NOxpäästöihin

NOxpäästöihin, or NOx emissions, refer to the release of nitrogen oxides—primarily nitric oxide (NO) and nitrogen dioxide (NO₂)—into the atmosphere. These gases are formed when nitrogen and oxygen in the air react under high temperatures and pressures, a process that typically occurs in combustion engines, industrial furnaces, and power plants. NOx gases are key contributors to air quality problems, including smog formation and the creation of secondary pollutants such as ozone and particulate matter. They also play a role in the depletion of the ozone layer and in climate change due to their greenhouse gas potential.

The sources of NOx emissions are diverse. Automotive exhaust is a major contributor, especially in regions with heavy traffic. Industrial activities, such as steel production, plastics manufacturing, and chemical synthesis, release significant amounts of NOx during processes that involve high-temperature combustion or plasma. Natural sources such as lightning and biological activity in soils also emit small quantities of NOx.

Regulatory frameworks address NOx emissions through standards that limit permissible emission levels for vehicles, factories, and power stations. Many countries follow guidelines set by the European Union or the United States Environmental Protection Agency, which enforce both maximum outlet concentrations and average emission limits. Compliance is achieved through technologies such as selective catalytic reduction, exhaust gas recirculation, and the use of low‑NOx burners.

Measured NOx emissions are typically expressed in milligrams per megajoule (mg/MJ) or grams per second, and monitoring is essential for ensuring adherence to environmental standards. Continuous emission monitoring systems (CEMS) are widely employed in industrial facilities to provide real‑time data.

Efforts to reduce NOx emissions focus on cleaner combustion technologies, fuel switching to lower‑carbon options, and stringent regulation of industrial processes. Reducing NOx not only improves air quality and public health but also aligns with global climate goals by decreasing the atmospheric burden of reactive nitrogen species.