adapted to HTML from lecture notes of Prof. Stephen A. Nelson Tulane University
- Photochemical Smog - brown air. (This is what we have in the U.S.) Results from exhausts from cars, buses and trucks.
- Nitrogen Oxide + Oxgen + Hydrocarbons + Sunlight -- > Ozone
- 6ppm ozone is deadly - We need ozone in stratosphere; at lower altitudes, however, it can kill.
- Sulfurous Fog- gray air.
- Dominantly from burning coal with a significant pyrite content. The fogs of London in the past were actually sulfuous fog. This type of smog is no longer common in London as a result of environmental regulations on burning coal.
In valleys or on the lee side of mountains, air inversion may occur. A warmer air mass moves above cooler air, trapping the cooler, denser air underneath and increasing the severity of air pollution. Los Angeles is a good example of this, where warm desert air from the east comes over the mountains to the east of Los Angeles and lies over the cooler Pacific Ocean air. The cooler air is trapped because it cannot rise through the less dense warm air above it, and the pollution in the cold air accumulates.
A similar situation arises
in mountain valleys where warm air overlies the colder air which
in the valleys.
Also, cities tend to form
featuers known as heat islands or dust domes, which tend to collect
air filled with pollutants, and help spread it out over nearby suburbs.
|Gases contributing to Anthropogenic Greenhouse Effect|
(% per year)
- Global Warming has been
extensively, and currently, a large percentage of the scientific
have reached a consensus on various issues related to global warming.
|Scientific Consensus on Global Warming|
|Added greenhouse gases add heat||90+%|
|Added gases are anthropogenic||90+%|
|Reduction of uncertainty will require a decade||90+%|
|Full recovery will require many centuries||90+%|
|Large stratospheric cooling||90+%|
|Precipitation will increase||90%|
|Reduction of sea ice||90%|
|Warming in arctic||90%|
|Rise in sea level||90%|
|Local details of global change||?|
|Tropical storms increase||?|
|Details of next 25 years||?|
- Carbon Dioxide (CO2): Roughly 60% of total
- Burning Fossil Fuels
- Methane (CH4): 15% of total
- Coal Mines
- Rice Paddies
- Subpolar Soil and Wetlands (Methane Hydrate)
A Collection of sites that NASA put together about global warming: http://gcmd.gsfc.nasa.gov/faq/globwarm.html