Fig. 5: Comparison of the average contributions of several major substances or parameters at the mountain and surface sites.

Fractions of particle-phase organic nitrates-to-total nitrate (NO3,org/pNO3), oxygen-to-carbon (O:C), nitrogen-to-carbon (N:C), CHN+, CHON+, fraction of brown carbon (BrC) absorption (bBrC), and absorbing Ångström exponent (AAE, right y axis) for the mountain and surface site during the convective mixing period.