHO/CED/PHE/18.01, 2018.
- Brook, Robert D et al. “Particulate matter air pollution and cardiovascular disease: An update to the scientific statement from the American Heart Association.” Circulation 121,21 (2010): 2331-78.
- S. Leonardi et. al. “Immune Biomarkers in Relation to Exposure to Particulate Matter: A Cross-Sectional Survey in 17 Cities of Central Europe.” Inhalation Toxicology, vol. 12, no. S4, 2000, pp. 1-14.
- Hensel, Mathias, et al. “Peripheral Monocytosis as a Predictive Factor for Adverse Outcome in the Emergency Department: Survey Based on a Register Study.” Medicine (Baltimore), 96, no. 28, 2017, pp. e7404-e7404.