Nitrogen oxides (NOx) are a group of gases composed of nitrogen and oxygen, primarily produced from vehicle emissions and industrial processes. They play a significant role in air pollution and can contribute to the formation of smog and acid rain, impacting both human health and the environment. These gases can lead to respiratory problems and other health issues, particularly in vulnerable populations such as children and the elderly. Efforts to reduce NOx emissions include implementing stricter vehicle standards and promoting cleaner energy sources, which are essential for improving air quality and public health.