Monitoring Semivolatile Organic Compounds at 200m above ground in rural Netherlands using a Denuder Sampler combined with a Proton-Transfer-Reaction Mass Spectrometer

Abstract

Semivolatile Organic Compounds (SVOCs) are anthropogenically and naturally produced atmospheric compounds which can exist in both the gas and condensed phases. These compounds readily condense on surfaces and are therefore important in the context of organic aerosol formation which ultimately impacts radiative forcing and air quality. Unfortunately, the duality of these particles and their trace amounts make them difficult to investigate, but a new technique has been developed to collect and analyze SVOCs. In this project a Denuder Sampler (DS) is combined with a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS) to facilitate deeper investigation of gas phase SVOCs.This setup provides the means to probe the atmosphere with great precision and it is possible to investigate the relatively unexplored realm of SVOCs. The performance of this setup was tested in a controlled lab setting as well as stationed in the rural Netherlands for field measurements. The setup was stationed at 200m atop the Cabauw Experimental Site for Atmospheric Research (CESAR) from September, 2016 – January, 2017. The full mass spectra revealed over 354 different compounds with charge-to-mass ratios within the range m/z 15-500 Da. An analysis code was created in Python to convert the raw data to reflect what was physically in the atmosphere and to analyze the results. This paper includes an overall review of the performance of the new technique and the types of compounds found in rural Netherlands throughout the course of the field measurements.