Conference Agenda

Mobile measurements of particles containing metals and trace elements are needed to understand the emissions and spatial distributions of these pollutants, which are strongly implicated in adverse aerosol health effects. The recently developed Microwave-Induced Plasma Time-of-Flight Mass Spectrometer (mipTOF) is the first instrument providing the requisite combination of time resolution, sensitivity, and quantitative capability to enable such studies. We present the first mobile field deployment of the mipTOF, conducted during Jan.-Feb. 2025 in central Switzerland. The mipTOF successfully characterizes diverse sources, including train and tram emissions, vehicular brake wear, a quarry, and particulate lead.

We showcase a novel MS, the Thermal Desorption Multi-scheme IONization inlet Orbitrap (TD-MION-Orbitrap), for analyzing filters from a boreal forest site. The filters captured condensing vapors, such as sulfuric, iodic, methanesulfonic, and malonic acids, and highly oxygenated organic molecules (HOMs). The timeseries were compared to online measurements from a MION-APi-TOF at the same location, both boasting a nitrate (NO3-) source for chemical ionization. The filter-desorbed compounds matched the online observations by 51% and the signal intensities acquired were comparable in both methodologies. These results provide support for the use of filters in the study of condensing vapors in various environments.

We report on the development and characterization of a new trace-element mass spectrometer for the direct and real-time quantitative analysis of metals in air. The microwave-induced plasma time-of-flight mass spectrometer (mipTOF) features a nitrogen-sustained MICAP high-power plasma source that can be used to directly vaporize, atomize, and ionize nano-to-micron-sized particles from the ambient air. The mipTOF is a fieldable instrument that delivers detection limits from 0.1-5 ng/m³ for almost all elements per 10-second analysis. We will discuss instrument design, performance, calibration strategies, and both stationary and mobile applications of the mipTOF instrument.

We present results on limonene oxidation using the new Bipolar FUSION PTR-TOF for detection of volatile oxidation products and formed SOA constituents that we produced in a novel laminar flow oxidation reactor. The Bipolar FUSION PTR-TOF provides multiple selective reagent ions, the positive (H3O+, NH4+, NO+, O2+) and the new negative (CO3-) ion modes for detection of organic and inorganic compounds. We will show data of chamber and ambient measurements using H3O+, NH4+, NO+, and CO3- primary reagent ion modes and discuss the benefits and limitations of complementary ionization modes of the Bipolar FUSION PTR-TOF.

In this work, we present the development and comprehensive characterization of a novel chemical ionization source designed for real-time detection of trace gases and aerosol-related compounds. This source is compatible with proton-transfer-reaction (PTR) and other chemical ionization schemes, enabling the generation of both positive and negative analyte ions. Key innovations include fast reagent ion switching on the timescale of seconds, and the ability to operate across a broad range of ion-molecule reactor (IMR) pressures (1 - 10 mbar) and sample flow rates, enhancing flexibility for diverse measurement conditions.