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.
Pollution
The emergence of great factories and consumption of immense quantities of coal gave rise to unprecedented air pollution and the large volume of industrial chemical discharges added to the growing load of untreated human waste. Chicago and Cincinnati were the first two American cities to enact laws ensuring cleaner air in 1881. Pollution became a major issue in the United States in the early twentieth century, as progressive reformers took issue with air pollution caused by coal burning, water pollution caused by bad sanitation, and street pollution caused by the 3 million horses who worked in American cities in 1900, generating large quantities of urine and manure. As historian Martin Melosi notes, The generation that first saw automobiles replacing the horses saw cars as "miracles of cleanliness.". By the 1940s, however, automobile-caused smog was a major issue in Los Angeles.