Smog is just fog that has been polluted by hydroscopic nuclei, which contains chemicals and fumes. This makes the fog thicker and denser as there are far more particles. The atmospheric hydrocarbons from human activity account for only 15% of the total, but the effect they have is great because of where they are released - in urban areas. The biggest emitter of hydrocarbons is from car engines. As chemical reactions continue, the levels of ozone …showed first 75 words of 506 total…

…showed last 75 words of 506 total…have reduced vehicle emissions. But further reductions in vehicle emissions must occur before Californians can breathe clean, healthy air every day. By boosting efforts to detect and repair excessively polluting motor vehicles, the Smog Check II program is expected to reduce the total volume of smog-forming emissions from California's motor vehicles by about 100 tons per day this can be compared to the amount of ozone-forming emissions that is produced by californias power plants ------------------------------------------------------------------------ **Bibliography**