Nitrogen Dioxide's Harmful Impact On Air Quality

Nitrogen dioxide (NO2) is a gaseous air pollutant composed of nitrogen and oxygen. It is a member of the nitrogen oxides group of gases. NO2 is formed when fossil fuels such as coal, oil, gas or diesel are burned at high temperatures. It is a significant contributor to air pollution, particularly in large urban regions, and is associated with a range of adverse health effects, especially for those living near emission sources. NO2 is also harmful to vegetation and can react with surfaces.

Nitrogen dioxide is formed when fossil fuels are burned at high temperatures

Nitrogen dioxide (NO2) is a gaseous air pollutant composed of nitrogen and oxygen. It is one of a group of gases called nitrogen oxides (NOx) that are formed when fossil fuels are burned at high temperatures. Fossil fuels, such as coal, oil, gas, or diesel, are burned to generate electricity, power transportation, and for industrial processes.

The burning of fossil fuels releases nitrogen oxides into the atmosphere, which contribute to the formation of smog and acid rain. Acid rain can contaminate freshwater sources, leading to harmful algal blooms that reduce water oxygen levels and harm aquatic life. Additionally, the presence of excess nitrogen in the atmosphere, in the form of nitrogen oxides, can be deposited back onto land and wash into nearby water bodies.

Nitrogen dioxide is a significant contributor to air pollution, particularly in urban areas. Trucks, buses, and cars are the largest sources of NO2 emissions, with levels typically higher on or near heavily travelled roadways. Other sources include industrial processes such as oil and gas production, industrial boilers, and coal-fired power plants. The combustion of fossil fuels also releases other pollutants, including carbon monoxide, carbon dioxide, sulfur dioxide, and particulate matter, which further contribute to air pollution and have detrimental effects on human health and the environment.

The health impacts of nitrogen dioxide exposure are well-documented. Acute exposure to high concentrations of NO2 has been linked to respiratory issues and can cause a variety of adverse effects, including alterations to lung metabolism, structure, and function. People with pre-existing medical conditions, such as asthma, chronic obstructive pulmonary disease (COPD), and cardiovascular disease, are at an elevated risk of experiencing health complications from nitrogen dioxide pollution.

Long-term exposure to high levels of nitrogen dioxide can cause chronic lung disease

Nitrogen dioxide (NO2) is a gaseous air pollutant composed of nitrogen and oxygen. It is formed when fossil fuels such as coal, oil, gas, or diesel are burned at high temperatures. Trucks, buses, and cars are the largest sources of NO2 emissions, but it is also produced by burning natural gas (methane) and during industrial processes such as oil and gas production, and in coal-fired power plants.

In addition to the health risks, high levels of nitrogen dioxide are also harmful to vegetation, damaging foliage, decreasing growth, and reducing crop yields. It can also fade and discolour furnishings and fabrics, reduce visibility, and react with surfaces.

While everyone is at risk from the health impacts of nitrogen dioxide pollution, those who live near emission sources are at higher risk. Other vulnerable subpopulations include people with pre-existing medical conditions and people of colour. Infants and children are particularly at risk due to their higher breathing rate for their body weight and their typically greater outdoor exposure duration.

It is important to note that NO2 is just one of a group of gases called nitrogen oxides, and that it often reacts with other pollutants to form secondary pollutants, which are likely responsible for many adverse health effects.

Nitrogen dioxide is harmful to vegetation and can discolour furnishings and fabrics

Nitrogen dioxide (NO2) is a gaseous air pollutant composed of nitrogen and oxygen. It is formed when fossil fuels such as coal, oil, gas, or diesel are burned at high temperatures. NO2 is one of the two principal nitrogen oxides associated with combustion sources, the other being nitric oxide (NO). These gases are critical components of photochemical smog, which often has a yellowish-brown colour.

Nitrogen dioxide is harmful to vegetation. It is deposited into leaves via stomata, which can benefit air quality by providing an additional source of nitrogen for plants. However, high levels of NO2 in the air can negatively impact vegetation.

Nitrogen dioxide can also have adverse effects on human health. It is a strong oxidant, corrosive, and poorly soluble in water. It has a pungent odour and can cause damage to the human respiratory tract, increasing the severity of respiratory infections and the likelihood of asthma. Long-term exposure to high levels of NO2 can lead to chronic lung disease. Additionally, elevated levels of nitrogen dioxide, along with particulate matter and sulfur dioxide, have been linked to heart and lung harm, affected pregnancy and birth outcomes, and an increased risk of kidney and neurological harm, autoimmune disorders, and cancer.

Furthermore, nitrogen dioxide can discolour and fade furnishings and fabrics. It reacts with water and is soluble in sulfuric and nitric acids. In indoor environments, sources of nitrogen dioxide include tobacco smoke and gas-, wood-, oil-, kerosene- and coal-burning appliances, such as stoves, ovens, and heaters. Poor ventilation can lead to a buildup of NO2 to unhealthy levels.

It is important to note that efforts to reduce emissions of nitrogen dioxide have been successful in some regions, and air quality has improved over the years. However, many people still breathe unhealthy levels of nitrogen dioxide pollution, particularly those living near emission sources or in densely populated urban areas.

Nitrogen dioxide is a pungent gas that contributes to the reddish-brown haze of smog

Nitrogen dioxide (NO2) is a gaseous air pollutant composed of nitrogen and oxygen. It is a pungent gas that, along with fine airborne particulate matter, contributes to the reddish-brown haze characteristic of smoggy air. NO2 is formed when fossil fuels such as coal, oil, gas, or diesel are burned at high temperatures. Trucks, buses, and cars are the largest sources of NO2 emissions, followed by non-road diesel equipment, industrial processes, and coal-fired power plants. NO2 is also produced from burning natural gas (methane) both outdoors and indoors.

NO2 is one of a group of gases called nitrogen oxides, which also includes nitric oxide (NO). These two gases are the principal nitrogen oxides associated with combustion sources. NO2 is an important precursor of anthropogenic ozone (O3) and is a key agent in the formation of several airborne toxic substances, including nitric acid (HNO3), fine particles, peroxyacetyl nitrate, nitrosamines, and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs).

Long-term exposure to high levels of NO2 can have significant health impacts, including chronic lung disease. It may also affect the senses, reducing a person's ability to smell. Infants and children are particularly at risk due to their higher breathing rate for their body weight and greater outdoor exposure duration. Studies have shown that long-term NO2 exposure during childhood can lead to smaller lungs at maturity. Additionally, NO2 can injure vegetation, including trees, forests, and crops, and can react with and discolour surfaces.

NO2 levels are typically measured using instruments such as nitrogen oxides analysers, which employ techniques like differential optical absorption spectroscopy (DOAS). While NO2 emissions have decreased in recent years due to cleanup efforts, monitors still show high concentrations in large urban regions. As a result, many people continue to breathe unhealthy levels of NO2 pollution, particularly those living near emission sources or heavily travelled roadways.

Nitrogen dioxide is a marker for controlling ambient levels of NOx

Nitrogen dioxide (NO2) is a gaseous air pollutant composed of nitrogen and oxygen. It is formed when fossil fuels such as coal, oil, gas, or diesel are burned at high temperatures. NO2 is one of a group of gases called nitrogen oxides, or NOx. NOx is shorthand for nitric oxide (NO) and nitrogen dioxide (NO2), the nitrogen oxides most relevant for air pollution. These gases contribute to the formation of smog and acid rain and affect tropospheric ozone.

NO2 is a significant air pollutant, with human-made sources in the US emitting 7.64 million short tons of nitrogen oxides per year, mainly from burning fuels. Trucks, buses, and cars are the largest sources of NO2 emissions, but it is also produced from burning natural gas (methane) and by gas-fired power plants. NO2 levels in the air vary with direct emission levels and changing atmospheric conditions, particularly the amount of sunlight.

As NO2 is a precursor to several other air pollutants, including ozone (O3), nitric acid (HNO3), and nitrate (NO3-) particles, air quality regulators have selected it as a marker for controlling ambient levels of NOx. This means that by reducing NO2 emissions, the formation of other harmful pollutants can also be reduced. For example, NO2 is a key agent in the formation of toxic substances such as peroxyacetyl nitrate, nitrosamines, and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs).

The California Air Resources Board has set specific standards for NO2 emissions, with the state one-hour standard lowered to 0.18 ppm and the annual average standard retained at 0.030 ppm based on evidence of adverse health effects. The national standard for NOx emissions also considers NO2 levels as a marker for determining attainment.

It is important to note that while everyone is at risk from the health impacts of nitrogen dioxide pollution, those living near emission sources and vulnerable subpopulations are at higher risk. These vulnerable subpopulations include people with pre-existing medical conditions such as asthma, chronic obstructive pulmonary disease (COPD), cardiovascular disease, and people of color.

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