Agence France-Presse reports that Spanish scientists have detected the presence of cocaine in the air of Madrid and Barcelona by using a new technique for the first time.

The scientists looked for 17 components in five different types of illegal drugs — cocaine, amphetamines, opiates, cannabinoids (marijuana byproducts) and lysergic acid (LSD).

The results revealed cocaine is the predominant drug in the air of the two cities, the CSIC research institute said Wednesday.

It was found in concentrations of 29 to 850 picograms per cubic meter of air. A picogram is one trillionth of a gram.

The study is the result of the first use of a new method for the detection of drugs in the air, adapted specifically for the researchers, who are to publish their results in the review Analytical Chemistry.

"Heroin was also found in detectable levels in the samples taken in Madrid, but not in those from Barcelona," the CSIC said.

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