The relative importance of different INP types in the atmosphere will depend on both the 𝑛 𝑠 (𝑇)values (e.g. Figure ) and their atmospheric concentrations. For most conditions in the atmosphere, the concentrations of microplastics are likely far less than the concentrations of mineral dust particles (see Aeschlimann et al. and references therein). Regions where microplastic INPs will be important will be limited to regions where microplastic concentrations are very high or when concentrations of mineral dust particles are low, such as over the Southern Ocean. The concentrations of microplastics in the atmosphere may also increase in the future as their atmospheric sources increase. The 𝑛 𝑠 (𝑇)-values included here provide information for calculating the relative importance of microplastic INPs in the atmosphere, now and in the future.