(a) Individual ROS concentrations, C,
and (b)
gross chemical production, P, of individual ROS in
the ELF as a function of ambient PM2.5 concentration. The right axis
in (b) shows the gross chemical production rate of individual ROS
(P′, Table S4).
The solid lines represent a standard PM2.5 composition, and the markers
represent explicit PM2.5 compositions derived from field data (Tables S5–S7). CO2− and CHO2 in (a) are
calculated using acid–base equilibria, as detailed in the Supporting Information, Section S6. In (b), PO2− also includes PHO2. The dotted line in (a) shows the steady-state O3 concentration in the ELF.