Air pollutionAir pollution is one of the most important environmental issues facing the planet today. Air pollution is not only devastating to the environment but also human health. Transportation, industrial processes, and domestic combustion emit harmful pollutants such as nitrogen dioxide and PM2.5 particulate matter. PM2. 5 refers to atmospheric particulate matter that has a diameter of fewer than 2.5 micrometers. Concentrations of PM2.5 are dangerously high in many countries around the world, especially in developing regions. In 2020, Delhi was the most polluted capital city in the world with an average PM2.5 concentration of 84.1 micrograms per cubic meter of air (μg/m³). This was more than eight times higher than the average PM2.5 concentrations in London that year. Exposure to PM2.5 levels above 55.5 μg/m³ is considered unhealthy and increases the likelihood of heart and lung problems. Pollutants like PM2.5 are responsible for millions of premature deaths every year globally.
Land pollutionLand pollution refers to the deterioration of the earth's surfaces through direct or indirect human activities. There are many causes of land pollution, including agricultural fertilizers, mining, and landfills. Humans produce huge volumes of solid waste every year, but much of this waste is landfilled or disposed of at open dumps. Some of the largest landfills in the world stretch hundreds of acres and store waste that can take centuries to fully decompose.
Deforestation is also a form of land pollution. When trees are cut down for developments the land below is no longer protected from the sun. Over time this land becomes barren, resulting in soil erosion and desertification.
Water pollutionWater pollution is mostly a result of land pollution from sources such as agricultural runoff and industrial and domestic wastewater. Poorly managed wastewater infrastructures mean vast volumes of untreated wastewater flows back into the environment, contaminating water supplies. This exposes billions of people to drinking water contaminated with human excrement and diseases like cholera and dysentery. Diseases from unsafe drinking water kill hundreds of thousands of people every year, especially in developing countries.
Marine life and ecosystems are also devastated by human-caused pollution. Plastic waste has gained considerable attention in recent years due to its damaging impacts on marine life. There are now billions of pieces of plastic in our oceans that, when combined, can be as big as a country. Oil spills also make global headlines for the devastating and long terms impacts they have on marine ecosystems.