Real-time analysis reveals a much higher proportion of hazardous substances in particulate matter than expected

For years, people breathing contaminated air are at a higher risk of developing many illnesses. This is thought to be due to the highly reactive components of particulate matter that affect biological processes within the body. However, researchers at the University of Basel in Switzerland show that these components now disappear within hours, completely underestimating the amounts of previous measurements present.

From chronic respiratory problems to cardiovascular disease, diabetes and dementia, health damage caused by particulate air pollution is extensive and serious. The World Health Organization estimates that more than 6 million deaths per year are caused by increased exposure to particulate matter.

The chemical composition of these small particles in the air is extremely complex, originating from both artificial sources and natural widths. Which particles cause which responses and long-term diseases in the body are the subject of intensive research.

This study focuses on particularly reactive components known to experts as oxygen radicals or reactive oxygen species. These compounds oxidize biomolecules within and on the surfaces of the cells in the respiratory tract, damaging them, and in turn trigger inflammatory reactions that affect the whole body.

Experts previously collected specific problems with filters and analyzed the particles following a delay of days or weeks. “These reactive oxygen species react very quickly with other molecules and need to be measured without delay,” says atmospheric scientist Professor Marcus Scalverler, explaining the ideas behind the work he and his team recently published at Science Advances.

Measure in real time from the air

A team from the Ministry of Environment and Science has developed a new method for measuring particulate matter within seconds. This involves collecting particles directly from the air in the liquid, where they come into contact with various chemicals. Within this solution, oxygen radicals react to produce quantifiable fluorescent signals.

Measurements taken using a new method revealed that 60% to 99% of the oxygen radicals disappear within minutes or hours. Therefore, previous analysis of particulate matter based on filter deposition provided distorted images.

“However, measurement errors in the case of delayed analysis are not constant, so they cannot be extrapolated from previous filter-based analysis,” says Kalberer. The actual proportion of hazardous substances in particulate matter is significantly higher than previously assumed, he says.

According to atmospheric researchers, the main challenge with the new method was to develop measuring instruments that could perform chemical analysis under stable conditions, not only in the laboratory but also during field measurements in a wide range of locations.

Different inflammatory responses vary

Furthermore, further laboratory analysis using epithelial cells from the lungs provided evidence that, in particular, short-lived and highly reactive components of particulate matter have different effects than those of particles analyzed using previous delayed measurements. The short-lived reactive components of the particles caused different inflammatory reactions.

In subsequent steps, more measuring instruments are developed to gain deeper insight into the composition and effectiveness of particulate matter. “If we can measure the proportion of highly reactive and harmful components more accurately and reliably, we can also adopt better protection measures,” explains Kalberer.