Nitrogen dioxide standards

NO Abatement. Source performance standards for nitric acid plants in the United States were introduced by the U.S. EPA in 1971 (55). These imposed a discharge limit of 1.5 kg of NO as equivalent nitrogen dioxide per 1000 kg of contained nitric acid, which corresponds to about 200—230... 

Sources Draft Air Quality Criteria for Oxides of Nitrogen, U.S. Environmental Protection Agency, Research Triangle Park, NC, 1981 Review of the National Ambient Air Quality Standard for Nitrogen Dioxide, Assessment of Scientific and Technical Information, EPA-450y 5-82-002. U.S. Environmental Protection Agency, Research Triangle Park, NC, March 1982. 

Abbott studied the corrosion of contacts, and proposed quality tests in dilute mixtures of hydrogen sulphide, nitrogen dioxide and chlorine in air at controlled temperature and humidity . These gave good results in a project seeking improved procedures for British and lEC standards . 

In the manufacture of nitric acid by the oxidation of ammonia, the first product is nitric oxide, which is then oxidized to nitrogen dioxide. From the standard reaction enthalpies... 

Nitrogen Dioxide. At Merced Station, located in the central region, the Standard was exceeded on 19 days from October 1988 to April 1989. In the same period, the Standard was exceeded 12 days at Tlalnepantla Station (northwest), and 3 days at Pedregal Station (southwest). 

Our analysis of the reaction of nitrogen dioxide molecules is not unique. The same type of path can be visualized for any chemical reaction, as Figure 6-20 shows. The reaction enthalpy for any chemical reaction can be found from the standard enthalpies of formation for all the reactants and products. Multiply each standard enthalpy of formation by the appropriate stoichiometric coefficient, add the values for the products, add the values for the reactants, and subtract the sum for reactants from the sum for products. Equation summarizes this procedure ... 

Figure L Calibration plot for nitrosation potential showing amount of t -nitroso-thiomorpholine formed vs, the square of the nitrogen dioxide concentration. Standard conditions of 50%relative humidity, 25°C, and 1 L/min flow rate for 30 min...

The technol( for the routine measurement of the nitrogen oxides (nitrogen dioxide and nitric oxide) is fairly well advanced. The epa is on the verge of officially proposing that chemiluminescence produced by the reaction of nitric oxide with ozone be the reference method for nitrogen dioxide.This method is even more suitable for nitric oxide. Because no national air quality standard has been promulgated for nitric oxide, no reference method will be specified. However, its measurement in the atmosphere is crucial for establishing the relation of its emission to the formation of atmospheric ozone and other photochemical oxidants. 

The calibration of a chemiluminescent analyzer using these standards is verified when both the nitrogen dioxide and nitric oxide channels respond similarly to charges from the (ylinder of diluted nitric oxide. Agreement with the response of the nitric oxide channel should also be obtained when the standard nitric oxide mixture is titrated with a previously established source of ozone. Chemiluminescent instruments have simplified monitoring of nitrogen oxides, but accurate calibration requires well-trained personnel. 

Consider the following example. Using information from the SQA Data Booklet and the fact that silver(l) nitrate and nitrogen dioxide have S° values of 142 and 241J K mol respectively, calculate the standard entropy change, AS°, for the decomposition of silver(l) nitrate ... 

National Institute for Occupational Safety and Health Criteria for a Recommended Standard... Occupational Exposure to Oxides of Nitrogen (Nitrogen Dioxide and Nitric Oxide). DHEW (NIOSH) Pub No 76-149, pp 76-85. Washington, DC, US Government Printing Office, 1976... 

State of California Air Resources Board Short-Term Ambient Air Quality Standard for Nitrogen Dioxide. Sacramento, CA, 1985... 

Sofia, Athens, Turin, and Barcelona, all in south Europe, exhibit the highest concentrations of total suspended particulates, above the WHO standard value. Concerning sulfur dioxide, all the cities presented exhibit concentration values below the standard set by WHO. In contrast, nitrogen dioxide is a cause for concern in many European cities, since values close to or above WHO standards are common. For this compound, cities in northern Europe also have to be on alert. 

It is useful to recollect the limits set by WHO 90 pg/m3 for total suspended particulates, 50 pg/m3 for sulfur dioxide, and 50 pg/m3 for nitrogen dioxide. It is apparent that the world has a long way to go till compliance with these numbers is achieved. Mexico City is notorious for bad ah quality. Pollution levels exceed WHO standards 350 days per year. More than half of all children in the city have lead levels in their blood sufficient to lower intelligence and retard development. The 130,000 industries and 2.5 million motor vehicles spew out more than 5500 metric tons of ah pollutants every day, which are trapped by the mountains tinging the city. 

For specific air pollutants, even some air pollutants in the National Ambient Air Quality Standard (e.g., nitrogen dioxide and particulate matter), the highest exposures may not occur outdoors. 

As mentioned in the introduction, the concentration of NO in Japan has remained almost constant for the last 10 years and often exceeds the air quality standard set for nitrogen dioxide (N02), particularly along heavy traffic roads in densely populated areas. To counter this situation, the development of a new technology for removing NO at sub-ppm level from air cf traffic roads, tunnels or other environmental emission sources is essential. 

The standard free energy of formation of a substance measures its thermodynamic stability with respect to its constituent elements. Substances that have a negative value of AG°f, such as carbon dioxide and water, are stable and do not decompose to their constituent elements under standard-state conditions. Substances that have a positive value of AG°f, such as ethylene and nitrogen dioxide, are thermodynamically unstable with respect to their constituent elements. Once prepared, though, such substances can exist for long periods of time if the rate of their decomposition is slow. 

In spite of the new vehicle emission EUROx regulations, 20% of Europe s urban population is also living in areas where the atmospheric concentrations of nitrogen dioxide (N02) exceed established air quality standards [18]. This is due to several factors related to the diesel-powered cars [19] (1) their increasing market penetration across Europe [20] (2) the NO emission factors of diesel cars exceed the emission levels as established during the type approval of these vehicles in the laboratory [19, 21-25] and (3) the fraction of N02 in the NO emissions of diesel... 

Gas standards for the calibration of air quality monitors containing sulphur dioxide, nitrogen monoxide or nitrogen dioxide at ambient concentrations. 

W.C. Cooper, I.R. Tabershaw, Biologic effects of nitrogen dioxide in relation to air quality standards. Arch. Environ. Health. 10 455, 1965. 

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