Drugs have a habit of making their way from our bodies into the environment: they’ve frequently been found in waste water, drinking water, and rivers (not to mention on dollar bills). But they could also be rising into the air, and a new study suggests their aerial concentrations could give scientists a clue to what, exactly, is happening on the ground below. Following up on earlier research showing that cocaine was present in the air above the cities of Taranto and Rome, Italian researchers at the Institute of Atmospheric Pollution Research in Rome took about 60 samples of air in various regions and tested for a number of contaminants, including cocaine, cannabinoids (chemicals found in marijuana), and more common pollutants, like ozone and hydrocarbons. When they looked to see whether there was a correlation between cocaine concentration and addicts’ requests for treatment in particular geographical areas, they found a very strong relationship. Weaker correlations existed between cocaine concentration and police seizures of cocaine and concentration and seizure of all kinds of illicit substances. The team is excited about the possibility of using aerial cocaine concentration to get a sense of drug use levels, a notoriously slippery thing to measure, and possibly other activities that sometimes occur in tandem with drug use, like robberies. However, their approach didn’t turn up any significant correlations between crime-related activities and cannabinoids, which is interesting—what does that mean about the social correlates of marijuana use (or, alternatively, about the fraction of cannabinoids that actually make into the air)? If you’re worried about getting high from the air, it seems unlikely that concentrations are high enough to have an effect. But who knows—that’s a question that has yet to be addressed.