Seasonal variations in ambient psychotropic drugs may tell us, predictably, how [sad] we are.

Monthly average marijuana levels in urban air [ScienceDirect]

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Italy's Institute of Atmospheric Pollution Research just published a report that measured psychotropic drugs (including cocaine, nicotine, cannabinoids, and caffeine) in the air in eight major cities: Palermo, Rome, Bologna, Florence, Turin, Milan, Verona, and Naples. The year-long study was part of the Ariadrugs Project that began in 2006 after cocaine was detected in Roman air. But now they've quantified multiple drugs in multiple cities with intent to use the data to inform public health and legal policy.

The levels are low -- not enough to acutely waste anyone -- but enough that we can detect temporal variations that tell us about usage habits. Marijuana and caffeine levels were much higher in the winter than the summer. The suggestion is that it's related to the same factors implicated in seasonal affective disorder, among others.

This can't be unique to Italy. New York? New York, New York, just think of the cocaine in New York. Maybe contributing to why everyone hearts it? "There's just something about it."

And then LA, all socked in under that blanket of air pollution and self-loathing. Let's get some numbers, EPA.