Fig. 5: Variations of PM1 species and OA factors under different pollution stages.
From: Staggered-peak production is a mixed blessing in the control of particulate matter pollution
a Relative contributions and b average mass concentrations of PM1 species and OA factors on clean days (C), average-pollution days (AP), and heavy-pollution days (HP) during the NPhs, SPhs, and NPnhs (As shown in the doughnut plot in the upper right corner, the innermost circle of this plot represents the clean days, the middle circle represents the average-pollution days, and the outermost circle represents the heavy-pollution days).
