Volatile contributions to aviation nvPM: a mass spectrometric analysis of nvPM emissions

Abstract

Certification standards for non-volatile particulate matter (nvPM) emissions from aircraft engines have recently been adopted by ICAO as the CAEP10 standard in 2016 and the CAEP11 standard in 2019. The measurements of the nvPM levels are prescribed in ICAO (2019) and SAE documents (2021). The measurement system specifications are designed to minimize the volatile contributions to the measured nvPM quantities. In a series of “certification-like” measurement campaigns that were used to collect data for developing the ICAO nvPM standards, the volatile particulate matter (vPM) contributions to the measured nvPM were quantified. An Aerosol Mass Spectrometer (AMS) in concert with a Cavity Attenuation Phase Shift (CAPS) monitor were used to measure the vPM and nvPM levels, respectively. These vPM contributions are primarily representative of coatings on the nvPM soot particles. Data from a range of engine designs were collected and the relative amounts of vPM to nvPM were ascertained to determine how much the vPM component could affect the nvPM quantification. For the engines evaluated, which span a variety of in‑service engines in the commercial fleet, the vPM contributions are small, averaging 3 % of the nvPM mass value, and were usually relatively independent of engine power condition.