Cities need accurate emission estimates for climate action. We compared five emission inventories over the Greater Tokyo Area using measurements from four sites and an atmospheric transport model. We found that measurements at the four sites show distinct features of the inventories in emission amount and spatial distribution. Site choice is important for evaluating urban emissions. These findings can help improve emission inventories, future urban observations and simulations.

This study presents a new approach to quantify anthropogenic terpene emissions by measuring VOCs during winter, when biogenic emissions are negligible. Measurements in Helsinki showed that although anthropogenic terpenes accounted for less than 1 % of VOC mass, they made a disproportionately large contribution to atmospheric reactivity. The findings highlight the importance of including anthropogenic terpene emissions in urban air quality studies and atmospheric chemistry models.