Pollution is the addition of chemicals, particles or energy to the environment at a rate that exceeds its ability to be dispersed, diluted, decomposed, recycled or stored in some harmless form. Pollution threatens human health, ecosystems and some Earth systems processes like the climate. It affects all people, but particularly low-income and marginalized communities.
There are many different kinds of pollution, but the most common include air pollution (smoke from cars, burning fossil fuels to produce electricity and heat homes), water pollution (toxins leaching into soil or water bodies from industrial and agricultural practices), land pollution (contamination from mining, dumping toxic wastes and landfills) and noise pollution (roadway and aircraft noise, high-intensity sonar and plastic litter).
The biggest source of global chemical pollution is the production of pharmaceutical drugs, which use chemicals in their manufacturing process. Fortunately, companies can reduce their production of pollution by adopting more environmentally friendly practices, which can also save money. Some countries and cities use economic instruments to make businesses internalize the externalities of their pollution, including tariffs, Pigouvian taxes and cap and trade schemes.
Despite advances in environmental protection, pollution is still a widespread problem. Air pollution, in particular, kills nine million people a year globally. This is because it contributes to many serious diseases, including cardiovascular disease and lung disease. It also increases a person’s risk of developing neurodegenerative diseases, such as Parkinson’s and Alzheimer’s, and can cause osteoporosis in women. These effects tend to be concentrated in poorer communities, which are closer to polluting industries and dumpsites.