Air pollution has long been a fact of life in Spanish cities, but scientists now say 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 scientific institute, said on its Web site Thursday that in addition to cocaine, they found trace amounts of amphetamines, opiates, cannabinoids and lysergic acid -a relative of LSD - in two air-quality control stations, one in each city. The group said the findings would be published in the US journal Analytical Chemistry. Despite the findings, the council said there was 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 in a statement.