Occurrence of cocaine in the air of the World's cities. An emerging problem? A new tool to investigate the social incidence of drugs?

The occurrence of illicit substances in the air was investigated in various world locations and ambient conditions. The analytical procedure optimized for cocaine, methadone and cocaethylene, based upon soxhlet extraction with organic solvent, clean-up through column chromatography, gas chromatographic separation and mass spectrometric detection, allowed the detection of the three compounds at levels as low as approximately 1 pg m(-3) in air samples of approximately 500 m3. Apart from Algiers, Algeria, and Pancevo, Serbia, cocaine was found in all cities investigated and its concentration ranged from picograms to nanograms/cubic meter (e.g., Rome, Italy, 22/97 pg m(-3); Santiago, Chile, 2.2/3.3 ng m(-3)). By contrast, the concentrations of methadone and cocaethylene in the air were always lower than the limit-of-detection allowed by the method. The procedure adopted was unsuitable for measuring cannabinoids and allowed only the identification of cannabinol. It was also poor in limit-of-detection with regards to heroin (35 pg m(-3)), however this compound could be identified in airborne particulates in Oporto, Portugal. Atmospheric concentrations of cocaine appeared to correlate to drug prevalence in the Italian regions investigated.