A new oxidation flow reactor for measuring secondary aerosol formation of rapidly changing emission sources

Pauli Simonen, Erkka Saukko, Panu Karjalainen, Hilkka Timonen, Matthew Bloss, Päivi Aakko-Saksa, Topi Rönkkö, Jorma Keskinen, Miikka Dal Maso

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    Abstract

    Oxidation flow reactors (OFRs) or environmental chambers can be used to estimate secondary aerosol formation potential of different emission sources. Emissions from anthropogenic sources, such as vehicles, often vary on short timescales. For example, to identify the vehicle driving conditions that lead to high potential secondary aerosol emissions, rapid oxidation of exhaust is needed. However, the residence times in environmental chambers and in most oxidation flow reactors are too long to study these transient effects (∼ 100 s in flow reactors and several hours in environmental chambers). Here, we present a new oxidation flow reactor, TSAR (TUT Secondary Aerosol Reactor), which has a short residence time (∼ 40 s) and near-laminar flow conditions. These improvements are achieved by reducing the reactor radius and volume. This allows studying, for example, the effect of vehicle driving conditions on the secondary aerosol formation potential of the exhaust. We show that the flow pattern in TSAR is nearly laminar and particle losses are negligible. The secondary organic aerosol (SOA) produced in TSAR has a similar mass spectrum to the SOA produced in the state-of-the-art reactor, PAM (potential aerosol mass). Both reactors produce the same amount of mass, but TSAR has a higher time resolution. We also show that TSAR is capable of measuring the secondary aerosol formation potential of a vehicle during a transient driving cycle and that the fast response of TSAR reveals how different driving conditions affect the amount of formed secondary aerosol. Thus, TSAR can be used to study rapidly changing emission sources, especially the vehicular emissions during transient driving.

    Original languageEnglish
    Pages (from-to)1519-1537
    Number of pages19
    JournalAtmospheric Measurement Techniques
    Volume10
    Issue number4
    DOIs
    Publication statusPublished - 2017
    MoE publication typeA1 Journal article-refereed

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  • Cite this

    Simonen, P., Saukko, E., Karjalainen, P., Timonen, H., Bloss, M., Aakko-Saksa, P., Rönkkö, T., Keskinen, J., & Dal Maso, M. (2017). A new oxidation flow reactor for measuring secondary aerosol formation of rapidly changing emission sources. Atmospheric Measurement Techniques, 10(4), 1519-1537. https://doi.org/10.5194/amt-10-1519-2017