Abgases

Abgases, or exhaust gases, are gaseous waste products released by the combustion of fuels in engines and industrial equipment. They are expelled through exhaust systems and may originate from cars, trucks, ships, power plants, and boilers. The composition and volume of abgases depend on the fuel type, engine design, operating conditions, and the presence of emission-control systems.

Common constituents include nitrogen (N2) and oxygen (O2) from the intake air, carbon dioxide (CO2) from carbon oxidation, carbon monoxide (CO) from incomplete combustion, nitrogen oxides (NOx), sulfur oxides (SOx) when sulfur-containing fuels are burned, water vapor, particulate matter such as soot, and a range of volatile organic compounds. The share of each component varies; advanced engines and after-treatment technologies aim to reduce the most harmful constituents, especially CO, NOx, and particulates.

Environmental and health impacts: Abgases contribute to air pollution, climate change, and adverse health effects. CO and NOx can irritate the respiratory system; NOx and SOx contribute to acid rain; particulate matter affects lung function; CO2 is a greenhouse gas contributing to global warming. Regulations seek to limit emission levels and set testing standards.

Regulation and measurement: Emissions are regulated by national and international standards, such as vehicle emission standards and industrial emission limits. Emissions are quantified by mass per distance (for vehicles) or mass per energy output, measured by laboratory tests or portable monitoring. Policy also encourages fuel quality improvements and electrification to reduce exhaust generation.

Mitigation technologies: After-treatment devices include catalytic converters that oxidize CO and hydrocarbons and reduce NOx, diesel oxidation catalysts, diesel particulate filters, and selective catalytic reduction (SCR) to convert NOx into nitrogen and water using ammonia or urea. Engine-integrated strategies include exhaust gas recirculation (EGR), improved combustion efficiency, and alternative fuels.