Ultrafine particles (UFPs) -smaller than 100 nanometres and invisible to the naked eye – contribute substantially to illness and mortality worldwide, according to the finding of an international study led by researchers at the Max Planck Institute for Chemistry in Mainz and The Cyprus Institute, with cardiologists from Mainz University Medical Center among the co-authors.
The researchers estimate that around 1.99 million deaths per year worldwide are attributable to exposure to ultrafine particles.
That accounts for about five percent of all deaths from non-communicable diseases. Roughly half of these are due to cardiovascular disease. The researchers therefore advocate for binding limit values. The study appears in the journal Cardiovascular Research.
Unlike fine particulate matter (PM2.5), which is subject to legal limit values in the EU and the US, ultrafine particles remain unregulated. Although they contribute little to particulate mass, their small size gives them a very large surface area relative to their mass, allowing them to penetrate deep into the lungs, bypass respiratory defences, and reach the bloodstream and, via the olfactory pathway through the nose, the brain directly. This makes them fundamentally different from larger particulate matter.
According to the researchers’ analysis, ultrafine particles in polluted regions consist mainly of black and organic carbon – typical combustion products. Globally, around 75 percent of exposure originates from fossil fuels, rising to over 90 percent in high-income countries; in lower-income countries, domestic wood burning also plays a significant role.
The Mainz study also shows that an annual limit value of 5,000 particles per cubic centimetre could reduce global excess mortality from ultrafine particles by around 45 percent. The authors therefore call for a consistent reduction of combustion emissions in cities – particularly from traffic, industry and energy production – accelerated expansion of non-fossil energy sources, and the inclusion of ultrafine particles in routine air quality monitoring to better capture their long-term health impact.
Prof. Dr. Jos Lelieveld, Director emeritus at the Max Planck Institute for Chemistry in Mainz and the Cyprus Institute and lead author of the study said that “ultrafine particles are literally a blind spot in air quality policy: they are not covered by any regulation, even though they are ubiquitous in our cities”.
With our data, he noted, ‘we can for the first time show worldwide where exposure is highest and which sources are responsible – above all combustion in traffic, industry and energy production. This gives policymakers a concrete tool to take targeted action”.
CNA/EC/EPH/2026S, CYPRUS NEWS AGENCY