MADRID (AP) — Sniff the air in Barcelona or Madrid, scientists say, and you'll inhale not only carbon dioxide but possibly cocaine, too.

Pollution plagues Spanish cities, but a new study reports the air in those two is also laced with drugs — notably cocaine.

The Superior Council of Scientific Investigations, a government institute, says on its website Thursday it also found traces of amphetamines, opiates, cannabinoids and

lysergic acid, a relative of LSD, wafting through those cities.

Researchers say their testing sites were in areas where drug use is likely high. But they said there's no reason for alarm.

"Not even if we lived for a thousand years would we consume the equivalent of a dose of cocaine by breathing this air," scientist Miren Lopez de Alda said.