What is Pollution?
Pollution refers to the introduction of harmful substances or pollutants into the environment, resulting in adverse effects on ecosystems, human health, and the quality of air, water, and soil.
Common Pollutants
The World Health Organization (WHO) identifies six major air criteria pollutants, which are particularly harmful to human health. These pollutants include:
- Particle pollution (PM10 and PM2.5)
- Ground-level ozone (O3)
- Carbon monoxide (CO)
- Sulfur oxides (SOx)
- Nitrogen oxides (NOx)
- Lead (Pb)
Types of Pollutants:
Pollutants can exist in various forms, including solids, liquids, and gases. pollutants
Common include:
1. Solid pollutants
E.g. trash, plastics, and industrial waste.
2. Gaseous pollutants:
E.g. carbon monoxide, sulfur dioxide, and nitrogen oxides emitted from vehicles and industrial processes.
3. Liquid pollutants:
E.g. sewage, oil spills, and chemical runoff.
Sources of Pollution:
Industrial emissions
Vehicle emissions
Agricultural runoff
Residential activities
Key Concepts:
Eutrophication:
Bioaccumulation and Biomagnification:
Greenhouse Gases and Global Warming:
Point Source Pollution vs. Non-Point Source Pollution:
Greenhouse gases (GHGs) are gases in the Earth’s atmosphere that trap heat and contribute to the greenhouse effect, leading to global warming and climate change. Major greenhouse gases include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases. Human activities, such as burning fossil fuels, deforestation, and industrial processes, have significantly increased GHG concentrations in the atmosphere, causing global temperatures to rise and resulting in various climate-related impacts.
Bioaccumulation: This process occurs when pollutants accumulate in the tissues of organisms faster than they can be excreted or metabolized. As a result, the concentration of pollutants increases over time within the organism’s body. Bioaccumulation commonly affects aquatic organisms exposed to persistent pollutants like heavy metals and certain organic chemicals.
Biomagnification: Biomagnification refers to the process by which the concentration of pollutants increases at higher levels of the food chain. As organisms consume contaminated prey or food sources, the pollutants accumulate in their tissues. Consequently, predators at the top of the food chain, such as apex predators or humans, may experience higher levels of pollutant exposure due to biomagnification.
Point source pollution: This refers to pollution that originates from a single, identifiable source, such as a factory, power plant, or sewage treatment plant. Point source pollution can be easier to regulate and control because the source is localized.
Non-point source pollution: Unlike point source pollution, non-point source pollution comes from multiple, diffuse sources and is more challenging to trace back to specific origins. Examples include agricultural runoff, urban runoff, and atmospheric deposition. Non-point source pollution often results from activities such as agriculture, construction, and urban development.
Eutrophication is the excessive enrichment of water bodies with nutrients, primarily nitrogen and phosphorus. These nutrients originate from sources such as agricultural runoff, sewage discharge, and fertilizer use. In eutrophic waters, algae and aquatic plants proliferate, leading to algal blooms and oxygen depletion. This process can disrupt aquatic ecosystems, harm fish and other aquatic organisms, and degrade water quality, leading to ecological and economic impacts.
