What is Nitrogen Oxide (NOx)?
Nitrogen oxide (NOx), are gases produced by high temperature combustion. In Alaska, NOx pollution problems can be from both natural and man-made sources. Nitrogen oxide gases are colorless and odorless. However, one common pollutant, nitrogen dioxide (NO2) along with particles in the air, can often be seen as a reddish-brown layer in the sky.
At normal air temperature oxygen and nitrogen gases in the air will not react with each other. However, when the heat of an internal combustion engine is added, the mixture of air and fuel produces a reaction with combustion temperatures high enough to drive heat reactions between atmospheric nitrogen and oxygen in the flame. This yields various oxides of nitrogen. In areas of high motor vehicle traffic, the amount of nitrogen oxides emitted into the atmosphere can be quite significant.
Where does NOx come from?
Nitrogen oxides are formed when fuel is burned in the combustion process. The primary man-made sources of NOx are fuel burning motor vehicles, residential sources, electric utilities, agricultural fertilization and industrial facilities that burn fuels. NOx can also be formed naturally by fires, lightning and soil emissions.
If you want to compare municipalities and boroughs in Alaska with respect to air quality and health-related information, visit the EPA's Air Compare website at http://www.epa.gov/aircompare/.
How can NOx affect my family and my community?
NOx can cause a wide variety of health and environmental impacts. Some environmental effects are:Visibility Impairment – Elders in Alaska Villages have said that there are times when the visibility in their community is so bad that they cannot tell the weather or see far away. When nitrate particles and nitrogen dioxide combine they can block the transmission of light, reducing visibility.
Smog - is formed when NOx and other compounds react in the presence of sunlight. Children, people with lung diseases such as asthma, and people who work or exercise outside are susceptible to adverse effects such as damage to lung tissue and reduction in lung function. Smog can be transported by wind currents and cause health impacts far from original sources.
Acid Rain - NOx and sulfur dioxide react with other substances in the air to form acids. These acids fall to earth as rain, fog, snow or dry particles. Some of the rain, snow or particles may be carried by wind for hundreds of miles. Acid rain damages the lakes and streams making them acidic and unsuitable for many fish.
Particles - NOx reacts with ammonia, moisture, and other compounds to form particles. Human health concerns include effects on breathing and the respiratory system, damage to lung tissue and premature death. Small particles penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease such as emphysema and bronchitis, and aggravate existing heart disease.
Water Quality Deterioration - Increased nitrogen loading in water bodies, particularly coastal estuaries, upsets the chemical balance of nutrients used by aquatic plants and animals. Additional nitrogen accelerates "eutrophication," which leads to oxygen depletion and reduces fish and shellfish populations.
Climate Change - One gas related to NOx is nitrous oxide(NO2), is a greenhouse gas. It accumulates in the atmosphere with other greenhouse gases causing a suspected gradual rise in the earth's temperature. This may lead to increased risks to human health, a rise in the sea level, and other adverse changes to plant and animal habitat.
A serious environmental problem is the complex photochemical reactions in the lower atmosphere between NOx and other pollutants, mainly hydrocarbons emitted into the atmosphere from the burning of fossil fuel, which cause the formation of photochemical smog. These pollutants can subsequently precipitate and contribute to what is generally referred to as acid rain.
Acid rain can have an adverse effect on both terrestrial and aquatic ecosystems. Exposure of plants to nitrogen oxides (NOx) causes leaf spotting and breakdown of plant tissue. The damage caused to plants affect their value as food.
Studies have found that during early spring when snow melts rapidly, nitrates and sulfates that have accumulated in the snow pass directly into lakes as acids. When a lake is subjected to acid deposition, its pH declines slowly until the buffering capacity of the water is depleted. When this happens, land and water ecosystems become severely impacted.
Health effects of NOx can be:
Irritation the lungs, bronchitis, pneumonia, pulmonary edema, and lower resistance to respiratory infections such as influenza.Another gas related to NOx, nitric oxide (NO), does not an irritate your lungs, but like carbon monoxide it has a high affinity towards blood hemoglobin and can reducing the oxygen in the blood system.
Short-term exposures (e.g., less than 3 hours) to low levels of nitrogen dioxide (NO2) may lead to changes in airway responsiveness and lung function in individuals with pre-existing respiratory illnesses. It can cause pulmonary edema and inflammation.
Long term exposures to NOx and the other gases related to NOx may lead to increased susceptibility to respiratory infection and may cause permanent alterations in the lungs and exposure to higher levels may cause large amounts of fibrous tissue to develop in the lungs making you unable to breathe. This can be a fatal condition that develops within 3-5 weeks after exposure. These effects are worse in children (5–12 years old).
What can I do to decrease NOx in my community and at home?
Nitrogen Oxide (NOx) and the pollutants formed from NOx can be transported over long distances, following the pattern of prevailing winds. This means that problems associated with NOx are not confined to areas where NOx are emitted. Therefore, controlling NOx is often most effective if done from a broader scale, rather than focusing on sources in one local area.Some things you can do on a community level to decrease NOx emissions are:
If practical, plug in your car if the temperature is +20 or below. Most of Alaska's worst pollution days often occur when the temperature is between 0 and +20, rather than when it is 30 or 40 below zero.
Under cold start conditions the vehicle engine has been turned off for some time and the catalytic converter (if the vehicle is so equipped) is cold. Emissions are higher when a cold engine is first started than after the vehicle is warmed up. This is because catalytic emission control systems do not provide full control until they reach operating temperature (EPA considers a cold start for a catalyst-equipped vehicle to occur after the engine has been turned off for one hour. For non-catalyst vehicles, a four-hour engine-off period distinguishes a cold start.) http://ntl.bts.gov/DOCS/mob.html.
Make sure your car is well maintained. Properly inflate your tires, travel at even speeds, and try not to leave your car idling or warm it up for more than a few minutes.
If possible remove studded tires as soon as the roads clear up in the spring, and travel at the posted speed on unpaved roads. This helps to keep the particulate levels down.
Keep up the maintenance on your snowmachine and other Off-Road Vehicles. Overall, engines emit the same volume of hydrocarbons and NOx as 1,000 cars, and as much CO as 250 to 500 cars.
If you use a timer or a power-saver on your plug-in appliances, you can help decrease electricity that can also add to pollution.
When using stoves or fireplaces, build smaller fires that burn hotter and cleaner.