Fig. 2: Experimental results on solutions in the dynamic chamber.
From: Photodissociation of particulate nitrate as a source of daytime tropospheric Cl2
A Time series of 1-min average mixing ratios of Cl2, HONO, and NOx. The liquid solution samples (pH = 1.9) were illuminated at t = 0. The solid red line shows the time at which 300–800 nm filter was used, the red dashed line indicates the time at which AM1.5 filter was used, and the red point line indicates the time at which the xenon lamp was turned off. The left inset: scatter plot of the raw CIMS signal of Cl2 at mass 199 atomic mass unit (amu) (I35Cl37Cl−; I37Cl35Cl−)) versus 197 amu (I35Cl35Cl−) with 1-min average from t = −60 to t = 580 min. The right inset: the scanned mass spectra from 196 amu to 200 amu at t = 387 min. The continuous increase of Cl2 may be due to the higher concentration of ions and acidity in the solution due to the evaporation of water from the solution. B Time series of 1-min average Cl2, NO, and NO2. The liquid solution samples (pH = 2.0) were illuminated at t = 0. The solid black line shows the time at which 10 μl OH scavenger, TBA, was added, the black dashed line indicates the time at which 10 μl DI water was added, the black point line indicates the time at which 10 μl nitrite was added, and the red point line indicates the time at which the xenon lamp was turned off. C The production rate of Cl2 as a function of initial solution pH (pH = 1.9; 2.0; 2.3; 2.9; 3.3; 3.9; 6.8) at the illumination time of 500 min. The error bars in the plot (C) represent the estimated uncertainty in Cl2 and pH measurement. Experimental conditions: 75−83% RH, 298 K in air and one 4 ml liquid solution containing 1 M NaCl + 1 M NaNO3.
