The results recently published in the journal Environmental Geochemistry and Health also indicated that the highest concentrations of all analysed hydrocarbons were found in the smallest particles: in the fraction with grains with a diameter of less than 0.2 mm. And the smaller the particles, the easier it is for them to enter the body.

'The results of our research show that it is the smallest fractions of road dust that pose the greatest health risk, especially in densely populated and intensively urbanized areas. Exceeding the safety thresholds for PAHs in road dust confirms the need for more effective monitoring of pollution in cities', said Sylwia Dytłow, PhD, from the Department of Magnetism of the Institute of Geophysics of the Polish Academy of Sciences, quoted in the information sent by the institute's press office.

The scientist is currently managing a project financed by the Polish National Science Centre, within which she is developing an innovative method for rapid assessment of PAH concentrations in road dust using magnetic parameters.

Road dust - one of the main carriers of harmful substances, including polycyclic aromatic hydrocarbons (PAHs) - is a mixture of particles originating from both natural processes and anthropogenic activity, which are deposited on road surfaces. These pollutants are generated, for example, as a result of fuel combustion, exhaust emissions, tire wear and brake pad friction.

'In Poland, we there still are no comprehensive studies on the spatial distribution of PAHs in road dust. Our project, thanks to a wide measurement database, will enable precise determination of the level of pollution in different parts of the city. The conclusions from this research will be of key importance for improving air quality and protecting public health', the researcher explains.

As she points out, the assessment of the environmental risk of these pollutants requires concentrations of individual PAHs obtained using chemical methods (gas and liquid chromatography). 'These are very accurate, but time- and cost-intensive methods. Therefore, in our project, we are working on linking PAH concentrations with magnetic parameters that can be used as a screening parameter for chemical tests. Magnetic susceptibility has been successfully used as an indicator of heavy metal pollution for at least 20 years, although it has not yet been proven that magnetic susceptibility could also be a useful tool in the case of PAH testing', she says.

For this purpose, scientists from the Institute of Geophysics of the Polish Academy of Sciences examine various granulometric fractions of road dust, i.e. different sizes of its grains, which may have different properties, e.g. magnetic ones, or differ in terms of harmfulness of their impact on human health.

According to the researchers, the method based on magnetic parameters will enable cheaper and less time-consuming monitoring of pollution, which may contribute to better protection of the health of city residents. 'The main goal of our project is to develop tools for faster and cheaper assessment of PAH pollution in road dust. In particular, we want to provide a new tool that will allow for effective monitoring of the level of these substances in cities, where the greatest risk to the health of residents occurs', Sylwia Dytłow explains.

She reminds that long-term exposure to air pollution causes numerous health problems and diseases, such as atherosclerosis, respiratory diseases, including premature mortality.

'Our research has shown that in areas with higher traffic density, such as the very centre of Warsaw, PAH concentrations in the smallest dust fractions exceed the safety thresholds proposed by international organizations such as the Washington State Department of Ecology. Additionally, the calculated risk of cancer for children and adults associated with exposure to road dust indicates a high risk of cancer. The results of our research therefore indicate an urgent need for both scientific activities and government interventions to reduce health risks associated with PAH in urban road dust', Sylwia Dytłow concludes. (PAP)

PAP - Science in Poland, Agnieszka Kliks-Pudlik

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