Decoding the chemistry of polluted air
Every day, people breathe in a complex mix of gases and particles produced by traffic, industry, agriculture and natural events such as forest fires. Together these pollutants shape air quality, human health and the climate. Researchers involved in the EU-funded ATMOS(opens in new window) project are working to better understand what happens to these chemicals once they enter the atmosphere and how that knowledge could help support cleaner air in the future. “We are living in the troposphere, a layer of Earth’s atmosphere about 10 km high,” said María Luisa Senent Díez, senior scientist at the Spanish National Research Council(opens in new window). “The troposphere is our home, we have to keep it clean and healthy.” Running from 2020 until early 2026, ATMOS brought together researchers from Europe, North Africa, China and Chile to study atmospheric pollutants and greenhouse gases. The collaboration combined laboratory experiments, computer modelling and advanced spectroscopy techniques to investigate how gases interact with each other and with particles in the atmosphere.
Tracking harmful pollutants
A major focus of the research was on volatile organic compounds (VOCs)(opens in new window) – gases released from sources ranging from industrial solvents and fuel emissions to household products and vegetation. Once released into the atmosphere, these compounds continue to react and evolve. “These pollutants are produced after natural and human processes, and once they are in the atmosphere, they react to produce secondary species and aerosols,” Senent Díez explained. Some VOCs contribute to the formation of tropospheric ozone(opens in new window), a pollutant that can damage human health and ecosystems. Others help generate highly reactive molecules known as radicals, which drive many chemical reactions in the atmosphere. ATMOS researchers studied these processes in detail, including how pollutants break down under sunlight, how they may contribute to ozone formation and depletion and how they might eventually be captured and removed using new materials. The work also included studies of ketones, aldehydes, alcohols and greenhouse gases such as carbon dioxide.
Understanding climate and air quality
Although ATMOS did not directly measure outdoor pollution, the laboratory work has helped scientists build a more accurate picture of atmospheric chemistry and improve future monitoring tools. “Much work has been done, but much remains to be done because Earth’s atmosphere is a complex system containing many different chemical species,” Senent Díez noted. Greenhouse gases are another important focus. Senent Díez points to increasingly visible signs of climate change, including extreme weather events linked to warming temperatures. “Greenhouse gases such as CO2 are responsible for global warming,” she said.
Training future scientists
The initiative also placed strong emphasis on training young researchers. Nine doctoral students carried out advanced research through ATMOS, with many spending time at partner institutions abroad. For researchers from developing countries, access to specialised European laboratories and equipment was especially valuable. “For students coming from North African countries, visiting European institutions is very relevant because we have tools that do not exist in their countries,” Senent Díez said. International cooperation is central to the work. Alongside European partners from Spain, France, Germany and the United Kingdom, ATMOS includes collaborators from Morocco, Algeria, China and Chile. “To have a clean atmosphere is a human responsibility,” Senent Díez said. “International cooperation is very important.”
