Air And Water Pollution: Causes And Sources

Air and water pollution are pressing issues that affect the health of the planet and its inhabitants. Air pollution refers to the release of pollutants into the air, which are detrimental to human health and the planet. Water pollution, on the other hand, contaminates our rivers, seas, oceans, and other water sources, endangering the health of millions worldwide. Both types of pollution are largely caused by human activities, such as the burning of fossil fuels, industrial emissions, and agricultural practices, and have far-reaching consequences for the environment, social and economic development, and public health.

How do air and water become polluted?

Industrial and transportation pollution

Industrial activities have been a major source of water and air pollution since the 1800s. Industrial waste, including chemicals, acids, and animal byproducts, has historically contaminated waterways, leading to grossly contaminated water sources. Today, industrial activities continue to contribute to water pollution through the discharge of toxins, waste, and random junk directly into waterways. This includes contaminants such as chemicals, heavy metals, and plastics, which are carried by streams and rivers into bays, estuaries, and eventually the ocean.

Air pollution from industries is primarily caused by the burning of fossil fuels and industrial processes. Power plants and industrial facilities that burn fossil fuels emit various pollutants, including particulate matter (dusts, fumes, mists, and smokes) and gaseous pollutants (gases and vapors). While filtering and scrubbing methods are used to reduce particles and gases, there is currently no effective method to capture the greenhouse gas carbon dioxide. As a result, industrial emissions contribute to air pollution and the build-up of greenhouse gases, leading to climate change.

Transportation is another significant contributor to air pollution, with carbon dioxide (CO2) emissions from vehicles being a primary driver of global warming. The combustion of jet fuel in the aviation sector, for instance, releases CO2, NOx, and water vapour into the atmosphere. Emissions from large ships running on heavy fuel oil are also a concern, as they produce high levels of sulfur oxides (SOx), NOx, and fine particulate matter.

Road vehicles, particularly those using fossil fuels like gasoline and diesel, release carbon dioxide, contributing to the greenhouse effect and climate change. Additionally, emissions of black carbon, a component of PM2.5, have a warming effect on the atmosphere, disrupting natural weather patterns and increasing the frequency of extreme weather events. While public transportation systems like buses, trains, and trams have lower per capita emissions than private cars, they still contribute to air pollution, especially in urban areas with high populations of vehicles.

To address transportation-related air pollution, the Environmental Protection Agency (EPA) in the United States has implemented national programs and standards for fuels and vehicles. These initiatives aim to reduce emissions, improve air quality, and spur investments in clean vehicle and engine technology. The Ports Initiative, for example, focuses on developing environmentally sustainable port strategies, while also supporting economic goals.

Similarly, the SmartWay program helps the freight transportation sector improve supply chain efficiency and reduce greenhouse gas emissions. EPA labelling requirements on vehicles also provide consumers with information about fuel economy and emissions, empowering them to make environmentally conscious choices.

Contaminated water from one country entering another

Water pollution is the contamination of water bodies, including lakes, rivers, oceans, aquifers, reservoirs, and groundwater, which has a detrimental effect on their uses. It is usually the result of human activities. Transboundary pollution is a type of water pollution that occurs when contaminated water from one country spills into the waters of another. This can happen due to a disaster, such as an oil spill, or the gradual downstream movement of industrial, agricultural, or municipal waste.

Transboundary waters account for 60% of the world's freshwater flows, and a significant number of countries share these water resources. However, only eight countries have improved their cooperation with neighbouring governments on transboundary water resources between 2020 and 2023. This lack of cooperation and effective water management can lead to water pollution spreading across borders.

Water pollution in one country can have a significant impact on the receiving country, affecting both the environment and human health. For example, the Yamuna River in India is heavily polluted by sewage from New Delhi, with a fecal coliform count 10,000 times the safe limit for bathing. This river then flows into neighbouring Bangladesh, where it can contaminate their water sources and impact the health of the population.

Additionally, water pollution in developing countries can be exacerbated by a lack of access to clean water, poor infrastructure, and low levels of water security. Interventions to reduce water pollution in these countries include improving hazardous waste disposal, implementing air quality monitoring, and using water treatment technologies to remove pollutants.

To address the issue of contaminated water flowing from one country to another, governments need to improve their monitoring and cooperation regarding transboundary waters. By working together and sharing information, countries can better manage their shared water resources and prevent water pollution from spreading across borders.

Sewage and wastewater treatment

The main goal of sewage and wastewater treatment is to remove contaminants and produce an effluent that can be safely discharged into the environment or reused. Treatment plants employ different processes, ranging from decentralized on-site systems to centralized systems with extensive networks of pipes and pump stations.

Primary treatment involves removing suspended solids and aerating the wastewater to restore oxygen levels. This step eliminates about 60% of the solids. Secondary treatment removes more than 90% of the remaining solids. Advanced treatments may include tertiary processes with polishing and nutrient removal.

In many cities, sewage and stormwater are carried together in combined sewer systems to treatment plants. However, during heavy precipitation, these systems can overflow, resulting in untreated sewage flowing directly into water bodies. This poses a significant risk to public health and the environment. To address this issue, some cities are investing in separate storm and waste systems.

Interventions to reduce water pollution include limiting hazardous waste disposal, improving waste management practices, and implementing air quality monitoring to inform local actions during periods of high pollution. Additionally, the use of household water filters can help reduce the presence of harmful substances like arsenic in drinking water.

Fossil fuel power plants

Fossil fuels, including coal, oil, and natural gas, have been the primary energy source for over a century, meeting our energy needs for transportation, businesses, and homes. However, burning these fuels releases harmful pollutants into the air and water, causing significant environmental and health issues.

The combustion of fossil fuels in power plants also releases toxic particulate matter, carcinogens, and ultra-fine particles that can cause serious health issues. These include asthma, cancer, heart disease, and premature death. Certain communities, particularly those of color and low-income, bear a disproportionate burden of these health impacts, experiencing higher exposure to particulate matter and living in areas with elevated cancer risks due to nearby industrial activities.

Additionally, fossil fuel power plants contribute to water pollution. Oil spills, a significant consequence of fossil fuel extraction, transportation, and refining, can release massive amounts of oil into water bodies, as evidenced by the 2010 BP Deepwater Horizon spill in the Gulf of Mexico. These spills harm wildlife, destroy habitats, erode shorelines, and contaminate water sources. Furthermore, fracking, a process used to extract fossil fuels, utilizes substantial amounts of water, generating toxic wastewater containing arsenic, lead, chlorine, and mercury, which can further contaminate groundwater and drinking water sources.

The burning of fossil fuels in power plants also contributes to ocean acidification. The oceans absorb a significant portion of the emitted carbon dioxide, leading to changes in water chemistry (pH). This increase in acidity reduces the availability of calcium carbonate, a crucial substance for shell-forming marine organisms, impacting their growth and survival.

Oil spills

The cleanup of oil spills is challenging, and even with advanced scientific methods, it is difficult to remove 100% of the spilled oil. In some cases, cleanup activities can cause further harm, as seen in the aftermath of the Exxon Valdez oil spill in 1989, where high-pressure, hot-water hoses used for cleanup caused more damage than the oil itself. The Oil Pollution Act of 1990 established that those responsible for oil spills are liable for the costs of cleanup and restoration.

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