3506B24 Final Report
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Particle Phase
- Calculation of ambient concentrations A denuder efficiency Φn,tot is calculated for all acidic species from  and  ,
which is taken into account only for the quantification of light organic acid concentrations (acetic, formic, and oxalic acids); for all other species, incl. NH3, it is assumed to be one. If the concentration on denuder 2, cn(D2), is lower than the denuder blank concentration, cn(D2) is assumed to be the blank, leading to an efficiency of 1. The concentration of gaseous species n (with the exception of HNO3 and HONO) is then 
where cn,ion(D1/D2/DB) is the concentration of species n from Denuder 1, 2, blank, respectively, and Mn is the mass correction factor =  ; with molar mass of gaseous/conjugated ionic species. For HNO3 and HONO, due to artifact reactions of adsorbed NO2, the concentrations are derived from:
All particulate concentrations incl. mass, are derived from the Teflon filters. If possible, gravimetric mass is determined as average from both channels 1 and 2 Teflon filters. The filter weights are monitored during several days of clean room exposure and desiccation, minimizing the condensed water vapor artifact in form of hydrates. The species Na+, K+, Ca2+, SO42-, and Cl-are considered non-volatile and calculated as 
where cn,ion(T/TB) are the concentrations of species n from Teflon filter/blank, respectively. The species NH4+, NO3-, acetate, formate, and oxalate, are considered semi-volatile and derived from Download 11.49 Mb. Share with your friends:
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