Now billions of toxic air pollution particles can be traced in the hearts of young city dwellers, new research disclosed.
The damage was evidenced even in the cells of a three years old’s critical pumping muscles containing the tiny particles. As per the study, the long-established statistical link between dirty air and heart disease could be due to these iron-rich particles, produced by vehicles and industry.
Scientists said the particle air pollution must be reduced urgently as the abundance of the nanoparticles may lead to a severe public health concern. According to the World Health Organization, 90% and more of the world’s population lives with toxic air, and WHO declared the issue a global “public health emergency.”
There may be some uncertainties in their research which scientists acknowledged, but Prof Barbara Maher of Lancaster University said: “This is a preliminary study in a way, but the findings and implications were too important not to get the information out there.”
Same nanoparticles also found in human brains and were associated with another disease caused by air pollution, and that was Alzheimer that Maher and her colleagues found in 2016.
Maher said she was particularly worried about children. However, all age groups were affected.
“For really young people, the evidence is now of very early-stage damage both in the heart and the brain,” she said. “We have a likely candidate [particle] able to access both organs, with the pathological evidence to show damage is happening.”
When tiny particles air pollution are inhaled, they are transported around the body through the bloodstream and damage not only each organ of the human body but virtually every cell, a recent comprehensive review concluded. Many evidenced harmful effects starting from diabetes to reduced intelligence to increased miscarriages are epidemiological, as it is unethical to conduct dangerous experiments on people. However, one study found air pollution particles in the placentas of women who had given birth in 2018.
It is the first time that the new research established that the iron-rich nanoparticles might cause heart disease. Laboratory tests also validated the fact that tiny particles were a significant component of roadside air pollution, and that they can severely damage human cells.
Maher said: “Putting an abundance of iron-rich nanoparticles right into the sub-cellular components of the heart’s muscle tissue, that’s not where you want them to be sitting. They are inside the mitochondria, which are damaged and appear abnormal. Mitochondria are your energy source, making sure your heart pumps effectively.”
An expert on the air pollution triggered cardiovascular effects, Mark Miller, from the University of Edinburgh, but not part of the research, said: “While there are some uncertainties from the study, it highlights how important it is to better understand the way particles in air pollution may cause harm to different areas of the body.
“More effort is needed to reduce particle emissions from vehicles, especially to remove the number of vehicles on the road by encouraging people to walk and cycle for short journeys.”
The research also reviewed and analyzed the heart tissue collected from 63 young victims of road traffic accidents who died without suffering from chest trauma, and was published in the journal Environmental Research. They had an average age of 25 and lived in Mexico City containing high air pollution.
The two major parts considered for the research were: to know the number of iron-rich nanoparticles present, and to check their location within the tissue and the associated damage. Each gram of dried tissue contained particles between 2bn and 22bn; and among the residents of the Mexico City, their presence was two to 10 times higher than in nine control subjects of the residents of less polluted places.
The medical scientists in the team reported that “exposure to [nanoparticles] appears to be directly associated with early and significant cardiac damage.”
Maher said the results were relevant for all countries: “There is absolutely no reason to expect this would be different in any other city.” Based on previous work, she said, additional contaminants were also likely to be carried by the particles. “We can imagine these nanoparticles come loaded with a toxic mix.”
The iron-rich nanoparticles that are formed as molten droplets from the combustion of fuel cool rapidly into spheres with fused surfaces. These characteristics are present in the particles in the heart tissue, rather than naturally formed small iron-rich magnetite crystals in at least one organ, the brain.
The technique of locating the nanoparticles in the heart tissue is different from the technology required to measure their composition. The scientists first separated the particles from the tissues in determining their structure and magnetic content and then estimated the total number based on the average size and magnetism of the particles.
To confirm the composition of particles in situ within the cells, they would require to use expensive equipment, and Maher said they had not even received any funding for the work. “We are having to do this on a shoestring. It is madness.”