"Among the most common air pollutants and their effects are: carbon monoxide (CO), generated mainly by burning fuel in vehicles and engines. Inhaling it reduces the amount of oxygen in the body's organs and tissues, aggravates heart disease, causes chest pain, among other symptoms. (4) Ozone (O3), a secondary pollutant formed by the chemical reaction of volatile organic compounds (VOC) and nitrogen oxides (NOx) in the presence of sunlight, decreases lung function and causes respiratory symptoms such as coughing and shortness of breath, causes asthma and worsens other lung diseases. (5) Nitrogen dioxide (NO2) is generated by the burning of fuel (from electricity companies, large industrial boilers and by vehicles) and the burning of wood, its inhalation aggravates lung diseases that cause symptoms of respiratory problems and increases the susceptibility to respiratory infection. (6) Also, by the particles (PM10 and PM2.5) that are formed through chemical reactions, from combustion (for example, the burning of coal, wood, diesel, gasoline), industrial processes, agriculture (plowing, field burning), and during road construction and in erosive processes and the extraction of stone material. Short-term exposures make heart or lung disease worse and cause breathing problems; and long-term exposures, heart or lung disease. (7) Another pollutant, sulfur dioxide (SO2), comes from the ignition of fuels (especially coal with high sulfur content), power companies and industrial refining processes, its inhalation aggravates asthma and makes breathing difficult ."