Wooldridge, P. J.Perring, A. E.Bertram, T. H.Flocke, F. M.Roberts, J.M.Singh, H. B.Huey, L. G.Thornton, J.A.Wolfe, G. M.Murphy, J. G.Fry, J. L.Rollins, A. W.LaFranchi, B. W.Cohen, R.C.2020-09-162020-09-162010-05-12P. J. Wooldridge et al., Total Peroxy Nitrates (ΣPNs) in the atmosphere: the Thermal Dissociation-Laser Induced Fluorescence (TD-LIF) technique and comparisons to speciated PAN measurements, Atmos. Meas. Tech., 3, 593–607, 2010 https://doi.org/10.5194/amt-3-593-2010https://doi.org/10.5194/amt-3-593-2010http://hdl.handle.net/11603/19659Peroxyacetyl nitrate (PAN) and its chemical analogues are increasingly being quantified in the ambient atmosphere by thermal dissociation (TD) followed by detection of either the peroxyacyl radical or the NO₂ product. Here we present details of the technique developed at University of California, Berkeley which detects the sum of all peroxynitrates (ΣPNs) via laser-induced fluorescence (LIF) of the NO2 product. We review the various deployments and compare the Berkeley ΣPNs measurements with the sums of PAN and its homologue species detected individually by other instruments. The observed TD-LIF ΣPNs usually agree to within 10% with the summed individual species, thus arguing against the presence of significant concentrations of unmeasured PAN-type compounds in the atmosphere, as suggested by some photochemical mechanisms. Examples of poorer agreement are attributed to a sampling inlet design that is shown to be inappropriate for high NOₓ conditions. Interferences to the TD-LIF measurements are described along with strategies to minimize their effects.15 pagesen-USThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.Public Domain Mark 1.0This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.Text