Instrument - RH, T, Ozone, NOx Combined Instrument (Seinfeld)
Short name:
RHTO3NOx
Full name:
RH, T, Ozone, NOx Combined Instrument (Seinfeld)
What is being measured:
Relative humidity (RH), Temperature (T), Ozone (O3), Nitrogen oxides (NO + NO2, NOx)
Sampling Protocol:
Online
Manufacturer:
Vaisala, Horiba, Teledyne
Model:
Vaisala HMM211, Horiba APOA-360, Teledyne 200
Instrument year
:
None specified
Data recording software:
Labview custom program
Data analysis software:
None
Raw data time resolution:
1 min
Analysis data averaging:
None
Detection limit:
1 ppb for Ozone, 0.5 ppb for NOx
Sensitivity to temperature (and correction method, if applicable):
:
None
Sensitivity to relative humidity (and correction method, if applicable):
:
NOx instrument is sensitive to RH, takes about an hour to re-equilibrate
Sampling method:
Direct sampling
Sample preparation method:
None
Sample residence time (chamber to instrument) (seconds):
Length of tubing (cm):
30
Instrument flow rate:
1 LPM
Tubing inner diameter:
Tubing material:
FEP Teflon
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:
None
Quantification method:
Instrument automatically applies calibration.
Calibration method:
Calibration of O3/NOx with standard gases. Calibration of RH with saturated salt solutions in the range of 11-90%.
Calibration drift estimate:
Calibration schedule:
Uncertainty estimation method:
Inquire with PI
Known interferences:
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:
Additional notes:
Measurement uncertainty:
Uncertainty in ozone is 10%, NOx is 20%, T/RH is 10%
Measurement units:
T (Celsius), RH (%), Ozone (ppb), NOx (ppb)