Abstract
Abstract. A new simulation chamber has been built at the Interuniversitary Laboratory of Atmospheric Systems (LISA). The CESAM chamber (French acronym for Experimental Multiphasic Atmospheric Simulation Chamber) is designed to allow research in multiphase atmospheric (photo-) chemistry which involves both gas phase and condensed phase processes including aerosol and cloud chemistry. CESAM has the potential to carry out variable temperature and pressure experiments under a very realistic artificial solar irradiation. It consists of a 4.2 m3 stainless steel vessel equipped with three high pressure xenon arc lamps which provides a controlled and steady environment. Initial characterization results, all carried out at 290–297 K under dry conditions, concerning lighting homogeneity, mixing efficiency, ozone lifetime, radical sources, NOy wall reactivity, particle loss rates, background PM, aerosol formation and cloud generation are given. Photolysis frequencies of NO2 and O3 related to chamber radiation system were found equal to (4.2 × 10−3 s−1) for JNO2 and (1.4 × 10−5 s−1) for JO1D which is comparable to the solar radiation in the boundary layer. An auxiliary mechanism describing NOy wall reactions has been developed. Its inclusion in the Master Chemical Mechanism allowed us to adequately model the results of experiments on the photo-oxidation of propene-NOx-Air mixtures. Aerosol yields for the α-pinene + O3 system chosen as a reference were determined and found in good agreement with previous studies. Particle lifetime in the chamber ranges from 10 h to 4 days depending on particle size distribution which indicates that the chamber can provide high quality data on aerosol aging processes and their effects. Being evacuable, it is possible to generate in this new chamber clouds by fast expansion or saturation with or without the presence of pre-existing particles, which will provide a multiphase environment for aerosol-droplet interaction.
Highlights
It is well known that the emission of pollutants such as nitrogen oxides, volatile organic compounds (VOC), and particulate matter into the troposphere may present a health risk either directly, or as a result of their transformation
For indoor Teflon® film chambers, temperature control is sometimes achieved by using air conditioning of the room (Takekawa et al, 2003; Carter et al, 2005; Paulsen et al, 2005) while for rigid chambers, a cooling liquid is allowed to circulate around the reactor (Akimoto et al, 1979a; Barnes et al, 1979; De Haan et al, 1999; Glowacki et al, 2007; Saathoff et al, 2009)
In order to determine the photolysis frequency of the key species involved in this system and to better rationalize the heterogeneous wall reactions deduced from the timeconcentration curves, a kinetic numeric model of the NOx photo-oxidation system was built by using the chemical reactions and the kinetic parameters gathered and evaluated by Atkinson et al (2004, 2006, 2007). 36 chemical reactions including 7 photochemical reactions were introduced in the model
Summary
It is well known that the emission of pollutants such as nitrogen oxides, volatile organic compounds (VOC), and particulate matter into the troposphere may present a health risk either directly, or as a result of their transformation. For indoor Teflon® film chambers, temperature control is sometimes achieved by using air conditioning of the room (Takekawa et al, 2003; Carter et al, 2005; Paulsen et al, 2005) while for rigid chambers, a cooling liquid is allowed to circulate around the reactor (Akimoto et al, 1979a; Barnes et al, 1979; De Haan et al, 1999; Glowacki et al, 2007; Saathoff et al, 2009) In this latter design, the temperature range available is often larger allowing these chambers to be baked in order to facilitate low vapor pressure compounds desorption during cleaning (Akimoto et al, 1979a; De Haan et al, 1999) or to study low temperature processes (Field et al, 2006; Saathoff et al, 2009; Behnke et al, 1988). Aside the study of the physico-chemical behavior of atmospheric pollutants, CESAM can be used as a test platform for field instrument development or calibration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
