Fig. 3: Microphysical control on predicting quasi-steady state carbon centered radicals (CCR) and reactive oxygen species (ROS) concentration in the atmosphere.
From: Photolytic radical persistence due to anoxia in viscous aerosol particles
a CCR concentration, [CCR], as a function of temperature, T, and relative humidity, RH, in particles is shown. High [CCR] occurred primarily at drier conditions and lower T to a lesser degree. b ROS concentration, [ROS], as a function of the mole ratio between iron(III)-citrate (FeIIICit) and citric acid, Mr, and the photochemical reaction rate, j. The maximum ordinate value, j = 5.23 × 10-2 s-1, corresponds to the photochemical dissociation rate for FeIIICit with a light intensity at the Earth’s surface at 0° zenith. Mr and j values in a are indicated by the circle in b. T and RH values in b are indicated by the cross in a. [CCR] and [ROS] were averaged over the last 30 min for a particle having a radius of 0.5 µm in a 1 h simulation using the photochemical reaction and diffusion (PRAD) model. Dashed colored rectangles indicate the range of values for various field studies held in the southern Great Plains, USA17 (purple), Aksu, China19 (blue), urban centers in Canada20 (white), the Po Valley of Italy21 (green), and Okinawa Island39 (red) detailed in the Supplementary Information.
