A novel high-volume Photochemical Emission Aging flow tube Reactor (PEAR)

Ihalainen, Mika; Tiitta, Petri; Czech, Hendryk; Yli‐Pirilä, Pasi; Hartikainen, Anni; Kortelainen, Miika; Tissari, Jarkko; Scheibe, Benjamin; Sklorz, Martin; Suhonen, Heikki; Lamberg, Heikki; Leskinen, Ari; Kiendler‐Scharr, Astrid; Harndorf, Horst; Zimmermann, Ralf; Jokiniemi, Jorma; Sippula, Olli

doi:10.1080/02786826.2018.1559918

Cited by 32 publications

(37 citation statements)

References 78 publications

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“…One of the experimental challenges is to achieve extended aging time periods because the average atmospheric lifetime of soot particles is approximately 1 week (Textor et al, 2006). A common approach is the application of (photo-)oxidation flow reactors (OFRs) like the Potential Aerosol Mass (PAM) chamber (Kang et al, 2007), the Toronto Photo-Oxidation Tube (TPOT; George et al, 2007), the Micro Smog Chamber (MSC; Keller and Burtscher, 2012), the TUT Secondary Aerosol Reactor (TSAR; Simonen et al, 2017) or the Photochemical Emission Aging flow tube Reactor (PEAR; Ihalainen et al, 2019). Within these devices, the residence time ranges from 3 to 170 s and the OH-radical concentration ranges from 4.9 × 10 8 to 130 × 10 8 molec cm −3 , while the average atmospheric OH-radical concentration is orders of magnitude lower with 1.5 × 10 6 molec cm −3 (Mao et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Impact of isolated atmospheric aging processes on the cloud condensation nuclei activation of soot particles

et al. 2019

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Abstract. The largest contributors to the uncertainty in assessing the anthropogenic contribution in radiative forcing are the direct and indirect effects of aerosol particles on the Earth's radiative budget. Soot particles are of special interest since their properties can change significantly due to aging processes once they are emitted into the atmosphere. Probably the largest obstacle for the investigation of these processes in the laboratory is the long atmospheric lifetime of 1 week, requiring tailored experiments that cover this time span. This work presents results on the ability of two types of soot, obtained using a miniCAST soot generator, to act as cloud condensation nuclei (CCN) after exposure to atmospherically relevant levels of ozone (O3) and humidity. Aging times of up to 12 h were achieved by successful application of the continuous-flow stirred tank reactor (CSTR) concept while allowing for size selection of particles prior to the aging step. Particles of 100 nm diameter and rich in organic carbon (OC) that were initially CCN inactive showed significant CCN activity at supersaturations (SS) down to 0.3 % after 10 h of exposure to 200 ppb of O3. While this process was not affected by different levels of relative humidity in the range of 5 %–75 %, a high sensitivity towards the ambient/reaction temperature was observed. Soot particles with a lower OC content required an approximately 4-fold longer aging duration to show CCN activity at the same SS. Prior to the slow change in the CCN activity, a rapid increase in the particle diameter was detected which occurred within several minutes. This study highlights the applicability of the CSTR approach for the simulation of atmospheric aging processes, as aging durations beyond 12 h can be achieved in comparably small aerosol chamber volumes (<3 m3). Implementation of our measurement results in a global aerosol-climate model, ECHAM6.3-HAM2.3, showed a statistically significant increase in the regional and global CCN burden and cloud droplet number concentration.

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Section: Introductionmentioning

confidence: 99%

Impact of isolated atmospheric aging processes on the cloud condensation nuclei activation of soot particles

et al. 2019

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“…One of the experimental challenges is achieving extended ageing time periods since the average atmospheric lifetime of soot particles is approximately one week (Textor et al, 2006). A common approach is the application of (photo-)Oxidation Flow Reactors (OFR) like the Potential Aerosol Mass (PAM) chamber (Kang et al, 2007), Toronto Photo-Oxidation Tube (TPOT; George et al, 2007), Micro Smog Chamber (MSC;Keller and Burtscher, 2012), the TUT Secondary Aerosol Reactor (TSAR; Simonen et al, 2017) or the Photochemical Emission Aging flow tube Reactor 35 (PEAR; Ihalainen et al, 2019). Within these devices, the residence time ranges from 3 to 170 s and the OH-radical concentration ranges from 4.9 × 10 8 to 130 × 10 8 molec•cm -3 , while the average atmospheric OH-radical concentration is orders of magnitude less with 1.5 × 10 6 molec•cm -3 (Mao et al, 2009).…”

mentioning

confidence: 99%

Impact of Isolated Atmospheric Aging processes on the Cloud Condensation Nuclei-activation of Soot Particles

Friebel¹,

Lobo²,

Neubauer³

et al. 2019

Preprint

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Abstract. The largest contributors to the uncertainty in assessing the anthropogenic contribution in radiative forcing are the direct and indirect effects of aerosol particles on the Earth's radiative budget. Soot particles are of special interest since their properties can change significantly due to aging processes once they are emitted to the atmosphere. Probably the largest obstacle for the investigation of these processes in the laboratory is the long atmospheric lifetime of one week, demanding tailored experiments that cover this time span. This work presents results on the ability of two types of soot to act as cloud condensation nuclei (CCN) after exposure to atmospherically relevant levels of ozone and humidity. Aging times of up to 12&#8201;h were achieved by successful application of the continuous-flow stirred tank reactor (CSTR) concept while allowing for size-selection of particles prior to the aging step. 100&#8201;nm particles rich in organic carbon (OC) that were initially CCN-inactive showed significant CCN-activity at supersaturations (SS) down to 0.3&#8201;% after 10&#8201;h of exposure to 200&#8201;ppb of ozone. While this process was not affected by different levels of relative humidity in the range 5&#8211;75&#8201;%, a high sensitivity towards the ambient/reaction temperature was observed. Soot particles with a lower OC-content demanded an approximately four-fold longer aging duration to show CCN-activity for the same SS. Prior to the slow change in the CCN-activity, a rapid increase in the particle diameter was detected which occurred within several minutes. This study highlights the applicability of the CSTR-approach for the simulation of atmospheric aging processes, as aging durations beyond 12&#8201;h can be achieved in comparably small aerosol chamber volumes (<&#8201;3&#8201;m3). Implementation of our measurement results on the CCN-activity of soot particles retrieved from measurements at atmospherically relevant conditions into a global aerosol-climate model showed a statistically significant increase in the regional and global CCN burden and cloud droplet number concentration (CDNC).

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“…Further, we test the t act concept on real experimental data and finally apply it to other types of continuous-flow aging chambers such as OFRs. We show that application of the t act concept is capable of giving new insights into OFR data and further significantly improves the understanding of discrepancies in experimental results obtained in intercomparison studies (Lambe et al, 2011) with different reactors, such as the potential aerosol mass chamber (PAM; Kang et al, 2007) and the Toronto Photo-Oxidation Tube (TPOT; George et al, 2007).…”

Section: Motivationmentioning

confidence: 85%

“…The ideal OFR would be an ideal plug flow reactor (PFR) with the RTD being a Dirac delta function, often referred to as an impulse function. However, all OFRs have an RTD that lies between an ideal CSTR and an ideal PFR and is further dependent on the individual design of the OFR (George et al, 2007;Huang et al, 2017;Ihalainen et al, 2019;Kang et al, 2007;Simonen et al, 2017). Lambe et al (2011) already suggested that the RTD reduces the comparability of results from different OFR types.…”

Section: Application Of T Act To Other Continuous-flow Aerosol Chambersmentioning

confidence: 99%

answer to reviewer 2_corr

Friebel¹

2019

Preprint

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A novel high-volume Photochemical Emission Aging flow tube Reactor (PEAR)

Cited by 32 publications

References 78 publications

Impact of isolated atmospheric aging processes on the cloud condensation nuclei activation of soot particles

Impact of isolated atmospheric aging processes on the cloud condensation nuclei activation of soot particles

Impact of Isolated Atmospheric Aging processes on the Cloud Condensation Nuclei-activation of Soot Particles

answer to reviewer 2_corr

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