Goals:
To make ppbv levels of HPALDs and associated compounds and observe their response in the suite of instrumentation. To photoxidize HPALDs and associated compounds and observe product species. Determination if HPALD (or associated cmpds) contributes toward interference on OH instrument.
Summary:
Overall, the experiment went well. Initial NO levels in the high NOx bag were ~500 pptv which we believe was a result of connecting the GTHOS instrument to the bag shortly before starting the experiment. The HPALD compounds were formed overnight by photolyzing CH3ONO in the presence of isoprene under low levels of UV light, at 40C. By 10AM HPALD levels were ~1.3 ppbv as observed by CF3O- CIMS, and isoprene had decayed by a factor of 2. After the initial rapid NO decrease to stationary level (~70 pptv), NO remained stable over the low light portion of the experiment. After instrumentation began sampling the reaction products, the low level UV lights were turned off, and then temperature was ramped down to 25C, and then back up to 40C over the period of an hour. Next, 20% of chamber UV lights were turned on for 45 miniutes, and then 100% UV lights were illuminated for approx. 1.5 hrs. When the high level of UV lights were turned on, the AMS detected particle nucleation, and NO3- CIMS observed increases in several ion signals.
Organization: 2014 FIXCIT Study
Lab Affiliation: California Institute of Technology
Chamber: Seinfeld chambers
Experiment Category: Gas phase chemical reaction
Oxidant: Hydroxyl radical
Reactants: ISOPRENE, Methyl nitrite
Reaction Type: Photooxidation
Relative Humidity: 5
Temperature: 40
Pressure: 750 Torr
Individual Files - View, select, and download individual files from this Dataset.
Zip File - Download a ZIP file containing all files.
Python script - Download all files via Python 3, preferred for all operating systems.
Wget shell script - Download all files using Wget, preferred for Linux.
Curl shell script - Download all files via Curl, preferred for MacOS.