Biology - Pollution

Pollution is defined as any undesirable change in the physical, chemical, or biological characteristics of air, water, or soil that may harmfully affect life or create a potential health hazard.

Air Pollution: Major gaseous pollutants include Carbon Monoxide ($CO$), Sulfur Dioxide ($SO_2$), Nitrogen Oxides ($NO_x$), and Greenhouse gases like Carbon Dioxide ($CO_2$) and Methane ($CH_4$).

Acid Rain: Formed when $SO_2$ and $NO_x$ react with atmospheric moisture to form Sulfuric Acid ($H_2SO_4$) and Nitric Acid ($HNO_3$), resulting in rain with a $pH$ lower than $5.6$.

Greenhouse Effect and Global Warming: The trapping of solar radiation by gases like $CO_2$, $CH_4$, $N_2O$, and $CFCs$, leading to a rise in the Earth's average temperature.

Ozone Depletion: The thinning of the stratospheric ozone ($O_3$) layer due to Chlorofluorocarbons ($CFCs$), which release chlorine atoms that catalyze the breakdown of $O_3$ into $O_2$.

Water Pollution: Contamination of water bodies by sewage, industrial effluents, and agricultural runoff. Key indicators include Biological Oxygen Demand ($BOD$).

Eutrophication: The process of nutrient enrichment (Nitrates and Phosphates) in water bodies leading to excessive algal growth, depletion of dissolved oxygen ($DO$), and death of aquatic life.

Biomagnification: The increase in concentration of non-biodegradable toxic substances like $DDT$ or Mercury ($Hg$) at each successive trophic level in a food chain.

Noise Pollution: Measured in decibels ($dB$). Continuous exposure to noise above $80$ $dB$ can lead to hearing loss and psychological stress.