Update on Aerodyne development of PAM oxidation flow reactor

Andy Lambe, John Jayne, Wade Robinson, Xavier Cabral, Stephen PrescottAerodyne Research, Inc.

Bill BrunePennsylvania State University

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AERODYNE RESEARCH, Inc. 45 MANNING ROAD, BILLERICA, MA 01821 (978) 663 9500

www.aerodyne.com CACC_OPT_12_1

E. Kang, M. J. Root, D. W. Toohey, and W. H. Brune, Introducing the concept of Potential Aerosol Mass (PAM), Atmos.

Chem. Phys., 7, 5727–5744, 2007.

A. T. Lambe, A. T. Ahern, L. R. Williams, J. G. Slowik, J. P. S. Wong, J. P. D. Abbatt, W. H. Brune, N. L. Ng, J. P. Wright,

D. R. Croasdale, D. R. Worsnop, P. Davidovits, and T. B. Onasch, Characterization of aerosol photooxidation flow re-

actors: heterogeneous oxidation, secondary organic aerosol formation and cloud condensation nuclei activity measure-

ments, Atmos. Meas. Tech., 4, 445–461, 2011.

D. S. Tkacik, A. T. Lambe, S. Jathar, X. Li, A. A. Presto, Y. Zhao, D. R. Blake, S. Meinardi, J. T. Jayne, P. L. Croteau,

and A. L. Robinson, Secondary organic aerosol formation from in-use motor vehicle emissions using a Potential Aerosol

Mass reactor. Environ. Sci. Technol., 48, 11235-11242, 2014.

R. Li, B.B. Palm, A.M. Ortega, J. Hlywiak, W. Hu, Z. Peng, D.A. Day, C. Knote, W.H. Brune, J. de Gouw, and J. L. Jime-

nez. Modeling the radical chemistry in an Oxidation Flow Reactor: radical formation and recycling, sensitivities, and OH

exposure estimation equation. J. Phys. Chem. A, 2015.

PAM Wiki: https://sites.google.com/site/pamwiki/

Figure demonstrating PAM capabilities

Oxidant production in the PAM reactor

PAM overview

O2 + hv185 2O(3P)

O(3P) + O2 O3

O3 + hn254 O(1D) + O2

O(1D) + H2O 2OH

H2O + hn185 OH + HH + O2 HO2

• Field-deployable oxidation flow reactor developed by Bill Brune[Kang et al., ACP, 2007] and further evaluated by Lambe et al. (2011)

• Production of secondary aerosol, oxidized primary aerosol

• https://sites.google.com/site/pamwiki/publications [search ‘PAMwiki’]

https://sites.google.com/site/pamwiki/publications

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3days

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Photochemical age

NH4OrgSO4NO3

16:00 16:30 17:00 17:30 18:0015:30

Local Time

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• PAM OH concentrations range from 2.0 × 108 to 2.2 ×1010 molec cm−3 with exposure times of 100 s.

• Environmental chamber OH concentrations range from 2 × 106 to 2 × 107 molec cm−3

with exposure times of several hours.

ARI PAM Reactor Package

• Mounted in an enclosure.• More efficient fluorescent

lamps with electronic diming.

• Two interchangeable lamp options (λ= 185, 254 nm) to decouple O3 production in the cell.

• Separate O3 production cell.

• Control electronics and software for running event sequences.

ARI PAM Oxidation Flow Reactor

• Penn State PAM reactor design & new UV lamps with dimmable ballasts

• Ozone generator with lamp/dimmable ballast

• UV photodetector, RH/T sensors, Nafion humidifier, Aerodyne autovalve

• Control software with data-logging, automated control with event sequencing

• Penn State photochemistry model for predicting HOx radical concentrations atspecified operating conditions

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• PAM units supplied with two interchangeable O3-free lamps (l = 254 nm) todecouple O3 and OH production if needed

• Lamps mounted inside GE214 quartz sleeves and flushed with N2 gas

O3 formation potential (l = 185, 254 nm)

Ultraviolet C photodetector

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• Mounted in back end plate for in situ UV measurement• Connect to OH exposure (calibrated with SO2, CO, etc.) and Penn State

photochemical model • UV lamp diagnostic

• Test data: Measured irradiance of two UV lamps (l = 254 nm)

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High Output (HO) Quartz LampsHigh Output (HO) lamps yield up to 66% more UV output when compared to

standard lamps of the same length. HO lamps offer system designers unique

opportunities to decrease the number of lamps required without compromising

functionality of the system. This has the added potential benefits of reduced

system footprint, increased efficiency and/or increased system capacity.

HO lamps are produced and are available in the same configurations of standard

lamps. Custom lengths and configurations may also be produced to the customer's specific requirements.

The table below represents a sampling of the more common lamp sizes. We can custom design the ideal HO lamp

for your unique application.

High Output (HO) Quartz Germicidal Lamps

Preheat&

Instant StartConfigurations

Available!

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Tube Arc UV output1 Rated1

Diameter BF - BF Length Power1 Current Voltage1 @ 254nm Life

mm mm mm W mA V µW/cm² W hrs.

Low Ozone

GHO436T5L 15 436 360 48 800 60 120 13 16,000

GHO36T5L 15 842 755 87 800 110 260 28 16,000

GHO846T5L 15 846 767 90 800 113 265 29 16,000

GHO893T5L 15 893 815 95 800 120 270 30 16,000

GHO64T5L 15 1554 1421 155 800 195 395 54 16,000

Ozone Generating

GHO436T5VH 15 436 360 48 800 60 120 13 16,000

GHO36T5VH 15 842 755 87 800 110 260 28 16,000

GHO846T5VH 15 846 767 90 800 113 265 29 16,000

GHO893T5VH 15 893 815 95 800 120 270 30 16,000

GHO64T5VH 15 1554 1421 155 800 195 395 54 16,000

Note 1: Lamp data is based on measurements performed under laboratory conditions in air at room ambient temperature. Measurements were performed on a high-frequency, current limited electronic ballast and represent average values at 1 meter.

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software

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