A recent report in Lancet Planetary Health has shown that when humans are developing in the womb, they can be exposed to the harmful effects of air pollution. Black carbon particles are released by vehicles, power plants that burn coal, and other things that burn fossil fuels. Black carbon makes up a significant proportion of air pollution. Now researchers have determined that black carbon particles can cross the placental barrier and reach organs like the liver, lungs, and brain that are developing in the fetus. The fetal exposure is proportional to how much exposure the mother gets.
This work also confirms and expands on 2019 findings reported in Nature Communications, which showed that black carbon particles can get into the placenta. This study used a technique called white-light generation under femtosecond pulsed illumination to show that black carbon particles can be seen in the developing organs of human fetuses.
"What is even more worrying is that these black carbon particles also get into the developing human brain. This means that it is possible for these nanoparticles to directly interact with control systems within human fetal organs and cells," noted study co-author Professor Paul Fowler of the University of Aberdeen.
An unrelated study recently published in Gut Microbes showed that air pollution can disrupt the infant microbiome. Developing fetuses might carry some gut microbes, but the development of the gut microbiome has been shown to begin immediately at birth, ands potentially earlier. The gut microbiome can have a powerful influence on the well-being and health of an individual, so disrupting this microbial community early on in life could have serious consequences, which could be lasting.
"The microbiome plays a role in nearly every physiological process in the body, and the environment that develops in those first few years of life sticks with you," said first study author Maximilian Bailey, MS, who is currently a medical student at Stanford University.
In this study, fecal samples from 103 infants were assessed along with estimates of exposure to air pollution, which was based on data from the U.S. Environmental Protection Agency's Air Quality System.
Increased exposure to air pollution was linked to a more inflammatory profile of the gut microbiome, which could be contributing to a variety of future adverse health outcomes, the study authors noted.
For example, there was significantly less beneficial Phascolarctobacterium bacteria, which are known to aid in neurodevelopment, lower inflammation, and promote gastrointestinal health. Infants that were exposed to the highest levels of PM10, which can come from wildfires and factories, carried more inflammatory Dialister microbes.
The researchers noted that when possible, people should cook with open windows, purchase air filter systems, and avoid walking near areas with a lot of traffic to reduce their exposure to air pollution.