Completely Cryogen-free Monitoring of PAMS Ozone Precursors, TO-15 Air Toxics and OVOCs in Ambient Air in a Single Run

Air Methods & Monitoring
Oral Presentation

Presented by J. Mayser
Prepared by

Contact Information: [email protected]; 626-386-1125


ABSTRACT

Many of the Volatile Organic Compounds (VOCs) in ambient air have impacts on human health, air quality and climate change. There have been specific standard methods and regulations require routine monitoring of subsets of these compounds using different instrument setups, e.g. TO-15 for air toxics requires GC-MS, PAMS for ozone precursors uses GC-FID and ketones and aldehydes are usually sampled with DNPH cartridges and analyzed by HPLC. This work investigates to harmonize all these different methods to allow efficient analysis of all these compounds using a single TD-GC-FID/MS system in one run. The setup includes a cryogen-free pre-concentrator CIA Advantage-xr and a water management device Kori-xr coupled to a dual-column/Deans switch, which are connected to FID and quadruple MS detector respectively. Experiments using online and canister sampling method were carried out to evaluate the performance of this system for the combined list of PAMS ozone precursors, TO-15 air toxics and polars in high-humidity environments. It is demonstrated to produce data that satisfies the performance criteria for related standard methods, for very volatile C2 hydrocarbons, oxygenated polar VOCs such as acrolein and ethanol, and the less volatile air toxics such as naphthalene, even at 100% relative humidity. Whilst all the performance criteria for the methods in question are met in this study, to further extend the system sensitivity the mass spectrometer could be operated in selected ion monitoring (SIM) mode to improve sensitivity and reduce MDL values by up to an order of magnitude.