That site is near Wiesbad, near a city in eastern Italy better known for smog and black cyanobacteria – the bacteria responsible for a deadly skin infection, Pseudomonas putrefactor.
The researchers said they needed to perform further testing to confirm the source of the chemical in either cloudless or nearly transparent smog.
The World Health Organization has called for information about particular substances to be urgently disseminated globally.
It is also encouraging that the chemical, which taps into a chemical energy source known as naphthalene, is found, said the research.