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Figure from:Measurements of hydroxyl and hydroperoxy radicals during CalNex‐LA: Model comparisons and radical budgets

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Figure S4: Weekend and weekday diurnal average plots of non-methane VOCs (NMVOCs), NOx, and the ratio of NO./NMVOCs observed at the CalNex-LA site.

Figure 4 S4: Weekend and weekday diurnal average plots of non-methane VOCs (NMVOCs), NOx, and the ratio of NO./NMVOCs observed at the CalNex-LA site.

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Figure S1: OH interference measurements from the CalNex-LA site. Top: Example time period during CalNex-LA of alternating 1-min average measurements of total OH signal (blue) and the interference sig- nal measured after external addition of C3F¢ (red). Bottom: 15 min average points of the calculated OH interference vs. the measured interference. The calculated interference is based on laboratory calibrations and found to be equivalent to 7500 (+1000) x [O03] (ppbv) x [H2O] (%) x LaserPower (mW).
Figure S1: OH interference measurements from the CalNex-LA site. Top: Example time period during CalNex-LA of alternating 1-min average measurements of total OH signal (blue) and the interference sig- nal measured after external addition of C3F¢ (red). Bottom: 15 min average points of the calculated OH interference vs. the measured interference. The calculated interference is based on laboratory calibrations and found to be equivalent to 7500 (+1000) x [O03] (ppbv) x [H2O] (%) x LaserPower (mW).
Figure S2: Correlation of J(O'D) photolysis rates and measured OH concentrations from the CalNex-LA site using a linear fit of all data points (gray). Average values are displayed in red.
Figure S2: Correlation of J(O'D) photolysis rates and measured OH concentrations from the CalNex-LA site using a linear fit of all data points (gray). Average values are displayed in red.
Figure $3: Power-law relationships (Eq.1) plotted from the Rohrer and Berresheim (2006) study along with the CalNex-LA results.
Figure $3: Power-law relationships (Eq.1) plotted from the Rohrer and Berresheim (2006) study along with the CalNex-LA results.
Figure S9: Diurnal average weekend + holiday average (blue) and weekday average (red) HONO imbal- ance (Photolysis of HONO — Gas-phase production of HONO) using measured OH, NO and NOAA IBBCEAS HONO co-located from the top of the gas-phase tower at the CalNex-LA site.
Figure S9: Diurnal average weekend + holiday average (blue) and weekday average (red) HONO imbal- ance (Photolysis of HONO — Gas-phase production of HONO) using measured OH, NO and NOAA IBBCEAS HONO co-located from the top of the gas-phase tower at the CalNex-LA site.
"Number of days and averaging time (italicized) for the radical budget given in parentheses; ®C2 and higher carbonyl photolysis portion of ‘other’ given in parentheses; ‘The | AFRE campaign was carried out in Sep. 1993, but the two modeling analyses presented here focused on different days in the campaign; SHONO mixing ratios were not constrained in the model; *Mechanism includes a heterogeneous HONO source via 2NOz+H20—> HONO+HNOs; ‘'HONO photolysis contributions are net (HONO photolysis — gas-phase HONO production) values; ’California Institute of Technology 3D Air Quality emissions based model coupled with the California Atmospheric Chemistry Mechanism (Griffin et al., 2002, 2004a); "Estimated values from reference publication; ‘Does not account for new ROz formation , thus is a lower limit for this category; Numerical integra- tor based on Gear (1971) coupled with mechanism detailed in Lurmann et al., (1987); ‘Gross OH production from HONO photolysis based on measurements of HONO in the early morning, while daytime HONO concentrations are estimated based on a steady-state expression including 2NOz+H20— HONO+HNOs, direct emission of HONO (only for LOOP/PIPAPO), and HONO loss by photolysis; 'Typical values of OVOCs used from Alicke et al., (2002) to calculate OVOC+hv; "Calculations only based on measured concentrations; "Limited by measurement availability, higher carbonyl photolysis is not included; °Modeling of radical budgets is performed by Mihelcic et al., (2003) but per- cent contribution values are not given nor are they estimated here; PNot provided in the publication, but was indicated that primary HO: initiation routes are those provided; 1Photochemical steady-state model using an updated version of recently used mechanism (McKeen et al., 1997); "Mao et al., (2010) and Ren et al., (2013) have indicated that the OH concentrations in this study should be increased by a factor of ~1.4, therefore the net HONO values here should be considered an upper limit; Breakdown of the ‘other’ category not provided in publication; ‘Mechanism includes homogenous NOz’+Hz0—> HONO+OH reaction; “HCHO not constrained to measurements in the model; ‘Typical Os+alkene provided here for comparison to other campaigns; “Additional routes in the ‘other’ category besides carbonyl photolysis not provided in the reference publication; *Chen et al., (2010) groups HCHO with other carbonyls in the OVOC+hv and states the majority is from HCHO photolysis. Thus total OVOC+hv is given in the HCHO+hv column and other routes besides carbonyl photolysis are given in the ‘other’ column; YValues given are the range of outputs from the 5 mechanisms compared in the HO, budget; 7Values are for the southerly wind direction during the campaign; **Lu et al., (2013) states that 16% of ROx radical initiation is from higher carbonyl photolysis but doesn’t provide the breakdown for the rest of the routes (i.e. O3+alkenes and others); 2®*MEGAPOLI spanned 31 days but the radical budget was performed on campaign average values
"Number of days and averaging time (italicized) for the radical budget given in parentheses; ®C2 and higher carbonyl photolysis portion of ‘other’ given in parentheses; ‘The | AFRE campaign was carried out in Sep. 1993, but the two modeling analyses presented here focused on different days in the campaign; SHONO mixing ratios were not constrained in the model; *Mechanism includes a heterogeneous HONO source via 2NOz+H20—> HONO+HNOs; ‘'HONO photolysis contributions are net (HONO photolysis — gas-phase HONO production) values; ’California Institute of Technology 3D Air Quality emissions based model coupled with the California Atmospheric Chemistry Mechanism (Griffin et al., 2002, 2004a); "Estimated values from reference publication; ‘Does not account for new ROz formation , thus is a lower limit for this category; Numerical integra- tor based on Gear (1971) coupled with mechanism detailed in Lurmann et al., (1987); ‘Gross OH production from HONO photolysis based on measurements of HONO in the early morning, while daytime HONO concentrations are estimated based on a steady-state expression including 2NOz+H20— HONO+HNOs, direct emission of HONO (only for LOOP/PIPAPO), and HONO loss by photolysis; 'Typical values of OVOCs used from Alicke et al., (2002) to calculate OVOC+hv; "Calculations only based on measured concentrations; "Limited by measurement availability, higher carbonyl photolysis is not included; °Modeling of radical budgets is performed by Mihelcic et al., (2003) but per- cent contribution values are not given nor are they estimated here; PNot provided in the publication, but was indicated that primary HO: initiation routes are those provided; 1Photochemical steady-state model using an updated version of recently used mechanism (McKeen et al., 1997); "Mao et al., (2010) and Ren et al., (2013) have indicated that the OH concentrations in this study should be increased by a factor of ~1.4, therefore the net HONO values here should be considered an upper limit; Breakdown of the ‘other’ category not provided in publication; ‘Mechanism includes homogenous NOz’+Hz0—> HONO+OH reaction; “HCHO not constrained to measurements in the model; ‘Typical Os+alkene provided here for comparison to other campaigns; “Additional routes in the ‘other’ category besides carbonyl photolysis not provided in the reference publication; *Chen et al., (2010) groups HCHO with other carbonyls in the OVOC+hv and states the majority is from HCHO photolysis. Thus total OVOC+hv is given in the HCHO+hv column and other routes besides carbonyl photolysis are given in the ‘other’ column; YValues given are the range of outputs from the 5 mechanisms compared in the HO, budget; 7Values are for the southerly wind direction during the campaign; **Lu et al., (2013) states that 16% of ROx radical initiation is from higher carbonyl photolysis but doesn’t provide the breakdown for the rest of the routes (i.e. O3+alkenes and others); 2®*MEGAPOLI spanned 31 days but the radical budget was performed on campaign average values