Oxides of Nitrogen: Health effects
Description
Low levels of oxides of nitrogen can irritate eyes, nose, throat and lungs, possibly leading to coughing, shortness of breath, tiredness and nausea. Exposure can also result in a build up of fluid in the lungs for 1-2 days after exposure. Breathing high levels of oxides of nitrogen can cause rapid burning, spasms and swelling of tissues in the throat and upper respiratory tract, reduced oxygenation of tissues, a build up of fluid in the lungs, and maybe even death.
Skin or eye contact with high concentrations of oxides of nitrogen gases or nitrogen dioxide liquid will likely lead to serious burns.
Entering the body
Oxides of nitrogen may be inhaled or absorbed through the skin.
Exposure
Most people are exposed to oxides of nitrogen by breathing in polluted air. People who live near combustion sources such as coal burning power plants or areas of high motor vehicle usage, or live in households that burn a lot of wood or use kerosene heaters or gas stoves may be exposed to higher levels of nitrogen oxides. Workers employed in facilities that use welding materials, produce nitric acid or certain explosives, may inhale oxides of nitrogen during their work.
Nitrogen dioxide and nitric oxide are found in tobacco smoke.
Health guidelines
Workplace exposure:
Currently, the eight-hour time weighted average (TWA) exposure limits are 31 milligrams of nitric oxide (NO) per cubic metre of air, 45 milligrams of nitrous oxide (N2O) per cubic metre of air and 5.6 milligrams of nitrogen dioxide (NO2) per cubic metre of air. A 15-minute short term exposure limit (STEL) has been established for NO2 at a level of 9.4 milligrams per cubic metre.
Australian drinking water guidelines:
In 2004, the National Health and Medical Research Council (NHMRC) and the National Resource Management Ministerial Council (NRMMC) established the following guidelines for acceptable water quality:
Based on health considerations, the concentration of nitrates should not exceed 50 milligrams per litre of drinking water for bottle-fed infants up to 3 months of age, up to 100 milligrams per litre of drinking water for adults and children over 3 months of age.
Where a water supply has between 50 and 100 milligrams of nitrate per litre of drinking water, active measures are required to ensure that those caring for infants are aware of the need to use alternative water sources in making up bottle feeds for infants under 3 months of age.
Based on health considerations, the concentration of nitrites should not exceed 3 milligrams per litre of drinking water.
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