TROPOMI Nitrogen Dioxide (NO2)
Nitrogen Dioxide (NO2) plays a crucial role as a precursor to anthropogenic ozone and is a primary factor in generating various airborne compounds, such as nitric acid, fine particles, peroxyacetyl nitrate, nitrosamines, and nitro-polycyclic aromatic hydrocarbons. The TROPOMI instrument on Sentinel-5 Precursor retrieves tropospheric and stratospheric NO2 column products. It distinguishes stratospheric and tropospheric contributions, calculating air-mass factors for accurate conversion. TROPOMI NO2 data comes in various timeliness levels, including Near Real Time (NRTI), Offline (OFFL), and Reprocessed (RPRO) products. Each level corresponds to different processing baselines, ensuring users have access to timely information, long-term datasets, and improved accuracy through continuous updates and refinements. The OFFL and RPRO products, with distinct identifiers and DOIs, offer comprehensive information on tropospheric NO2 columns, precision estimates, and quality values, supporting diverse applications and research needs. Note that the data file contains tropospheric NO2 column, precision estimates, and a quality assurance value (qa_value) for interpreting data quality. Recommendations suggest using pixels with qa_value above 0.75 (or 0.5 for cloud-covered scenes).