Experiment: Caltech Atmospheric Chamber_20130908_trans-beta IEPOX_None_Ammonium sulfate_DarkReactiveUptake_RH69_addedNaOH


Name: Caltech Atmospheric Chamber_20130908_trans-beta IEPOX_None_Ammonium sulfate_DarkReactiveUptake_RH69_addedNaOH
Date: 2013-09-08

Caltech Atmospheric Chamber

Near/Far Bag 2012-2015 (Tran)

Experiment Set
IEPOX uptake experiments

This experiment was performed to assess the reactive uptake behavior of trans beta-IEPOX that was synthesized for the experiment. Different particle inorganic compositions (mainly ammonium sulfate or AS) and different particle water content were investigated. Particles are injected into the chamber as deliquesced droplets (through a wet wall denuder) and they stabilize to their equilibrium particle liquid water content depending on their hygroscopicity.

Large organic aerosol (OA) growth was observed on ammonium sulfate aerosol water where the pH was increased with NaOH. The atomizer solution was adjusted to neutral pH with NaOH, but the true pH of the particle is not known (however likely higher than without the NaOH addition).

Experiment Details


  • Condensed-phase chemical reaction
  • Multiphase chemical reaction
Temperature: 22
Relative Humidity: 69
Seeded Experiment: Yes
Type of Seed: Ammonium sulfate
Initial Seed Concentration Value: 70
Seed Concentration Units: micrograms_per_cubic_meter
Fuchs Adjusted Surface Area:
Condensation sink rate coefficient: 69
Reaction type:
Oxidant Name: None
Initial Oxidant Concentration Value: 0 (parts_per_billion)
RO2 Main Fate: Not applicable
RO2 Lifetime: (Seconds)
Pressure: 750 Torr

Data Set plots
Choose a file: Choose the X-Axis:

Experiment Set Details

Name: IEPOX uptake experiments
Time format and units: Experiment time (minutes, local)
Reactive uptake of cis and trans beta-IEPOX (isoprene epoxydiols with the epoxide in the 2-position, and the -CH2OH in the cis and trans conformations) onto dry and hydrated seeds of ammonium sulfate (AS), as well as other inorganic seeds. Note that wall loss is already applied to AMS particle data.


  • Tran B Nguyen UC Davis
  • Paul O Wennberg Caltech


Principal investigator:

John H Seinfeld
Phone: (626) 395-4635
E-mail: seinfeld@caltech.edu
OrcID: https://orcid.org/0000-0003-1344-4068

Data Manager:

Stephanie Kong
Phone: 626-395-3194
E-mail: wkong@caltech.edu


Reactant Compound type Concentration Concentration units
trans-beta IEPOX 160 Parts Per Billion

130908_Timeline.csv Timeline

Local time (hh:mm) Action
12:30 Inject ammonium sulfate ((NH4)2SO4) seeds with added NaOH until solution is at pH7 (0.06M atomizer soln) through wet wall denuder (chamber is at 70% RH)
12:50 Stop injecting seeds
13:23 (time 0) Inject IEPOX through heated bulb (68 Celsius)
16:00 CIMS fluorinated reagent ion ran out at this time so the signals of everything decreased in absolute terms (but the IEPOX has already stabilized)
16:50 Stopped IEPOX injection
19:30:00 Shutodown instruments

Light Flux Characterizations:
Particle Loss Characterizations:
Vapor Loss Characterizations:
2013-04-01 (#8)

Chamber Details

Name: Near/Far Bag 2012-2015 (Tran)
Volume in cubic meters: 27
Shape: Rectangular Prism
Surface area in cubic meters: 41.8
Flow Mode: Batch
Flow through rate in liters per minute:
Body Material: Teflon
Body thickness: 50
Replacement date:
Replacement frequency: As needed
Cleaning method: Flushing with air
o3 background: 0.5 ppb
nox background: 0.1 ppb for Near, > 0.1 ppb for Far
Particle background in micrograms per cubic meter: < 0.1 ug/m3
Air filtration method: Custom Filter
Mixing method: 0
Mixing method material:
Temparature Control: Yes
Temparature measurements recorded: Yes
Temparature range (min degrees celcius): 20
Temparature range (max degrees celcius): 45
Humidity Control: Yes
Humidity Measurements Recorded: Yes
Relative humidity range (min percent): 5
Relative humidity range (max percent): 100
Particle experiment capability: 1
Lights: Yes
Light source type(s): UVA Black Lamps
Supplemental information: https://www.worldscientific.com/doi/abs/10.1142/9789813147355_0001
Additional Notes: