Experiment: Nguyen Group_20210225_ALPHA-PINENE/Dinitrogen pentoxide_Nitrate radical_Ammonium sulfate
Experiment
Name: Nguyen Group_20210225_ALPHA-PINENE/Dinitrogen pentoxide_Nitrate radical_Ammonium sulfate
Date: 2021-02-25
Organization
Nguyen Group
Chamber
Tran's big bag of air
Experiment Set
a-pinene nighttime chemistry
Goals
To quantify the nitrooxy-hydroperoxide yield and the SOA yield from nighttime RO2+RO2-dominated NO3-initiated chemistry of a-pinene using N2O5. This experiment was predominantly to collect a filter to analyze the chemical content of pinene+NO3 RO2+RO2 SOA by offline HRMS.
Summary
a-pinene and seed aerosol were injected into the chamber, followed by N2O5, which quickly dissociated to NO2 and NO3. a-pinene decayed rapidly by reaction with NO3. Gas phase was monitored by CF3O- CIMS and particle formation by SMPS. After all injections, a filter was collected for offline HRMS analysis.Experiment Details
Categories:
- Gas phase chemical reaction
- Aerosol formation
Relative Humidity: 5
Seeded Experiment: Yes
Type of Seed: Ammonium sulfate
Initial Seed Concentration Value: 350
Seed Concentration Units: micrograms_per_cubic_meter
Fuchs Adjusted Surface Area:
Condensation sink rate coefficient: 5
Reaction type:
Oxidant Name: Nitrate radical
Initial Oxidant Concentration Value: 0 (parts_per_trillion)
RO2 Main Fate: RO2
RO2 Lifetime: (Seconds)
Pressure: 755 Torr
Data Set plots
Experiment Set Details
Name: a-pinene nighttime chemistry
Time format and units: HH:MM, local time
Description:
A series of experiments examining product yields and SOA formation from a-pinene + NO3 under conditions spanning a range of RO2 fates and under conditions designed to mimic the nighttime chemistry of the Southeast US in the summer. Two types of experiments are included: those in which the chemistry is initiated by addition of N2O5, which provides an easy NO3 source but tends to deviate from ambient conditions (i.e., no HO2 or ozone, and usually extremely high NO3 and/or RO2), and those in which the chemistry is initiated with O3 + NO2 + H2O2, which together provide conditions more closely resembling the ambient atmosphere at night (i.e., with HO2 and ozone in addition to NO3 and pinene) but have much more complex chemistry to untangle (simultaneous a-pinene + NO3, a-pinene + O3, and a-pinene + OH oxidation). For each experiment initiated with O3 + NO2 + H2O2, an additional control experiment without NO2 was run to account for this complex "background" (non-NO3) chemistry.
Collaborators:
- Kelvin H Bates Harvard / UC Davis
Contacts
Principal investigator:
Tran B. Nguyen
Phone: 5307525987
E-mail: tbn@ucdavis.edu
OrcID: 0000-0001-9206-4359
Data Manager:
Kelvin H. Bates
E-mail: kelvinhbates@gmail.com
210225_timeline.csv
Timeline
| Tine_HH:MM | Action |
| 9:00 | Instruments on |
| 9:18 | Start atomizing (25 min) and injecting a-pinene (35.5 min) |
| 9:54 | All injections stop |
| 11:12 | Inject N2O5 with pulsed mixing air |
| 11:15 | Start filter collection |
| 15:58 | Stop filter |
Citations
Characterizations
(None)
Particle Loss Characterizations:
(None)
Vapor Loss Characterizations:
(None)
Chamber Details
Name: Tran's big bag of air
Volume in cubic meters: 10
Shape: Rectangular Prism
Surface area in cubic meters: 28
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:
Particle background in micrograms per cubic meter:
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):
Temparature range (max degrees celcius):
Humidity Control: Yes
Humidity Measurements Recorded: Yes
Relative humidity range (min percent):
Relative humidity range (max percent):
Particle experiment capability: 1
Lights: Yes
Light source type(s):
UV broadband black lights (centered at 350 nm)
Supplemental information:
Additional Notes: 40-Watt, Osram/Sylvania 350nm black lights, 48” long, T12 fluorescent; 72 bulbs, 36 each on two facing walls, with UV-reflective siding on all walls. Lights are controlled via 6 panels (3 on the right wall - top, mid, bottom - and 3 equivalent on the left wall).