Environment of Pakistan
The Air pollution is the release of chemicals and particulates into the atmosphere. Common gaseous pollutants include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs) and nitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight. Particulate matter, or fine dust is characterized by their micrometre size PM to PM. The air in Karachi is rapidly polluted by automobile smoke, especially Rickshaws and Buses, industrial emissions, open burning of garbage, house fires, and other particles but the government and environment organizations seems non-serious to tackle the issue timely.
The two-stroke engines on rickshaws and motorcycles are one of the major polluters of air in Karachi and the rest of Pakistan. The two-stroke engines as well as defective or unturned vehicles are major polluters with carbon dioxide emissions. Two-stroke engines as well as defective vehicles using substandard lubricant are major emitters of sulfur dioxide and smoke. Automobiles operating on compressed natural gas and liquefied petroleum gas are major air polluters.
Criteria air pollutants
On December 2, 2009, the Center for Biological Diversity and 350.org requested that the EPA recognize that carbon dioxide and other GHGs are reasonably anticipated to endanger public health and welfare. Petitioners proposed that EPA list carbon dioxide as a criteria air pollutant, as outlined in the Clean Air Act. They also requested that the EPA set NAAQS for carbon dioxide at no greater than 350 ppm- a "level that accurately reflects the most recent scientific knowledge." Petitioners further requested that EPA designate the five other greenhouse gases, highlighted in Mass v. EPA, as criteria pollutants as well and establish pollution caps for them. Furthermore, the petitioners proposed that nitrogen trifluoride (NF) be regulated as a criteria air pollutant in addition to the other six.