Airborne measurements of particulate organic matter by PTR-MS: a pilot study

Abstract

Abstract. We herein report on the first successful airborne deployment of the “CHemical Analysis of AeRosol ONline” (CHARON) particle inlet which allowed us to measure the chemical composition of atmospheric submicrometer particles in real time using a state-of-the-art proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) analyzer. The data were collected aboard the NASA DC-8 Airborne Science Laboratory on 26 June 2018 over California in the frame of NASA’s Student Airborne Research Program (SARP). We show exemplary data collected when the airplane i) shortly encountered a particle plume emanating from a wildfire (Lions Fire) in the Sierra Nevada Mountains, ii) intercepted a particle plume emitted from a petroleum refinery close to Bakersfield, iii) carried out a spatial survey in the boundary layer over the San Joaquin Valley, and iv) performed a vertical profile measurement over the greater Bakersfield area. The most important finding from this pilot study is that the CHARON PTR-ToF-MS system measures fast enough for being deployed on a jet research aircraft. The data collected during 3 to 15 second long plume encounters demonstrate the feasibility of airborne point or small area emission measurements. The fast time response of the analyzer allowed us to generate highly spatially resolved maps (1–2 km in the horizontal, 100 m in the vertical) of atmospheric particle chemical constituents. The chemical information that was extracted from the recorded particle mass spectra includes i) mass concentrations of ammonium, nitrate and total organics, ii) mass concentrations of different classes of organic compounds (CH vs. CHO vs. CHN vs. CHNO compounds; aliphatic vs. monoaromatic vs. polyaromatic compounds), iii) aerosol bulk average (O:C) and (H:C) ratios, iv) mass concentrations of selected marker molecules (e.g., levoglucosan in particles emitted from a wildfire, an alkanolamine in particles emitted from a petroleum refinery), v) wildfire emission ratios (∆total organics/∆CO = 0.054; ∆levoglucosan/∆CO = 7.9 x 10−3, ∆vanillic acid/∆CO = 4.4 x 10−4, ∆retene/∆CO = 1.9 x 10−4; all calculated as peak area ratios, in g g−1). The capability of the CHARON PTR-ToF-MS instrument to chemically characterize submicrometer atmospheric particles in a quantitative manner, at the near-molecular level, and in real time brings a new and unprecedented measurement capability to the airborne atmospheric science community.

Airborne Extractive Electrospray Mass Spectrometry Measurements of the Chemical Composition of Organic Aerosol

“…During one FIREX-AQ research flight, EESI-MS and AMS were flown alongside a CHARON PTR-MS, allowing for an airborne intercomparison of the three instruments. CHARON PTR-MS operates by removing gas-phase organic compounds using a charcoal denuder, concentrating aerosol using an aerodynamic lens, evaporating components of OA using a heated vaporizer at 8 mbar, and detecting those OA components by PTR-MS. More detailed descriptions of the CHARON PTR-MS technique and its airborne operation have been published elsewhere (Piel et al 2019;Eichler et al 2015). CHARON PTR-MS and AMS ground measurement intercomparisons have been carried out previously (Müller et al 2017).…”

“…Airborne measurements of OA concentration and composition have been carried out by: filters for offline analysis (Maria et al 2002;Huebert 2004;Heald et al 2005;Forrister et al 2015); particle-into-liquid sampler (PILS) coupled to a total organic carbon analyzer (Sullivan et al 2006;Duong et al 2011); Aerodyne aerosol mass spectrometer (AMS) (P. F. DeCarlo et al 2008); particle analysis by laser mass spectrometry (PALMS) (Murphy et al 1998;Froyd et al 2019); and chemical analysis of aerosol online with proton-transfer-reaction mass spectrometry (CHARON PTR-MS) (Piel et al 2019). PILS coupled to offline ion chromatography (PILS-IC) (Sullivan et al 2014(Sullivan et al , 2019 and CHARON PTR-MS (Piel et al 2019) have both quantified levoglucosan in biomass burning OA from airborne platforms, with PILS-IC demonstrating a detection limit of 0.1 https://doi.org/10.5194/amt-2020-395 Preprint. Discussion started: 7 October 2020 c Author(s) 2020.…”

Direct detection of condensed particulate polycyclic aromatic hydrocarbons on a molecular composition level at low pg m-3 mass concentrations via proton-transfer-reaction mass-spectrometry

“…Gueneron et al, 2015). With the CHARON particle inlet for PTR-MS (Eichler et al, 2015), this capability is extended to PAHs that are condensed onto particles (Müller et al, 2017;Piel et al, 2019). Side-by-side measurements of CHARON PTR-TOF and high throughput filter samples at the TROPOS operated research station in Melpitz, Germany, have already resulted in good qualitative and quantitative agreements on a 24 h basis (Wisthaler et al, 2020).…”

Comment on ar-2024-11

“…Gueneron et al, 2015). With the CHARON particle inlet for PTR-MS (Eichler et al, 2015), this capability is extended to PAHs that are condensed onto particles (Müller et al, 2017;Piel et al, 2019). Side-by-side measurements of CHARON PTR-TOF and high throughput filter samples at the TROPOS operated research station in Melpitz, Germany, have already resulted in good qualitative and quantitative agreements on a 24 h basis (Wisthaler et al, 2020).…”