Figure 2.

NO₂ comparisons from SAPHIR chamber experiments in Julich, Germany, in 2018 (experiments from 08 August, 14 August, 16 August, and 19 August). This figure shows illustrative scatter plots of the TD–CRDS NO₂ against the unified NO₂ data set from three independent Max Planck Institute run cavity ring-down measurements. These instruments have slightly varying relationships to one another day-to-day, suggesting the presence of inlet memory effects. Slopes were, for the most part, consistent within 10%, resulting in an estimated uncertainty of the AN measurements used here of 10%. Several days (August 9, 12, 16, and 21) had more scatter and thus poorly defined slopes with differences of up to 50%; these are indicated by italics in Table 1.