Summary of Introduction to Environmental Science

## Introduction Environmental pollution and conservation examine how human activities affect air, water, soil, ecosystems and climate, and what practical steps individuals and societies can take to reduce harm and protect nature. This material breaks down key problems, explains causes and consequences, and gives clear actions you can take even as a self-study student. ## 1. Main problems and their details ### 1.1 Air pollution > Definition: Air pollution is the contamination of the atmosphere by harmful gases, particles, or biological molecules that can endanger human health and the environment. - Sources: - Transport: cars, buses, trucks, airplanes, motorcycles produce exhaust gases that form smog. - Heavy industry: factories and power plants emit particulates and gases. - Domestic sources: heating, cooking with solid fuels. - Effects: - Smog reduces air quality and visibility; worsens respiratory illnesses. - Acid rain forms when sulfur dioxide reacts with rain (see section on acid rain). Practical example: A city with many diesel buses often experiences morning smog layers that increase hospital visits for asthma. ### 1.2 Acid rain > Definition: Acid rain is precipitation with elevated concentrations of hydrogen ions (low pH) from sulfur oxides and nitrogen oxides dissolved in rainwater. - Cause: Sulfur dioxide (SO2) and nitrogen oxides (NOx) from burning fossil fuels mix with rainwater. - Consequences: - Pollutes soils and fresh water bodies, harming aquatic life. - Damages forests, buildings, and cultural monuments. Real-world application: Reducing SO2 emissions from coal power plants lowers acidification of lakes and helps fish populations recover. ### 1.3 Water and soil pollution > Definition: Water and soil pollution occur when harmful substances (chemicals, waste, oil) enter water bodies or soils, making them unsafe for organisms and human use. - Sources: - Industrial and power-plant effluents dumped into waterways. - Household chemicals, improperly disposed oil, plastics and mixed waste. - Agricultural run-off with pesticides and fertilizers. - Effects: - Contaminated drinking water, damaged ecosystems, reduced soil fertility. Practical tip: Communities that treat wastewater and restrict industrial discharge see improved river health over years. ### 1.4 Ozone layer depletion > Definition: Ozone layer depletion is the thinning of the stratospheric ozone layer that normally absorbs harmful ultraviolet (UV) radiation from the Sun. - Cause: Chlorofluorocarbons (CFCs) and similar chemicals break down ozone molecules. - Consequences: - More UV radiation reaches Earth, increasing skin cancer risk and harming ecosystems. - Largest ozone hole historically observed over Antarctica and the Southern Hemisphere. Fact: International bans on many CFCs (Montreal Protocol) helped the ozone layer begin to recover. ### 1.5 Deforestation (Loss of rainforests) > Definition: Deforestation is the clearing of forested land for timber, agriculture, settlement, or plantations. - Why it happens: - Logging for wood and timber products - Converting land for agriculture or palm oil and soybean plantations - Clearing land for housing or roads - Consequences: - Loss of habitat for wildlife, reduced biodiversity - Less oxygen production locally, increased soil erosion - Disruption of water cycles and local climates Example: Conversion of tropical rainforest to palm-oil plantations can eliminate habitat for many endemic species and increase erosion during heavy rains. ### 1.6 Threats to wildlife > Definition: Threats to wildlife include any human-caused factors that reduce animal populations or damage habitats, leading to endangered species. - Main threats: - Poaching and illegal trade (trophies, skins, ivory) - Habitat loss from deforestation and urban expansion - Pollution and climate change altering habitats - Examples of endangered species: mountain gorilla, rhino, tiger, panda, certain