Internal combustion engine the atmosphere by the reaction of and volatile organic compounds in the presence of sunlight. Ground-level ozone is harmful to human health and the environment. Though the same chemical substance, ground-level ozone should not be confused with stratospheric ozone, or the ozone layer, which protects the earth from harmful ultraviolet rays. Carbon fuels contain sulfur and impurities that eventually produce sulfur monoxides (SO) and sulfur dioxide (SO) in the exhaust, which promotes acid rain. In the United States, nitrogen oxides, PM, carbon monoxide, sulphur dioxide, and ozone, are regulated as criteria air pollutants under the Clean Air Act to levels
Oil sands pyrene, and benzo(a)pyrene) and that these emissions had been previously unreported. The Alberta government computes an Air Quality Health Index (AQHI) from sensors in five communities in the oil sands region, operated by a "partner" called the Wood Buffalo Environmental Association (WBEA). Each of their 17 continuously monitoring stations measure 3 to 10 air quality parameters among carbon monoxide (CO), hydrogen sulfide (), total reduced sulfur (TRS), Ammonia (), nitric oxide (NO), nitrogen dioxide (), nitrogen oxides (NO), ozone (), particulate matter (PM2.5), sulfur dioxide (), total hydrocarbons (THC), and methane/non-methane hydrocarbons (/NMHC). These AQHI are said to indicate 'low