Abstract: The invention relates to a method for in-situ measurement of the concentration of gaseous chemical species contained in a biogas (10) flowing in a pipe (20), for example in a biogas treatment plant or a system using biogas. The method according to the invention is implemented by means of an optical measurement system (40) including a light source (41) and a spectrometer (44). Source (41) emits a UV radiation (42) through the biogas (10) within a measurement zone (21) in the pipe. Spectrometer (44) detects at least part of said UV radiation that has passed through biogas (10) and it generates a digital signal of the light intensity (50) as a function of the wavelength of the part of the UV radiation that has passed through the biogas. The chemical species concentration is then determined from digital light intensity signal (50).

Abstract: The present invention relates to an installation for depollution of the exhaust gas circulating in an exhaust line (10), notably from an internal-combustion engine, comprising at least one catalysis means for selective catalytic reduction of nitrogen oxides (NOx), at least one particle elimination means, a main tank (26) comprising at least one particle reducing agent and means (20) for feeding the reducing agent into the exhaust line. According to the invention, the installation comprises reducing agent additivation means (30).

Abstract: The present invention relates to an installation for depollution of the exhaust gas circulating in an exhaust line (10), notably from an internal-combustion engine, comprising at least one catalysis means for selective catalytic reduction of nitrogen oxides (NOx), at least one particle elimination means, a main tank (26) comprising at least one particle reducing agent and means (20) for feeding the reducing agent into the exhaust line. According to the invention, the installation comprises reducing agent additivation means (30).