Short name:
OHR-CRM

Full name:
OH Reactivity Comparative Rate Method (Kim/Guenther)

What is being measured:
Total OH reactivity

Sampling Protocol:
Online

Manufacturer:
Custom

Model:
Custom

Instrument year :
None specified

Data recording software:
Inquire with PI

Data analysis software:
Inquire with PI

Raw data time resolution:
Inquire with PI

Analysis data averaging:
Inquire with PI

Detection limit:
6 s-1

Sensitivity to temperature (and correction method, if applicable): :
Inquire with PI

Sensitivity to relative humidity (and correction method, if applicable): :
Inquire with PI

Sampling method:
Direct sampling

Sample preparation method:
None

Sample residence time (chamber to instrument) (seconds):

Length of tubing (cm):

Instrument flow rate:
0.5 SLM

Tubing inner diameter:

Tubing material:
PFA Teflon

Chemical identification method:
No chemicals are being identified

Data analysis method:
Inquire with PI

Quantification method:
In this method, a reactive molecule (X=pyrole), not normally present in air, is passed through a glass reactor and its concentration is monitored with a suitable detector. OH radicals are then introduced in the glass reactor at a constant rate to react with X, first in the presence of zero air and then in the presence of ambient air containing VOCs and other OH reactive species. Comparing the amount of X exiting the reactor with and without the ambient air allows the air reactivity to be determined.

Calibration method:
The system has been tested and calibrated with different single and mixed hydrocarbon standards showing excellent linearity and accountability with the reactivity of the standards.

Calibration drift estimate:

Calibration schedule:

Uncertainty estimation method:
Uncertainties include a 5% accuracy error inherent in the pyrrole gas standard and a 2σ precision error of 6%, while measuring pyrrole at 25 nmol mol−1

Known interferences:
high NO in ambient air, varying relative humidity and photolysis of pyrrole

Link to supplemental information:
https://core.ac.uk/download/pdf/52757217.pdf

Additional notes:

Measurement uncertainty:

Measurement units: