Atmospheric ammonia (NH<sub>3</sub>) over the Paris megacity: 9 years of total column observations from ground-based infrared remote sensing

Abstract

Abstract. In this paper, we present the first multiyear time series of atmospheric ammonia (NH3) ground-based measurements in the Paris region (Créteil, 48.79∘ N, 2.44∘ E, France) retrieved with the midresolution “Observations of the Atmosphere by Solar absorption Infrared Spectroscopy” (OASIS) ground-based Fourier transform infrared solar observatory. Located in an urban region, OASIS has previously been used for monitoring air quality (tropospheric ozone and carbon monoxide) thanks to its specific column sensitivity across the whole troposphere down to the atmospheric boundary layer. A total of 4920 measurements of atmospheric total columns of ammonia have been obtained from 2009 to 2017, with uncertainties ranging from 20 % to 35 %, and have been compared with NH3 concentrations derived from the Infrared Atmospheric Sounding Interferometer (IASI). OASIS ground-based measurements show significant interannual and seasonal variabilities of atmospheric ammonia. NH3 total columns over the Paris megacity (12 million people) vary seasonally by 2 orders of magnitude from approximately 0.1×1016 molec. cm−2 in winter to 10×1016 molec. cm−2 for spring peaks, probably due to springtime spreading of fertilizers on surrounding croplands.

Multiscale observations of NH<sub>3</sub> around Toronto, Canada

“…showed a correlation of r = 0.79 and slope = 0.73. The same study also found that the FTIR in Paris is capable of providing information about NH 3 variability at a "regional" scale (∼ 120 km) Tournadre et al (2020). Although not quantified in this study, the line-of-sight through the atmosphere (which changes throughout the day) may also affect the representative scale of ground-based solar-pointing FTIR observations.…”

Emissions Reduction of Greenhouse Gases, Ozone Precursors, Aerosols and Acidifying Gases from Road Transportation during the COVID-19 Lockdown in Colombia

“…Consequently, containment measures implemented in various countries have shown changes in the air quality [11][12][13][14]. The use of fossil fuels by road vehicles is the main source of four groups of pollutants, including GHG [10], including carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O); ozone precursor gases, such as carbon monoxide (CO) [15], non-methane volatile organic compounds (NMVOC) [16], and nitrogen oxides (NOx) [17,18]; aerosols, including black carbon (BC) [10] and particulate matter (PM 2.5, PM 10 ) [15]; acidifying gases, such as ammonia (NH 3 ) [19] and sulfur dioxide (SO 2 ) [20]. GHG emissions, such as CO 2 , are mainly produced by power generation and road transport.…”

“…In addition, one of the main anthropogenic emissions sources of BC is the incomplete combustion of fossil fuels (especially diesel) in vehicles [10]. Acidifying gases are emitted by the combustion of biomass and fossil fuels as well as by industrial activity [19,20]. NH 3 emissions related to road traffic are due to use of catalytic NOx reduction systems on light and heavy-duty vehicles [19], whose devices use an injection of urea or ammonia [28].…”

“…Acidifying gases are emitted by the combustion of biomass and fossil fuels as well as by industrial activity [19,20]. NH 3 emissions related to road traffic are due to use of catalytic NOx reduction systems on light and heavy-duty vehicles [19], whose devices use an injection of urea or ammonia [28]. Recent studies showed that the containment measures to minimize the spread of SARS-CoV-2 have resulted in reductions of 15% to 40% in industrial sectors and temporarily reduced China's CO 2 emissions by 25%.…”

Multiscale observations of NH<sub>3</sub> around Toronto, Canada

“…A study by Hu et al (2014) investigating NH 3 in downtown Toronto has shown that greenery within the city, where chemical fertilizers are commonly used, is an important source of NH 3 when temperatures are above freezing and that potential sources at temperatures below freezing have yet to be investigated. Additionally, recent studies have shown the increased capacity for satellitebased instruments to measure spatial and temporal distributions of NH 3 total columns at global (Van Damme et al, 2014a;Warner et al, 2016;Shephard et al, 2020), regional (Van Damme et al, 2014b;Warner et al, 2017;Viatte et al, 2020), and point-source scales (Van Damme et al, 2018;Clarisse et al, 2019a;Dammers et al, 2019).…”