File photo shows a general view of the sky above a packed Saint Peter's Square as pilgrims and dignitaries wait for the Pope's funeral, April 8, 2005. Scientists have discovered particles of cocaine and marijuana, as well as caffeine and tobacco, in the air of Italy's capital, they said on Thursday. REUTERS/Dylan Martinez

ROME (Reuters) - Scientists have discovered particles of cocaine and marijuana, as well as caffeine and tobacco, in the air of Italy’s capital, they said on Thursday.

The concentration of drugs was heaviest in the air around Rome’s Sapienza university, though the National Research Council’s Dr. Angelo Cecinato warned against drawing conclusions about students’ recreational habits.

Calling their study “the first in the world to show the presence of particles of cocaine suspended in the atmosphere of the city”, the researchers said they took samples in Rome, the southern city of Taranto and in Algiers in North Africa.

Nicotine and caffeine were detected in all three, “showing how widespread consumption of these substances is and how they remain in the atmosphere”, state-funded CNR said in a statement.

The concentration of cocaine in Rome’s atmosphere was only 0.1 nanogrammes (1 nanogramme is one billionth of a gramme) per cubic metre at its height during winter months, the researchers said. But the conclusions were worrying for public health.

“It is well documented that even small concentrations in the air of these pollutants can seriously damage health,” said Dr. Ivo Allegrini of the CNR’s Institute for Atmospheric Pollution.