Pakokaasujen

Pakokaasujen (Finnish for "exhaust gases") are the gaseous and particulate emissions produced by combustion processes, most commonly from internal combustion engines, power plants, industrial furnaces and incinerators. They form when fuel reacts with oxygen, releasing energy and a mixture of combustion products that are expelled to the atmosphere.

Typical components include carbon dioxide (CO2) and water vapor — the primary products of complete combustion — along with pollutants generated by incomplete combustion or fuel impurities: carbon monoxide (CO), oxides of nitrogen (NOx), sulfur dioxide (SO2), volatile organic compounds (VOCs), particulate matter (PM), and trace metals. The exact composition varies with fuel type, combustion conditions and emission-control technologies.

Pakokaasujen contribute to climate change, air quality degradation and human health risks. CO2 is a major greenhouse gas; NOx and VOCs participate in ground-level ozone formation; SO2 and NOx can cause acid deposition; fine particulates are linked to respiratory and cardiovascular disease. Local impacts include smog, reduced visibility and odor nuisance.

Regulation and control combine source controls, after-treatment and fuel quality measures. Common technologies include catalytic converters, diesel particulate filters, selective catalytic reduction for NOx, and flue-gas desulfurization in power plants. Vehicle emission standards (e.g., Euro standards) and air quality legislation set limits and monitoring requirements. Long-term mitigation emphasizes cleaner fuels, electrification of transport, energy efficiency and process changes to reduce reliance on combustion.