Nitrogen oxides NO x react to form smog and acid rain. NO x reacts with ammonia, moisture and other compounds to form nitric acid vapour and related particles. The impacts of NO x on human health include damage to the lung tissue, breathing and respiratory problems. Nitric oxide NO is not considered to be hazardous to health at typical ambient conditions. However, excess nitric oxide and its products may cause respiratory ailments, hematologic side effects, metabolic disorders, low blood pressure, nausea, vomiting and diarrhoea.
Nitrogen dioxide NO 2 at high concentrations causes inflammation of the airways. Breathing in high levels of NO 2 can increase the likelihood of respiratory problems: wheezing, coughing, colds, flu and bronchitis. People with asthma are prone to have more intense attacks. Prolonged exposure to high levels of NO 2 can cause irreversible damages to the respiratory system. High levels of NOx can have a negative effect on vegetation by making it more susceptible to disease and frost damage.
When NOx reacts with other pollutants in the presence of sunlight, it forms ozone. Ozone at high concentrations also damage vegetation. Air pollution occurs when gases, dust particles, fumes or odour are introduced into the atmosphere which has harmful or poisonous effects. The common air pollutants are also known as criteria pollutants :.
The amount of nitrogen oxides emitted into the atmosphere as air pollution, from both man-made sources, can be quite significant. While NO 2 is a primary pollutant, it is also a contributing component for secondary pollutants formed from a chemical reaction.
The most common is ozone. Photochemical smog, most common in sunny, dry locations, is created when NO 2 from gas combustion is exposed to sunlight, splits and releases an oxygen ion O.
The released O combines with oxygen molecule O 2 forming ozone O 3. Ozone is one of the major secondary pollutants. You can read more about ozone pollution in our blog: Why do I have an ozone pollution problem and what can I do about it?
Indoor NO 2 levels are a result of both indoor and outdoor sources. While indoor NO 2 is produced by unvented heaters and gas stoves, high outdoor NO 2 levels originating from local traffic and other combustion sources can influence indoor levels. Air pollution is a serious problem and we should all be concerned. Worldwide, more deaths per year are linked to air pollution than to automobile accidents. NO 2 is both a primary and secondary pollutant.
Air pollution impacts everyone but some of us are more susceptible than others: children and seniors, people with existing lung and heart conditions, people working and exercising outdoors. Elevated levels of nitrogen dioxide can cause damage to the human respiratory tract and increase a person's vulnerability to, and the severity of, respiratory infections and asthma.
High levels of nitrogen dioxide are also harmful to vegetation—damaging foliage, decreasing growth or reducing crop yields. Nitrogen dioxide can fade and discolour furnishings and fabrics, reduce visibility, and react with surfaces.
Typical outdoor nitrogen dioxide levels are well below the 1-hour standard and exposure at these levels does not generally increase respiratory symptoms. This particular reaction is the oxidation of nitric oxide NO to nitrogen dioxide NO 2 by ozone O 3 as shown below:.
A photomultiplier tube measures the intensity of the emitted light. Since 1 NO molecule is required to form 1 NO 2 molecule, the intensity of the chemiluminescent reaction is directly proportional to the NO concentration in the sample.
The analyser measures the amount of light emitted and converts this to a concentration. A vacuum pump draws both the air supply for the ozone generator and the ambient air samples into the analyser. The green dot shows the ambient air sample path. A high-voltage corona discharge generates the ozone in dry air, shown in the diagram by the path of the red dot. Recommended for you. In Science magazine, scholars call for more comprehensive research into solar geoengineering 4 hours ago.
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