Greenhouse gases (GHGs) are gaseous components of the atmosphere that contribute to the greenhouse effect. Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases. Some of the main greenhouse gases due to anthropogenic activities are :

1. CO2 due to burning of the fossil fuels
2. Livestock and paddy rice farming, land use and wetland changes, pipeline losses, and covered vented landfill emissions leading to higher methane atmospheric concentrations.
3. use of CFCs in refrigeration systems, and use of CFCs and halons in fire suppression system

Cause of Ozone depletion, on other hand, is believed to be catalytic destruction of ozone by atomic chlorine and bromine. The primary source of these halogen atoms in the stratosphere is photodissociation of Chlorofluorocarbon (CFC) compounds, commonly called freons, and bromofluorocarbon compounds known as Halons, which are transported into the stratosphere after being emitted at the surface.

Acid rain is defined as any type of precipitation with a pH that is unusually low. It occurs when sulfur dioxide and nitrogen oxides are emitted into the atmosphere, undergo chemical transformations and are absorbed by water droplets in clouds. The droplets then fall to earth as acid precipitation. Carbondioxide (greenhouse gas) dissolves in atmospheric water vapor forming carbonic acid which also contributes towards acid deposition.

Anthropogenic role in these phenomena is quite evident. With the frequent use of refrigeration system we are the culprit in generation of non-biodegradable CFSs. These CFCs are the main factor for the destruction of ozone layer. Similarly greenhouse gas CO2 is produced in very large quantities through burning of fossil fuel in transportation and industrial activities. These carbondioxide is responsible for the formation of carbonic acid which contributes towards acid deposition.

Situations are slowly becoming alarming and it is really high time to replace CFCs by environment friendly substances substance like HCFCs. At the same time we have to start working on some eco-friendly techniques in which some biodegradable substances should be used. Similarly use of alternative source of energy will minimize the use of fossil fuel which in turn will reduce the acid deposition.

PFA