Instrument - RH, T, Ozone, NOx Combined Instrument (Seinfeld)
RH, T, Ozone, NOx Combined Instrument (Seinfeld)
What is being measured:
Relative humidity (RH), Temperature (T), Ozone (O3), Nitrogen oxides (NO + NO2, NOx)
Vaisala, Horiba, Teledyne
Vaisala HMM211, Horiba APOA-360, Teledyne 200
Data recording software:
Labview custom program
Data analysis software:
Raw data time resolution:
Analysis data averaging:
1 ppb for Ozone, 0.5 ppb for NOx
Sensitivity to temperature (and correction method, if applicable):
Sensitivity to relative humidity (and correction method, if applicable):
NOx instrument is sensitive to RH, takes about an hour to re-equilibrate
Sample preparation method:
Sample residence time (chamber to instrument) (seconds):
Length of tubing (cm):
Instrument flow rate:
Tubing inner diameter:
Chemical identification method:
Ozone by UV absorption spectroscopy, NO by chemiluminescence upon reaction with ozone, NO2 by conversion to NO on a heated molybdenum catalyst. RH/T aren't chemicals.
Data analysis method:
Instrument automatically applies calibration.
Calibration of O3/NOx with standard gases. Calibration of RH with saturated salt solutions in the range of 11-90%.
Calibration drift estimate:
Uncertainty estimation method:
Inquire with PI
Ppm levels of H2O2 interferes with ozone measurement (small amount). NOy species (like PANs, org. nitrates, N2O5, etc.) interferes with NOx measurement as it's read as NO2.
Link to supplemental information:
Uncertainty in ozone is 10%, NOx is 20%, T/RH is 10%
T (Celsius), RH (%), Ozone (ppb), NOx (ppb)