The ozone (O₃) sensor on the Go Direct^® Air Quality Sensor (GDX-AIRQ) does have cross-sensitivity to nitrogen dioxide (NO₂). Cross-sensitivity means that if you are measuring O₃ in an environment where NO₂ is also present, the O₃ readings will read artificially high.

To correct for this cross-sensitivity, make sure to have both the NO₂ and O₃ channels selected, then create a calculated column for the Corrected Ozone reading following the steps provided below. The correction will use the expression: “O₃” – 0.84 “NO₂”

In Graphical Analysis Pro to set up a calculated column:

1. Click or tap Column Options (three dot icon) next to the O₃ column header in the data table, then select Add Calculated Column.
2. Enter Corrected Ozone as the name and ppm as the units.
3. Click or tap Insert Expression and select Custom Expression.
4. Type O and select “O₃”, then type: − 0.84
5. Now type N and select “NO₂”
6. Click or tap Apply.