Drug substances in the air of a New Zealand city

Abstract

Nicotine, caffeine, methamphetamine, and Δ9-tetrahydrocannabinol (THC) were quantified in the total suspended particulate matter of New Zealand's largest city (Auckland), representing the first study of airborne drug concentrations in Oceania. The average airborne concentrations for each drug over the 5-week study were as follows: nicotine (4.91 ± 1 ng m−3), caffeine (16.1 ± 2 pg m−3), methamphetamine (24.8 ± 3 pg m−3), and THC (1.87 ± 0.2 pg m−3). Nicotine and caffeine were higher during weekdays while illicit drugs methamphetamine and THC were higher on weekends, with the lone exception being the weekday sample that overlapped New Year's Eve. Airborne caffeine concentrations correlated with urban pedestrian counts (P = 0.009), demonstrating that atmospheric caffeine concentrations may be an indicator for urban activity. Laboratory contamination of caffeine occurred after the analyst had consumed coffee, highlighting the importance of using laboratory controls when doing trace level analysis. The airborne monitoring of drugs may serve as a complementary technique to wastewater analyses, potentially providing higher resolution spatial data related to locations of drug use, handling, and manufacture. Airborne drug monitoring may also be useful for jurisdictions planning to assess policy performance, such as restrictions on the use and sale of smoked tobacco products in New Zealand.