The principle, technical details, and performance of the long path extinction spectrometer (LOPES), a new folded-path extinction cell with a spectral range from the mid-UV (200 nm) to the near infrared (1015 nm), is presented. Using nonabsorbing glass beads the measured extinction spectrum of LOPES was validated by Mie calculations and was compared with scattering coefficients in the visible measured by a three-color integrating nephelometer (TSI, mod. 3563). For absorbing aerosols (here soot and biomass burning aerosol with single-scattering albedos of about 0.2 and 0.74 at 550 nm), LOPES was combined with a TSI 3563 nephelometer to determine the wavelength-dependent absorption coefficients from the difference of the extinction and scattering coefficients. These absorption coefficients were found to agree with the measurements by two state-of-the-art absorption techniques, the multiangle absorption photometry (MAAP) and photoacoustic spectrometry (PAS), which measure the absorption coefficient at the single wavelength of 532 nm and 670 nm, respectively. Finally, based on a comprehensive analysis of the TSI 3563 nephelometer errors and their propagation into the determination of the absorption coefficients from the LOPES and nephelometer data, we discuss implications for improving in situ measurements of the optical properties of atmospheric aerosols.

An overview of the goals and achievements of the European PartEmis project (Measurement and prediction of emissions of aerosols and gaseous precursors from gas turbine engines) is presented. PartEmis was focussed on the characterisation and quantification of exhaust emissions from a gas turbine engine. The engine was composed of a combustor and a unit to simulate a 3-shaft turbine section (so-called Hot End Simulator; HES). A comprehensive suite of aerosol, gas and chemi-ion measurements were conducted under different, i) combustor and HES operating conditions, ii) fuel sulphur concentrations. Measured aerosol properties were mass and number concentration, size distribution, mixing state, thermal stability of internally mixed particles, hygroscopicity, cloud condensation nuclei (CCN) activation potential, and chemical composition. Furthermore, chemi-ions, non-methane volatile organic compounds (NMVOCs) and OH were monitored. The combustor operation conditions corresponded to modern and older engine gas path temperatures at cruise altitude, with fuel sulphur contents (FSC) of 0.05, 0.41, and 1.270 g kg −1. The combustor behaved like a typical aircraft engine combustor with respect to thermodynamic data and main emissions, which suggests that the PartEmis database may be applicable to contemporary aircraft engines. The conclusions drawn from the PartEmis experiment are discussed separately for combustion particles, ultrafine particles, sulphate-containing species and chemi-ions, particle hygrioscopic growth and CCN activation, gaseous organic fraction, and emission properties.

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