Nitrogénoxidek

Nitrogénoxidek, often collectively referred to as NOx, is a group of gaseous compounds composed of nitrogen and oxygen. The most common and significant examples in atmospheric chemistry are nitric oxide (NO) and nitrogen dioxide (NO2). Nitric oxide is a colorless gas, while nitrogen dioxide is a reddish-brown gas. These compounds are formed through various natural and anthropogenic processes. Natural sources include lightning strikes and microbial activity in soil. Anthropogenic sources are primarily associated with high-temperature combustion processes, such as those in internal combustion engines of vehicles and in power plants.

NOx plays a crucial role in atmospheric chemistry. Nitric oxide is readily oxidized in the atmosphere to nitrogen dioxide. Nitrogen dioxide is a key precursor in the formation of ozone (O3) in the troposphere, particularly in polluted urban environments. This photochemical reaction, driven by sunlight, contributes to the formation of smog. Furthermore, NOx compounds can participate in the formation of nitric acid (HNO3), which can be deposited onto the Earth's surface through wet or dry deposition, contributing to acid rain and eutrophication of ecosystems. The presence of NOx in the atmosphere has implications for air quality, human health, and environmental processes.