First multi-year ground-based measurements of NH 3 total columns over the Paris region (France), from the OASIS FTIR solar observatory

Ammonia (NH 3 ) is a reactive air pollutant strongly affecting both environment and human health. Massive industrial production of ammonia and the development of crops enhancing biological nitrogen fixation disturb the natural cycle and contribute to eutrophication, loss of biodiversity and acidification of various environments (soils, lakes, streams, etc.) (Galloway et al., 2003). Within the troposphere, NH 3 can react with SO 2 or HNO 3 to produce fine particulate matter (PM2.5) of ammonium salts (Behera et al., 2013). Thus, measuring atmospheric ammonia is necessary to better constraint particulate matter formation and reactive nitrogen budgets in air quality models. In the present study, we use the mid-resolution OASIS (Observations of the Atmosphere by Solar absorption Infrared Spectroscopy) ground-based FTIR solar observatory (Viatte et al., 2011 ; Chelin et al., 2015) to derive ammonia total columns over Paris suburbs (Creteil, 48.79°N, 2.44°E, France) using the PROFFIT inversion code (Hase et al., 2004). Thus, we have obtained the first multi-year time series of NH 3 ground-based measurements in Paris region (2009-2016). We analyze diurnal and seasonal variabilities of NH3 and study the relationship with meteorological variables. We also compare NH 3 total columns derived from OASIS and those from IASI satellite measurements (Whitburn et al., 2016).