NOxpäästöt

NOx-päästöt refer to nitrogen oxides released into the atmosphere, primarily nitric oxide (NO) and nitrogen dioxide (NO2). They are produced during high-temperature combustion in engines, power plants, and industrial processes.

NOx forms when nitrogen in air reacts with oxygen under conditions of high temperature, such as in internal combustion engines, turbines, and boilers. Diesel engines, gasoline engines, and coal- or oil-fired plants are typical sources. Mobile sources usually dominate urban NOx emissions, while stationary sources contribute significantly in industrial regions.

Health and environmental impacts are central to NOx concerns. Exposure can irritate the airways and worsen respiratory conditions such as asthma. NO2 contributes to the formation of ground-level ozone and fine particles, which affect human health and can reduce visibility. NOx also participates in acid deposition and nutrient enrichment of ecosystems. In urban areas, NOx contributes to smog and climate-relevant chemistry.

Measurement and regulation vary by region, but NOx is generally regulated as part of broader air quality and emission standards. Ambient limits for NO2 are common in many countries, and vehicle emission standards aim to limit NOx from cars, trucks, and buses. Industrial plants are subject to emissions controls and permitting requirements to keep NOx below permitted levels.

Reduction strategies include technological controls such as catalytic converters and selective catalytic reduction (SCR) for NOx in vehicles and power plants, lean-burn engine optimization, low-sulfur fuels, energy efficiency, and the use of alternative propulsion. Effective NOx management combines technology, fuel quality, and operational practices to improve air quality and reduce environmental impact.