Air pollution has long been a fact of life in Spanish cities, but scientists now say that it is not just smog that chokes people as they walk to work or stroll through the park.

A new study has found the air in Madrid and Barcelona is also laced with at least five drugs – most prominently cocaine.

The Superior Council of Scientific Investigations, a government institute, said on its website that in addition to cocaine, it found trace amounts of amphetamines, opiates, cannabinoids and lysergic acid -a relative of LSD – in air-quality control stations in the cities.
[…]
In Madrid the test site was close to a ruined building believed to be frequented by drug dealers. And in both Madrid and Barcelona, the studies were carried out close to universities.

The group also said that the study showed higher concentrations of the components on weekends, suggesting that drug consumption was up in these periods.