Nitrogen's Role In Fighting Air Pollution

Nitrogen is an essential element for life on Earth, but it is also a major contributor to air pollution. Nitrogen dioxide (NO2) is a harmful gas and a major component of air pollution, which is formed by the combustion of fossil fuels such as coal, oil, and diesel. NO2 is a member of the nitrogen oxides (NOx) family of chemicals, which also includes nitric oxide (NO). NO2 is a pungent, reddish-brown gas with a strong smell. It contributes to the formation of other air pollutants, including ozone (O3), particulate matter, and acid rain.

NO2 has adverse effects on both human health and the environment. Exposure to NO2 can cause a range of harmful effects on the lungs, including increased inflammation of the airways, worsened cough and wheezing, reduced lung function, and increased asthma attacks. It can also lead to more serious health issues such as heart and lung damage, adverse pregnancy and birth outcomes, and an increased risk of cancer. Infants, children, the elderly, and individuals with pre-existing respiratory conditions are particularly vulnerable to the effects of NO2 pollution.

NO2 also has negative impacts on the environment. High levels of NO2 can harm vegetation, including trees, forests, and crops. It contributes to the formation of smog and reduces visibility by absorbing shorter blue wavelengths of light. Additionally, NO2 is a key contributor to climate change and the depletion of the ozone layer.

To address nitrogen pollution, it is essential to reduce emissions from fossil fuel combustion and improve nitrogen management practices in agriculture and industry.

Nitrogen pollution is a threat to human health

• Water containing elevated levels of nitrate, a form of nitrogen resulting from animal waste, plant decomposition, and fertiliser run-off, raises the risk of infants developing methemoglobinemia, commonly referred to as "blue baby syndrome", which can be fatal.
• High levels of nitrate in drinking water can also increase the risk of cancer in adults.
• Ammonia emissions, as well as contributing to climate change, are an important driver for fine particulate matter pollution, reducing air quality and increasing adverse health effects on humans.
• Nitrogen dioxide (NO2) is a gaseous air pollutant composed of nitrogen and oxygen. It is formed when fossil fuels such as coal, oil, methane gas, or diesel are burned at high temperatures. NO2 contributes to particle pollution and the chemical reactions that make ozone. Scientific evidence suggests that exposure to NO2 could likely cause asthma in children. A review of multiple studies found that elevated levels of NO2, along with elevated particulate matter and sulfur dioxide, were strongly associated with heart and lung harm, affected pregnancy and birth outcomes, and were likely associated with an increased risk of kidney and neurological harm, autoimmune disorders, and cancer.
• Nitrogen oxides (NOx) are formed by various combinations of oxygen and nitrogen at high temperatures during the combustion process. The higher the combustion temperature, the more nitric oxide is generated.
• Nitrogen oxides are also produced from burning natural gas (methane), both outdoors and indoors.
• Inhalation is the major route of exposure to nitrogen dioxide at room temperature. Direct contact with the eyes and associated membranes may lead to eye irritation.
• Nitrogen pollution is the most influential global driver of human-made biodiversity decline after habitat destruction and the emission of greenhouse gases.

Nitrogen pollution is a key contributor to climate change

When nitrogen in its active form is exposed to soil, microbial reactions release nitrous oxide, a gas 300 times more potent than carbon dioxide at warming the atmosphere. This gas remains active in the atmosphere for over 100 years. Fertilizer run-off can also cause algal blooms in lakes and waterways, which further emit greenhouse gases.

Agricultural ammonia emissions, though not a greenhouse gas, contribute to climate change. Ammonia is a gaseous form of nitrogen emitted into the atmosphere from the housing, storage, and spreading of animal manure and synthetic fertilizers. When released into the air, ammonia acts as a base for nitrous oxide emissions.

Fossil fuel and biomass combustion processes release nitric oxide and nitrogen dioxide, collectively called NOx. While efforts have been made to reduce NOx from vehicles and energy generation, emissions continue to rise in rapidly developing parts of the world. NOx is an indirect greenhouse gas as its deposition results in natural ecosystems emitting more nitrous oxide.

According to the 2018-2019 Frontiers Report by the United Nations Environment Programme, nitrogen costs the global economy between $340 billion and$3.4 trillion annually when accounting for its impact on human health and ecosystems.

Nitrogen dioxide is a harmful air pollutant

Nitrogen dioxide (NO2) is a harmful air pollutant that is formed when fossil fuels such as coal, oil, methane gas, or diesel are burned at high temperatures. It is a reddish-brown gas with a pungent odour and is one of the six widespread air pollutants for which there are national air quality standards. NO2 is one of the nitrogen oxides (NOx) that are formed during the combustion process, with the others being nitric oxide (NO).

• Increased inflammation of the airways
• Worsened cough and wheezing
• Reduced lung function
• Increased asthma attacks
• Greater likelihood of emergency department and hospital admissions
• Likely cause of asthma in children
• Increased risk of heart and lung harm, affected pregnancy and birth outcomes, and increased risk of kidney and neurological harm, autoimmune disorders and cancer

Nitrogen dioxide is particularly harmful to infants and children, who have a disproportionately higher exposure to NO2 than adults due to their greater breathing rate for their body weight and their typically greater outdoor exposure duration. It can also lead to smaller lungs at maturity in children with higher levels of exposure. In addition, people with chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease are at greater risk.

Nitrogen pollution is caused by human activity

Nitrogen pollution is a pressing issue, threatening the environment, human health, and the economy. Human activity is responsible for most of the reactive nitrogen that ends up as pollution.

Agriculture

The production of nitrogen-based fertilizers has doubled since 1978, with almost half of the world's population now relying on them for food production. The use of fertilizers has led to an increase in nitrates in water, which can be harmful even at low levels. Infants are particularly vulnerable to nitrate-contaminated drinking water, which can lead to "blue baby syndrome".

Fossil Fuels

The burning of fossil fuels for agriculture, transport, industry, and energy also contributes to nitrogen pollution. Nitrogen dioxide (NO2) is a harmful air pollutant that forms when fossil fuels are burned at high temperatures. NO2 contributes to particle pollution and the formation of ozone in the atmosphere. It can cause a range of respiratory issues, including increased inflammation of the airways, worsened cough and wheezing, and increased asthma attacks.

Livestock

Livestock waste is another source of nitrogen pollution, with the sector emitting 65 teragrams of nitrogen per year.

Wildfires

Wildfires and the burning of forests can increase emissions of nitrogen oxide (NO) and nitrous oxide (N2O), which are harmful to the environment and human health.

Nitrogen pollution can be mitigated through sustainable nitrogen management

Nitrogen is an abundant element in the Earth's atmosphere. It is a primary nutrient essential for the survival of all living organisms. However, excess nitrogen in the environment, especially in its reactive form, is hazardous and contributes to air pollution. The United Nations Environment Programme (UNEP) has identified nitrogen pollution as one of the most pressing pollution issues facing humanity.

Nitrogen pollution is primarily caused by the use of synthetic fertilizers, the discharge of wastewater, and the combustion of fossil fuels. It has detrimental effects on water, soil, and air quality and exacerbates climate change. To address this issue, the UNEP has adopted resolutions and initiatives aimed at sustainable nitrogen management. These include the UN Decade on Ecosystem Restoration (2021-2030), which aims to prevent, halt, and reverse the degradation of ecosystems, and the UNEA-4 "Resolution on Sustainable Nitrogen Management", which provides recommendations for protecting air and water quality, biodiversity, food sustainability, and economic recovery.

Sustainable nitrogen management involves improving nitrogen use efficiency (NUE) in food production to decrease the surplus of reactive nitrogen released into the environment. This can be achieved through various measures, such as substituting manure nitrogen for chemical fertilizer nitrogen, applying controlled-release fertilizers, and using urease inhibitors. Additionally, knowledge transfer to farmers and the adoption of new technologies are crucial for enhancing agricultural production efficiency.

Furthermore, a coordinated and collaborative approach is necessary for effective nitrogen management. This includes sharing best practices, promoting training and capacity building for policymakers and practitioners, and supporting member states in knowledge sharing. By implementing sustainable nitrogen management practices, we can mitigate nitrogen pollution, protect ecosystems, and ensure the sustainable use of this vital element.

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