Instrument - NO-NO2-NOx Chemiluminescence Analyzer
NO-NO2-NOx Chemiluminescence Analyzer
What is being measured:
Data recording software:
NI DAQ with Labview, recorded on MICAS-X
Data analysis software:
Raw data time resolution:
Analysis data averaging:
Sensitivity to temperature (and correction method, if applicable):
Sensitivity to relative humidity (and correction method, if applicable):
Direct sampling from chamber
Sample preparation method:
Sample residence time (chamber to instrument) (seconds):
Length of tubing (cm):
Instrument flow rate:
Tubing inner diameter:
Chemical identification method:
Chemiluminescence of NO2 at 405 nm after converting all NOx to NO and then reacting with excess O3 in one channel, and only measuring NO2 in another channel, then performing a subtraction of NOx - NO2 to get NO concentrations.
Data analysis method:
Concentration is as reported by the instrument.
Adding known amounts of NO or NO2 to the chamber from a dark bulb of known volume, where the chamber volume is calibrated by addition of CO2 and monitoring the change in concentration of CO2.
Calibration drift estimate:
Low (on the order of weeks)
Uncertainty estimation method:
Uncertainty is +/- 15%, estimated from standard deviations of replicate measurements, introduction of standard chemical into the chamber, including conversion of NO to NO2 from our NO standard cylinder.
Nitrites (i.e. methyl nitrite) used for OH generation by photolysis are read as NO2 on the NOx analyzer.
Link to supplemental information:
All units have uncertainties of 15% of absolute value.
All measurements from this instrument have units of ppmv.