Fig. 1: Overview of ambient gas-phase and particle-phase amines across the globe.

a Geographical distribution of locations where ambient observations of gas-phase amines (open circles), particle-phase amines (filled circles), or both (open left half and filled right half circles) are reported. The colour of the symbol indicates the type of environment (see legend). b Box-whisker plot of gas-phase concentrations of widely reported amines (Table 1). c Same as (b) but for particle-phase amines (Table 2). The black open square indicates the mean, the horizontal black line indicates the median, the bottom and top of the box represent the 25th and 75th percentiles, and the bottom and top of the whisker represent the 5th and 95th percentiles. The cross symbols indicate all individual data points, with the colour referring to the type of environment. ΣA refers to the sum of particle-phase amines. Details of amine measurement technology, location and time periods are presented in Tables 1 and 2. MMA Monomethylamine, DMA Dimethylamine, TMA Trimethylamine, EA Ethylamine, DEA Diethylamine, TEA Triethylamine, ΣA total mass of aliphatic amines.