Current air pollution regulations focus primarily on the mass of particles of a certain size range in a sample, and this has been used as a marker of their threat to human health.
But these air quality standards do not address the medical implications of the smallest particles , or other attributes that can be harmful, such as their chemical composition .
“Mass is indeed a useful measure, but it may not be sufficient on its own and laboratory research could help establish other more health-related air quality metrics,” said Dr. Konstantina Vasilatou, who directs the Particle and Aerosol Laboratory of the Swiss Federal Institute of Metrology (METAS).
The cleanliness of the air caused by reduced road and air traffic during confinement, together with indications that air pollution may be linked to higher coronavirus death rates , is highlighting the effects of air pollution on the population. Human health.
While we know that air pollution can play an important role in long-term health problems such as respiratory and cardiovascular diseases, cancer, and dementia, some granularity about the exact effects of different types of particles is still missing.
Chemistry
By studying a particular class of airborne pollutants, known as secondary organic aerosols , Dr. Vasilatou aims to assess how their chemistry, as well as their physical properties, can affect the cells of the human respiratory system.
These pollutants are formed when particles from natural and man-made sources, including soot from vehicle engines, factories, or fires, become coated with chemicals formed during the breakdown of so-called volatile organic compounds (VOCs). in the air. It can be paint or solvent fumes, or even the natural chemicals that give pine trees their scent.
These volatile organic compounds are normally oxidized by interactions with ozone, nitrogen oxide, or hydroxyl radicals in the atmosphere, with the help of sunlight. The resulting chemical residues, known as secondary organic matter, are then deposited on the particles or even merge into new ones.
Dr. Vasilatou and her colleagues from the AeroTox consortium have been conducting experiments to assess how pure carbon particles coated with different amounts of secondary organic matter affect lung tissue or sections of the human trachea , to measure their cytotoxicity, that is, how they damage and destroy cells or cause inflammation.
“The more we coat these particles, the greater the cytotoxic effects,” Vasilatou said, adding that the project’s early findings are still being analyzed, but clearly show that the chemistry of the coated particles is involved in the destruction of cells.
Researchers continue to work to understand how the mass or surface of the coated particles can affect cells, in addition to their chemical composition.
Ethical considerations rule out testing in human volunteers, but researchers are using donated tissue and three-dimensional multicellular lung scaffolds, along with novel methods for the interaction between aerosols and cells, to give a more realistic picture of what would happen during inhalation, in rather than simply soaking the cells in liquid with the contaminants.
“We look forward to advising public health policy or helping national health authorities by providing evidence to make more informed decisions,” Vasilatou said.
This type of research could help rethink current air pollution standards, which are typically regulated by the mass concentration of particles less than 10 microns in diameter (PM10) or less than 2.5 microns (PM2.5). . These categories do not adequately address airborne ultrafine particles (less than 100 nanometers) that can be inhaled to the furthest corners of the lungs and, according to some studies, then pass into the bloodstream and are transported throughout the body. These particles are usually found in higher concentrations in areas with a lot of road traffic.
Ultrafina
Some epidemiological research suggests that decreasing particle size can have serious health effects , although there are inconsistent results in exploring associations between ultrafine particles and mortality and hospital admissions.
“It is important to know if these particles are playing this negative role for health, because if they are, then approaches can be introduced that reduce their production in society,” said Professor Frank Kelly, of the environmental research group at the school of Public Health from Imperial College London, UK.
Part of the difficulty in regulating these ultrafine particles is that they are more difficult to measure and control , and require more sophisticated and expensive equipment. It would not be feasible to establish regulatory standards that cannot be effectively monitored, says Kelly.
Kelly supervised a research project on ultrafine particle pollution while at King’s College London, confirming suspicions that road traffic was a major source of ultrafine pollutants in four European cities with different climates and conditions.
But a surprising finding from the Health1UP2 study was the remarkable impact of aircraft emissions on the air quality of the four cities (Barcelona, Helsinki, London and Zurich) even when the airports were located far from the city center. “Many, many miles away we were still seeing these ultrafine particles from aircraft emissions,” said Professor Kelly.
While traffic was the major contributor to urban concentrations of measured atmospheric particles, Health1UP2 research showed that Barcelona experienced a strong seasonal effect on the abundance of ultrafine particles due to the effect of sunlight. This was particularly noticeable in the bright summer months , when sunlight played a major role in the decomposition of gases in the atmosphere and in the formation of new aerosols.
Although the Health1UP2 research did not identify a relationship between detected ultrafine particles and death rates in the four cities, Professor Kelly said it would be useful for future research to analyze the data for any association with hospitalization rates for chronic health conditions. specific.
Even in the absence of new regulations to reduce the production of problem particles, such knowledge can help people recognize the causes and change their behavior and lifestyle to reduce their exposure.
Artículo original
This article was originally published in Horizon, the EU Research and Innovation Magazine
