"HELIOS/SICRIT/Mass Spectrometry for Analysis of Aerosols in Engine Exhaust"
Klemens M. Thaler1 , Lorenza Gilardi1 , Markus Weber1 , Andreas Vohburger1 , Zisimos Toumasatos2 , Anastasios Kontses2 , Zissis Samaras2 , Joni Kalliokoski3 , Pauli Simonen3 , Hilkka Timonen4 , Minna Aurela4 , Sanna Saarikoski4 , Sampsa Martikainen3 , Panu Karjalainen3 , Miikka Dal Maso3 , Jorma Keskinen3 , Reinhard Niessner1 , Genny A. Pang1 , Christoph Haisch1*
Aerosol Science and Technology (2021)
Abstract
Current legislations typically characterize systems of aerosols, such as from vehicle exhaust, primarily by number concentration and size distributions. While potential health threats have a dependence on the particle size, the chemical composition of particles, including the volatile and semi-volatile components adsorbed onto nonvolatile particle cores present at roadside and urban settings, is important in understanding the impact of exhaust particles on health. To date, the only tools suitable for an online indepth chemical aerosol characterization are aerosol mass spectrometers, which are typically composed of complex and cost intensive instrumentation. We present a new analytical system, which combines a novel inexpensive infrared-radiation-based evaporation system (HELIOS) with a commercially available highly efficient atmospheric ionization source (SICRIT) connected to a rather low-price iontrap mass spectrometer. Our inexpensive, robust and mobile aerosol characterization HELIOS/SICRIT/Mass Spectrometry system enables highly sensitive chemical analysis of particleassociated volatile substances. We validate the HELIOS/SICRIT/Mass Spectrometry system in laboratory experiments with coated particles generated under controlled conditions, and show that the system is capable of identification of combustion-generated polyaromatic hydrocarbons and relative quantification of individual chemical species adsorbed on particle surfaces. We then employ our system to analyze real-world vehicle engine exhaust aerosol and show through time-resolved measurements with high time resolution (<10s) that the chemical composition of the particles changes during different parts of an engine test cycle.