Photochemical smog is a type of air pollution that is formed through the chemical reactions of pollutants in the presence of sunlight. It is typically characterized by the presence of high levels of ozone and other oxidants, as well as fine particulate matter. Photochemical smog is formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react with sunlight to form ozone and other oxidants. This process is known as the “photochemical reaction.”
The formation of photochemical smog is typically associated with urban areas and is influenced by factors such as the intensity of sunlight, temperature, and the presence of NOx and VOCs. Photochemical smog can have a range of negative effects on human health and the environment, including respiratory and cardiovascular problems, damage to vegetation and ecosystems, and reduced visibility.
There are a number of measures that can be taken to mitigate photochemical smog, including the reduction of NOx and VOC emissions from sources such as transportation, industry, and household products, the implementation of air quality regulations, and the promotion of alternative modes of transportation and cleaner fuels.
The 1999 Gothenburg Protocol is an international agreement under the United Nations Economic Commission for Europe (UNECE) that aims to reduce emissions of NOx and VOCs in order to reduce the formation of photochemical smog and improve air quality. The Protocol sets targets for the reduction of NOx and VOC emissions in a number of countries in Europe and North America, and provides a framework for cooperation and collaboration among Parties to achieve these targets.