Experiment: 2014 FIXCIT Study_20140109_ISOPRENE/Nitrogen dioxide/Ozone/Formaldehyde_Nitrate radical_N/A_Isoprene + NO3/HO2, dry, no seed


Name: 2014 FIXCIT Study_20140109_ISOPRENE/Nitrogen dioxide/Ozone/Formaldehyde_Nitrate radical_N/A_Isoprene + NO3/HO2, dry, no seed
Date: 2014-01-09

2014 FIXCIT Study

Seinfeld chambers

Experiment Set
FIXCIT experiments

Explore products formed due to isoprene + NO3 oxidation when under conditions that are more relevant to the atmosphere (i.e., NO3 and HO2 are both present in the chamber like ambient conditions). Turn on lights to confirm the formation of nitrooxyhydroxyepoxide from OH oxidation of nitrooxyhydroperoxide.

The experiment turned out well, and only a couple of instruments had an interference for formaldehyde. The NO CL monitor saw an interference and the LIF OHR saw diminished signal due to OH reacting with formaldehyde, but all other instruments ran smoothly. The LIF OHR was taken off of the experiment because the signal was too depleted to be useful. This helped save bag volume, so that the GTHOS could sample the entire experiment. Nitrooxyhydroperoxide, hydroxynitrate, and carbonylnitrate all formed in the dark and leveled off before turning on lights. When lights were turned on, nitrooxyhydroperoxide was oxidized via OH to nitrooxyhydroxyepoxide as expected.

Additional Notes
Instrument Status: TD LIF - up PTRMS - up GTHOS - up LIF OHR - up for beginning, signals were too low due to formaldehyde, so taken off CRM OHR - up NO CL - up GLY LIP - down FOR LIF - down I/A CIMS - up NCIMS - up RHTO3 - up GC FID - up AMS - up TQC1 - up, but had some overheating issues, so down part of the experiment. TQC2 - up TOFCIMS - up Bag Additions: O3, ~50 ppb Formaldehyde, ~4 ppm NO2, ~100 ppb (59 sec, 5L/min, from 488 ppm NO2 tank) Isoprene, ~18.2 ppb (verified with FT-IR and calculated based on 23m^3 bag volume at time of injection) Timeline (UTC, hrs): 15:00:00 - Cap bag, fill bag, and start O3/NOx monitors. 15:20:00 - Inject O3 (~50 ppb). 15:43:00 - Fill bag completely to confirm O3 concentration. 16:47:00 - Inject formaldehyde (~4 ppm). 17:17:00 - Start filling bag. 17:31:00 - Bag completely full. 17:32:00 - All instruments start sampling the bag. 18:04:00 - Inject NO2 (~100 ppb). 18:13:00 - Add pulses of injection air to facilitate mixing. 18:16:00 - Pulsing complete, cap the bag. 19:04:00 - Inject isoprene (~18 ppb). 19:16:00 - Inject pulses of injection air to facilitate mixing. 19:19:00 - Pulsing finished, cap bag for the last time. 19:32:00 - OH reactivity instrument taken offline. 22:04:00 - Turn on 100% lights. 24:04:00 - Turn off lights. 25:04:00 - All instruments stop sampling.

Experiment Details


  • Gas phase chemical reaction
Temperature: 26
Relative Humidity: 5
Seeded Experiment: No
Fuchs Adjusted Surface Area:
Condensation sink rate coefficient: 5
Reaction type:
Oxidant Name: Nitrate radical
Initial Oxidant Concentration Value: 3.8e8 (molecules_per_cubic_centimeter)
RO2 Main Fate: HO2
RO2 Lifetime: (Seconds)
Pressure: 750

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

Experiment Set Details

Name: FIXCIT experiments
Time format and units: Seconds past midnight
The Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT) was a collaborative study at the atmospheric chambers of Caltech during January 2014. FIXCIT is the laboratory component of SOAS, and is aimed toward (1) better understanding the chemical details behind ambient observations relevant to the southeastern United States, (2) advancing the knowledge of atmospheric oxidation mechanisms of important biogenic hydrocarbons, and (3) characterizing the behavior of field instrumentation using authentic standards. A series of chamber experiments was conducted to investigate the oxidation of isoprene, α-pinene, methacrolein, pinonaldehyde, acylperoxy nitrates, isoprene hydroxy nitrates (ISOPN), isoprene hydroxy hydroperoxides (ISOPOOH), and isoprene epoxydiols (IEPOX). Pinonaldehyde and isomer-specific standards of ISOPN, ISOPOOH, and IEPOX were synthesized, enabling study of the oxidation mechanisms and instrument responses for these compounds.


  • Allen H. Goldstein UC Berkeley
  • William H. Brune Penn State University
  • Ronald C. Cohen UC Berkeley
  • Delphine K. Farmer Colorado State University
  • Manjula R. Canagaratna Aerodyne
  • Douglas R. Worsnop Aerodyne
  • Jose L. Jimenez University of Colorado Boulder
  • Frank N. Keutsch Harvard
  • Saewung Kim UC Irvine
  • Alex B. Guenther UC Irvine
  • John E. Mak SUNY Stonybrook
  • Geoffrey S. Tyndall NCAR
  • Denise D. Montzka NCAR
  • Andrew J. Weinheimer NCAR
  • Alam Hasson Fresno State


Principal investigators:

Paul O. Wennberg
Phone: 626 395 2447
E-mail: wennberg@caltech.edu
OrcID: 0000-0002-6126-3854

John H. Seinfeld
Phone: 626-395-4635
E-mail: seinfeld@caltech.edu
OrcID: 0000-0003-1344-4068

John D. Crounse
Phone: 626-395-8655
E-mail: crounjd@caltech.edu
OrcID: 0000-0001-5443-729X

Tran B Nguyen
Phone: 5307525987
E-mail: tbn@ucdavis.edu
OrcID: 0000-0001-9206-4359

Data Manager:

Tran B. Nguyen
Phone: 5307525987
E-mail: tbn@ucdavis.edu


Reactant Compound type Concentration Concentration units
  • Alkene
18 Parts Per Billion
Nitrogen dioxide 100 Parts Per Billion
Ozone 50 Parts Per Billion
  • Aldehyde
4 Parts Per Million

20140109_expTimeline.csv Timeline

UTC_hr Action
15:00 Cap bag; fill bag and start O3/NOx monitors.
15:20 Inject O3 (~50 ppb).
15:43 Fill bag completely to confirm O3 concentration.
16:47 Inject formaldehyde (~4 ppm).
17:17 Start filling bag.
17:31 Bag completely full.
17:32 All instruments start sampling the bag.
18:04 Inject NO2 (~100 ppb).
18:13 Add pulses of injection air to facilitate mixing.
18:16 Pulsing complete; cap the bag.
19:04 Inject isoprene (~18 ppb).
19:16 Inject pulses of injection air to facilitate mixing.
19:19 Pulsing finished; cap bag for the last time.
19:32 OH reactivity instrument taken offline.
22:04 Turn on 100% lights.
24:04 Turn off lights.
25:04 All instruments stop sampling.

Light Flux Characterizations:
Particle Loss Characterizations:
Vapor Loss Characterizations:

Chamber Details

Name: Seinfeld chambers
Volume in cubic meters: 22
Shape: Rectangular Prism
Surface area in cubic meters: 48
Flow Mode: Batch
Flow through rate in liters per minute:
Body Material: Teflon
Body thickness: 2
Replacement date:
Replacement frequency: As needed
Cleaning method: Flushing with air Flushing with air with UV lights on Oxidation
o3 background: < 0.5 ppb
nox background: 40 ppt
Particle background in micrograms per cubic meter: < 0.01 ug/m3
Air filtration method: Custom filtration canisters to remove NOx, hydrocarbons, water, particles, ozone, SOx from pressurized ambient air.
Mixing method: 1
Mixing method material: Pulsed air jets, manually actuated
Temparature Control: Yes
Temparature measurements recorded: Yes
Temparature range (min degrees celcius): 10
Temparature range (max degrees celcius): 45
Humidity Control: Yes
Humidity Measurements Recorded: Yes
Relative humidity range (min percent): 4
Relative humidity range (max percent): 90
Particle experiment capability: 1
Lights: Yes
Light source type(s): UV black lamps (350 nm centered)
Supplemental information: https://www.worldscientific.com/doi/abs/10.1142/9789813147355_0001
Additional Notes: