Chemical compounds from Barcelona traffic found in Montseny Natural Park

Some chemical pollutants from road traffic and transported by sea breezes can alter climatic and ecological aspects, even in protected areas, according to a study by authors from CREAF and IDAEA-CSIC, among others.

A study by CREAF and the Institute of Environmental Diagnosis and Water Studies (IDAEA-CSIC) reveals that volatile organic compounds of human origin are found in the Montseny Natural Park. These compounds originate in Barcelona and are transported by sea breezes to Montseny, 50 kilometres from the city. Volatile organic compounds come from different sources and although the majority are of natural origin, a strong presence of compounds of anthropogenic origin has been found, specifically those derived from the burning of fuels.

"Volatile organic compounds are chemical substances released by plants, fungi, bacteria or animals to communicate, and they play an essential role in climate and water regulation," explains Ana M. Yáñez, lead author of the study and researcher at IDAEA-CSIC. "But these molecules can also be emitted in the form of pollution by human action and cause naturally occurring climatic and ecological relationships to be altered". The research, published in Atmospheric Environment, sampled the air located one and a half metres above the ground in Montseny in three periods between June and November 2019. Iolanda Filella and Josep Peñuelas, both CSIC researchers at CREAF, also collaborated in the research.

The results indicate that in Montseny we found COVs coming from four sources of emissions: those of photochemical production (formed by chemical reactions in the atmosphere), those of biogenic origin (emitted by plants, fungi and animals), those coming from traffic and a mixture of those emitted by plants and those coming from the nearest roads, such as the AP-7.

The study reveals the concentration of these molecules coming from Barcelona and how this pollution mixes with the volatile organic compounds naturally emitted by the Montseny forests. This phenomenon modifies atmospheric chemistry and favours the production of ozone and aerosols. "With this research we can say that air masses from plant sources interact with those from human activities, which changes the atmospheric chemistry, causing people to breathe in this pollution. Although we don't know how this affects human health, fauna or flora, in future research we will be able to see the negative impact of human activity in protected areas," Ana M. Yáñez concludes.

Reference article:

Ana María Yáñez Serrano, Albert Bach, David Bartolomé-Català, Vassileios Matthaios, Roger Seco, Joan Llusià, Iolanda Fillela, Josep Peñuelas. Dynamics of volatile organic compounds in a western Mediterranean oak forest. Atmospheric Environment. 2021. 257, 118447. DOI: 10.1016/j.atmosenv.2021.118447