NITROGEN DIOXIDE

NITROGEN DIOXIDE

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JUST LIKE A GLASS BOWL - Radiation from the sun would be reflected out into space, but with more greenhouse gases in the atmosphere some radiated heat is absorbed and re-emitted back to earth just as if we lived in a greenhouse.

By far the biggest contributor to global warming after water vapour, is Carbon Dioxide. We cannot do much about water vapour where around 71% of the Earth's surface is water. But, the rate of evaporation is dependent on temperature, hence the other gases that contribute to the glass-like bubble we live in are very important.

Human activities such as agriculture, fuel combustion, wastewater management, and industrial processes are increasing the amount of nitrogen dioxide in the atmosphere.

COMMON CONFUSION

Nitrogen makes up 78% of the Earth’s atmosphere and is an inert gas which is colourless, odourless and tasteless. It is commonly used in the beverage industry in beer, wine and juice production. The gas is predominantly used to prevent oxidation which can affect the taste and quality of the beverage and is also used to dispense beer. In this form Nitrogen works for us.

There seems to be confusion over the difference between nitrogen and nitrous oxide (N2O), more commonly known as laughing gas. This is a misconception, as although they both contain the element nitrogen, they are two different gases.

Nitrogen is a molecule composed of two nitrogen atoms, while nitrous oxide is a chemical compound of two nitrogen molecules and one oxygen molecule.

N2O - Formula : 2 Molecules of Nitrogen with 1 Molecule of Oxygen.

Known as : Nitrous Oxide / Nitrogen Oxide / Dinitrogen Monoxide / Dinitrogen oxide

Colorless and non flammable. Used for a variety of things such as a pharmacological agent to produce anesthesia, a food additive as a propellant, and an additive to fuels to increase available oxygen in combustion.

NO2 - Formula : 1 Molecules of Nitrogen with 2 Molecule of Oxygen.

Known as : Nitrogen dioxide

Toxic by inhalation (vapor) and skin absorption. Noncombustible, but accelerates the burning of combustible materials.

The major source of nitrogen dioxide is the burning of fossil fuels: coal, oil and gas. Most of the nitrogen dioxide in cities comes from motor vehicle exhaust (about 80%). Other sources of nitrogen dioxide are petrol and metal refining, electricity generation from coal-fired power stations, other manufacturing industries and food processing.

Unflued gas heaters and cookers are the major sources of nitrogen dioxide in homes.

Nitrogen dioxide is an important air pollutant because it contributes to the formation of photochemical smog, which can have significant impacts on human health.

The main effect of breathing in raised levels of nitrogen dioxide is the increased likelihood of respiratory problems. Nitrogen dioxide inflames the lining of the lungs, and it can reduce immunity to lung infections. This can cause problems such as wheezing, coughing, colds, flu and bronchitis.

At higher temperatures it is a reddish-brown gas that has a characteristic sharp, biting odor and is a prominent air pollutant.

US ENVIRONMENTAL LIMITS

The U.S. EPA has set safety levels for environmental exposure to NO2 at 100 ppb, averaged over one hour, and 53 ppb, averaged annually. As of February 2016, no area of the US was out of compliance with these limits and concentrations ranged between 10–20 ppb, and annual average ambient NO2 concentrations, as measured at area-wide monitors, have decreased by more than 40% since 1980.

However, NO2 concentrations in vehicles and near roadways are appreciably higher than those measured at monitors in the current network. In fact, in-vehicle concentrations can be 2–3 times higher than measured at nearby area-wide monitors. Near-roadway (within about 50 metres (160 ft)) concentrations of NO2 have been measured to be approximately 30 to 100% higher than concentrations away from roadways. Individuals who spend time on or near major roadways can experience short-term NO2 exposures considerably higher than measured by the current network. Approximately 16% of U.S. housing units are located within 300 feet (91 m) of a major highway, railroad, or airport (approximately 48 million people).

AUSTRALIAN LIMITS

Through the National Environment Protection Council, the Australian, State and Territory Governments have also agreed on a National Environment Protection Measure for Ambient1 Air Quality. The Measure contains national standards for six key air pollutants in Australia, including nitrogen dioxide. (See fact sheet on National Standards for Criteria Air Pollutants in Australia). One of the aims of the Measure is to keep nitrogen dioxide in outdoor air below the following levels by the year 2008:

0.12 ppm (parts per million) over a one hour period
0.03 ppm averaged over a one year period.

These levels, when averaged over one hour or one year, have not been exceeded in any Australian capital city since the early 1990s.

GREENHOUSE GASES

The major greenhouse gases are water vapour, which causes about 36–70% of the greenhouse effect; carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; nitrous oxide (N2O) that accounts for about 5.6 percent of greenhouse gas emissions from human activities and ozone (O3), which causes 3–7%.

THE CAUSES IN SECTORS - Transportation and energy for living are the main causes of greenhouse gas build up in the atmosphere as carbon dioxide and nitrous oxides, with agriculture loading us with methane and more nitrous oxides. Hence, we need to revise our eating habits and switch to renewable energy for our cars and industry as quickly as possible.

The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in a planet's atmosphere, warm its lower atmosphere and surface, to include warming the oceans and melting the ice caps.

LINKS & REFERENCE

https://www.environment.gov.au/atmosphere/airquality/publications/standards.html

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