DISCLAIMER All NDACC data more than two years old are public data. Additionally some PIs have authorized their data for early release. Users are encouraged to consult the available NDACC documentation, references and to contact the NDACC French PIs for any question about the data sets or possible scientific collaboration. People who use NDACC data in a publication are requested to include the following acknowledgment: "The data used in this publication were obtained as part of the Network for the Detection of Atmospheric Composition Change (NDACC) and are publicly available”. A notification of publication should also be sent to the PIs.