Nitrogen oxides (NOx) are a group of gases composed of nitrogen and oxygen, primarily including nitrogen dioxide (NO2) and nitric oxide (NO). These gases are produced during combustion processes, such as in vehicles, power plants, and industrial facilities. They play a significant role in air pollution and can contribute to the formation of smog and acid rain. Exposure to nitrogen oxides can have harmful effects on human health, particularly for individuals with respiratory conditions like asthma. Additionally, NOx emissions can lead to environmental issues, as they can react with other pollutants to form ground-level ozone, which is detrimental to both ecosystems and public health.