Dekati® Oxidation Flow Reactor DOFR™


Dekati® Oxidation Flow Reactor, DOFR™, is a constant flow oxidation flow reactor for secondary aerosol (SA) formation studies. The formation of secondary aerosols can take several days in the atmosphere and the purpose of the oxidation flow reactor is to speed up these processes. In the Dekati® DOFR™, the formation processes are accelerated by creating highly oxidative conditions for the aerosol sample and the timescale is reduced from days to less than one minute. The flow through the oxidation chamber is kept constant and laminar, resulting in minimal particle losses. All these features make the DOFR an ideal tool for PAM (Potential Aerosol Mass) measurements and SA formation research.

In the DOFR™, the aerosol sample passes through a laminar flow reactor where it is exposed to high intensity UV radiation. The UVC radiation together with water molecules and ozone in the sample create highly oxidative conditions inside the reactor speeding up the formation of secondary aerosols. The size, concentration and mass of the aerosol is then monitored with a particle measurement instrument connected at the outlet of the reactor. For example, the Dekati® ELPI®+ (Electrical Low Pressure Impactor) is well suited for monitoring the particle size  distribution and concentration in real time after the reactor. The key advantage of the Dekati® DOFR™ is its very low aerosol sample residence time. This short residence time together with the laminar flow profile inside the reactor make the DOFR™ an ideal tool to study even transient emission sources such as engine tailpipe emissions in variable driving conditions.


  • Fast oxidation flow reactor for secondary aerosol formation studies
  • Design based on the TSAR reactor developed by Tampere University
  • Constant reactor flow with short sample residence time
  • Up to 1 month photochemical age for aerosol
  • Laminar sample flow with negligible fine particle losses
  • High output sample flow for measurement instruments
  • Adjustable UV intensity with 12 UVC lamps operating at 254 nm
  • Integrated UV sensor for light intensity measurement included
  • Integrated cooling for UV lamps included
  • Integrated ejector diluter for diluting the sample for measurement instruments and flow control included
  • Compact, portable design
  • Separate sample conditioning unit with primary dilution, humidity adjustment, ozone generation and RH and O3 sensors available soon. Sample conditioning unit is fully compatible with the DOFR™ system.

* Humidifier and O3 generator not included in the DOFR™, they will be included in a separate sample conditioning unit that is available soon.


Applications for the Oxidation Flow Reactor OFR

  • Secondary aerosol formation research
  • PAM (Potential Aerosol Mass) measurements
  • Transient emission source measurements
  • Engine tailpipe emission research
  • Marine engine studies
  • Aircraft emission research
  • Stationary source emissions studies

What is potential aerosol mass PAM?

Term secondary aerosol is used to refer to the particulate mass that is formed through chemical reactions in the atmosphere, long after the actual emission from the source into the air. Secondary aerosol is formed when volatile compounds originated from the source react in the atmosphere with highly reactive oxidative species and form new compounds. The volatile compounds that have potential to form new compounds are called precursors, and they can be either organic or inorganic molecules. When the precursor compounds and the oxidative species react, they form new compounds that can have lower volatility than the original precursor molecules emitted from the source. These newly formed low volatility compounds can then form new particles via nucleation or grow existing particles via condensation. This process is called aging of the aerosol and the potentially formed aerosol mass is commonly referred to as PAM (Potential Aerosol Mass). DOFR™ is designed to determine the maximum PAM for the source aerosol in a matter of minutes by adjusting different oxidation parameters.