Measurements of aerosol optical properties in central Tokyo during summertime using cavity ring-down spectroscopy: Comparison with conventional techniques

Sources of Error and Uncertainty in the Use of Cavity Ring Down Spectroscopy to Measure Aerosol Optical Properties

“…The experimental system used in this work consists of the same components as the majority of those to be found in the literature (Bulatov et al 2002(Bulatov et al , 2006Riziq et al 2007;Beaver et al 2008Beaver et al , 2010Dinar et al 2008;Freedman et al 2009;Lang-Yona et al 2009Radney et al 2009;Adler et al 2010;Nakayama et al 2010) and has been described in detail in previous publications (Miles et al 2010a(Miles et al , 2010b. Briefly, particles were generated from an aqueous suspension/solution of the aerosol medium (polystyrene beads or sodium chloride) using a constant output atomizer (TSI Model 3076), before being passed through a Nafion dryer (Perma Pure PD-100T-12SS, http://www.permapure.com/) to remove residual water.…”

“…This highlights an important issue often neglected in publication of A-CRDS data, where the length of the cavity physically occupied by aerosol is frequently either omitted or stated without any reference as to whether it has been confirmed experimentally (Bulatov et al 2006;Garland et al 2007;Beaver et al 2008Beaver et al , 2010Thompson et al 2008;Freedman et al 2009;Baynard et al 2007;Riziq et al 2007;Spindler et al 2007;Dinar et al 2008;Riziq et al 2008;Khalizov et al 2009;Radney et al 2009;Xue et al 2009;Nakayama et al 2010). As the above discussion clearly shows, any uncertainty in the length of the cavity occupied by aerosol has a large impact on the values of the extinction efficiency retrieved by experiment and consequently on the refractive index returned by the fitting process.…”

“…To better constrain the length of the cavity occupied by aerosol, a number of instruments use apertures to separate the mirrors from the rest of the RDC, creating a small volume into which a purge flow of particle-free gas is introduced (Thompson et al 2003(Thompson et al , 2008Pettersson et al 2004;Moosmuller et al 2005;Baynard et al 2007;Radney et al 2009;Nakayama et al 2010). The aerosol sample length is then assumed to be given by the distance between the apertures.…”

“…A-CRDS is now routinely used in laboratory (Sappey et al 1998;Vander Wal and Ticich 1999;Smith and Atkinson 2001;Bulatov et al 2002Bulatov et al , 2003Bulatov et al , 2006Strawa et al 2003;Pettersson et al 2004;Baynard et al 2006;Garland et al 2007;Riziq et al 2007;Rudić et al 2007;Dinar et al 2008;Riziq et al 2008;Butler et al 2009;Freedman et al 2009;Khalizov et al 2009;Lang-Yona et al 2009Radney et al 2009;Xue et al 2009;Adler et al 2010;Hasenkopf et al 2010;Miles et al 2010aMiles et al , 2010b and field studies (Thompson et al 2002(Thompson et al , 2003Strawa et al 2006;Garland et al 2008;Nakayama et al 2010) to measure extinction by both aerosol ensembles (Vander Wal and Ticich 1999;Thompson et al 2002Thompson et al , 2003Thompson et al , 2008Strawa et al 2003;Pettersson et al 2004;Baynard et al 2006Baynard et al , 2007Garland et al 2007;Riziq et al 2007;Beaver et al 2008;…”

Wavelength Dependence of Refractive Index of Secondary Organic Aerosols Generated during the Ozonolysis and Photooxidation of α-Pinene

“…The b sca (532 nm) data obtained by the PASS-3 was not used in this study because a strong particle size dependence of the calibration factors was found. A detailed description of the CRDS and PASS-3 has been previously reported (Nakayama et al 2010a(Nakayama et al , 2010b(Nakayama et al , 2012. The chemical properties of the aerosols were also measured using a high resolution time-of-flight aerosol mass spectrometer (Aerodyne Research, H-ToF-AMS) in the V-mode (Drewnick et al 2005).…”