The term pollution comes from the Latin word ‘polluere’, which means contamination. Thus, in a simple language, pollution can be defined as the process of contaminating air, water, land, or other parts of the environment.
In the majority of cases, the components of pollution, called pollutants, are human-made substances and energies. While the quality of living has drastically improved in the recent decade, many new issues have arisen that directly or indirectly impact the environment and human health.
According to the World Health Organization, air pollution kills nearly 7 million people worldwide every year. And 9 out of 10 people breathe that contains harmful pollutants. This is just one form of pollution. There are many other forms that impact the ecological balance.
In this article, we have listed the 11 most common types of pollution along with their sources and significant impacts on human health and surroundings.
1. Air Pollution
Image credit: Pixabay
Major sources: Fossil fuel power stations, vehicle emissions, wildfires
Air pollution occurs when excessive quantities of harmful substances, particulates, and biological molecules are released into the atmosphere.
In the United States, outdoor air pollution measured as the Air Quality Index (AQI). It relies on concentrations of 5 major pollutants: particulate matter, ground-level ozone, sulfur dioxide, carbon monoxide, and nitrogen dioxide.
The indoor air pollution, on the other hand, mainly occurs dues to fuel-burning combustion appliances, tobacco products, and excess moisture.
It can cause severe health effects such as difficulty in breathing, asthma, heart disease, respiratory infections, and lung cancer. Some studies show that air pollution affects the central nervous system.
In addition to this, air pollution also causes global warming, ozone depletion, acid rain, and hazards to wildlife.
2. Water Pollution
Main sources: discharges of wastewater, untreated domestic sewage, and chemical contaminants into water bodies
Water pollution refers to the contamination of aquifers, groundwater, lakes, rivers, and oceans. Although most of the contaminants are introduced by human activities (such as oil spills and improper sewage treatment), natural processes like hypertrophication can also cause water pollution.
The 2 major types of water pollution are surface pollution (includes lakes, rivers, and oceans) and groundwater pollution. They are interrelated to each other: groundwater can feed surface water sources, and surface water seeps through the soil and becomes groundwater.
According to the National Oceanic and Atmospheric Administration, 80% of marine pollution comes from the land through sources like runoff. It affects both people living downstream and marine life.
Moreover, some man-made chemicals and substances deplete oxygen in the water, causing turbidity, which blocks sunlight, clogs the gills of some fishes, and disrupts the growth of plants.
3. Light Pollution
Before and during a massive power outage in Northeast that affected 55 million people (in 2003) | Image Credit: Todd Carlson
Major sources: Artificial light in the night environment
Light pollution, also called luminous- or photo pollution, is the excessive, obstructive or misdirected use of artificial outdoor lighting. Unlike other forms of pollution, it is largely overlooked and unregulated in many urban cities.
Over-illumination, light trespass, light clutter, and glare are the major categories of light pollution. In terms of energy wastage, lightning is responsible for at least 1/4th of global electricity consumption. It continues to grow as the demand for artificial light increases every year.
It eclipses natural starlight, interferes with astronomical observatories, and disrupts circadian rhythms of most organisms. There are many other adverse consequences but some of them are not known yet.
For example, artificial lights can disrupt activities of nocturnal animals, migration patterns of birds, developmental patterns of plants. Long exposure to humans can lead to sleep disorders and other health issues such as anxiety, medically defined stress, and increased headaches.
4. Noise Pollution
Traffic jam causing sound pollution in Delhi, India
Major sources: Road traffic, heavy machinery, and constant loud music near commercial venues
Intrusive and unnecessary sounds cause noise pollution. It influences mental and physical health of humans and other living organisms.
According to the World Health Organization, more than 8 hours of exposure to constant noise beyond 85 dB is hazardous. While old people could develop heart problems due to noise, children are especially vulnerable and the effects of noise that they have may be permanent.
Children living in regions with high aircraft noise have high stress and poor attention levels. Other sources of noise pollution (such as construction and workplace sounds) often cause sleep disturbances, hypertension, and hearing loss. A new study shows that it can also accelerate cognitive decline.
5. Plastic Pollution
Major sources: Plastic bottles and bags
Plastic pollution is the accumulation of plastic substances in the environment, which negatively impacts humans and wildlife habitat. These substances are often categorized into macro- or micro debris, based on size.
It has become one of the most critical environmental issues in developing African and Asian nations where garbage collection systems aren’t efficient.
While large plastic items take up to 1,000 years to decompose in the landfill, plastic bottles take 450 years and plastic bags take 10-20 years to decompose.
It not only affects land but also waterways and oceans. Up to 8.8 million metric tons of plastic waste is dumped into the ocean every year, and approximately 380 million tons of plastics are generated globally each year.
It mostly affects marine mammals and land animals. A substantial number of marine species have been found to contain excessive amounts of plastics in their stomachs. More than 100,000 marine creatures die annually due to plastic pollution in oceans.
6. Soil Contamination
Soil contamination due to excavation at gasworks in England | Wikimedia
Major sources: Heavy metals, petroleum hydrocarbons, and pesticides
Soil contamination is defined as the buildup of persistent toxic chemicals, salts, or disease-causing agents in soil, which has adverse effects on animal health and plant growth.
It mostly occurs because of human activities such as improper disposal of waste, spraying agricultural chemicals and industrial activity. The presence of excess chemicals increases the acidity or alkalinity of the soil, degrading its quality which further causes soil erosion.
Polluted soil increases health threats to people living on or nearby the degraded land. Its direct or indirect exposure can cause skin and respiratory diseases. It can also cause underground water contamination.
And since soil houses various types of microorganisms, reptiles, insects, and animals, these pollutants can alter the balance of the ecosystem of the soil.
7. Electromagnetic Pollution (Non-Ionizing Radiation)
Major source: Sunlight, cells phones, incandescent light bulbs, and far-infrared laser
The excessive quantity of electromagnetic radiation in its non-ionizing form can lead to burns. This includes near-ultraviolet radiation, microwave, radio waves, infrared, and black body radiation.
According to the World Health Organization, radiofrequency electromagnetic fields can cause cancer. So far, different biological effects have been recorded for different types of non-ionizing radiation. And a lot of research is being carried out worldwide.
Ionizing radiation is much more dangerous: it can even cause genetic damage. But since it is not as abundant as non-ionizing radiation, people are not constantly exposed to it.
8. Radioactive Pollution
The world’s first plutonium production reactor at the Hanford site, which represents 2/3rd of the US’ high-level radioactive waste by volume | Wikimedia
Major sources: Radionuclides (they emit gamma rays and beta particles)
Radioactive pollution, as per International Atomic Energy Agency’s definition, is the undesirable presence (or deposition) of radioactive compounds on surfaces of (or within) liquids, gases, or solids.
The radioactive chemical is released into the environment during production, testing and decommissioning of nuclear weapons, disposal of radioactive waste, mining of radioactive ores, mishaps at nuclear power plants and nuclear explosions.
Radioactive elements emit radiation: the higher their half-time, they lower the effects on human health. Elements with a short half-time, such as Uranium-232 which has a half-life of around 68.9 years, pose a serious threat to human health.
Following a nuclear reactor containment breach or an atmospheric nuclear weapon discharge, the soil, air, animals, and plants in the vicinity get contaminated by nuclear fuel and fission products. The Chernobyl disaster occurred in 1986 in the Ukrainian SSR is one of the most popular cases of widespread radioactive contamination.
9. Thermal Pollution
Image credit: Pixabay
Major sources: Wastewater generated by power plants and industrial manufacturers
Although the idea of thermal pollution doesn’t come to mind when thinking of pollution, it’s a real and persistent problem in our modern society.
Thermal pollution occurs when industries or organizations take water from natural sources and either heats it up or cools it down, and then eject it back into the natural resource.
Typically, power plants and industrial manufacturers use natural water as a coolant and eject it at a higher temperature. This variation in temperatures reduces oxygen level and affects ecosystem composition.
Aquatic organisms like juvenile fish, larva, plankton are sensitive to abrupt temperature change. Thus they can be killed by a sudden increase or decrease in temperature of water bodies, known as ‘Thermal shock’.
Soil erosion, deforestation, runoff from paved surfaces, and natural causes (like geothermal activity under the oceans or volcanoes) are other major factors that lead to thermal pollution.
10. Visual Pollution
Major sources: Too many billboards, electric wires, and cellphone towers
Visual pollution refers to something that blocks or obstructs the view of a particular thing or place. It’s an aesthetic issue, which means it impairs one’s ability to fully appreciate the view of a specific site.
Since different people likely have different opinions of what exactly constitutes visual pollution, it is difficult to define and measure the quantity of visual pollution.
Excessive amounts of open storage of trash, electric wires, billboards, and antennas are usually considered visual pollution. High-rise poorly planned buildings and Vandalism in the form of graffiti also add to visual clutter as they disturb the view.
Moreover, space debris also falls under a substantial level of visual pollution as it interferes with astronomical observations.
Image credit: China Smack
Major sources: Cigarette butts, fast-food packing
Litter is any kind of trash thrown where it doesn’t belong. In other words, improper disposal of waste products at an undesirable location (for example, throwing aluminum cans, cardboard boxes on the ground and leaving them there indefinitely) is called littering.
It is common to see people discarding fast-food packaging, used drink bottles, chewing gum wrappers on the road. Sometimes large items such as electrical appliances, batteries, tires, and industrial containers are dumped in isolated locations like national forests and other public lands.
Carelessness and laziness has bred a culture of habitual littering. And the belief that there are no consequences for littering has made it even worse.
Litter exists in the environments for several years before degrading, which significantly affects the quality of life. The major impacts involve the risk of fire hazards, the serious damages to waterways, the danger to public health, and endangering, or even killing wildlife.
The most littered item in the world is cigarette butts: about 4.5 trillion cigarettes are discarded every year. They leach toxic chemicals (such as lead and arsenic) into the environment. And since they contain plastic fibers, it takes 1.5 to 10 years for a cigarette filter to decompose, depending on environmental conditions like the sun and rain.