Monitoring atmospheric pollution

The choice of measuring equipment depends on a number of factors 

T)q)ical measures taken of the emissions include temperature, flow rates, particulates and the concentrations of pollutants. Various of the techniques are used are described below. 

Normally a mercury in glass thermometer is insufficiently robust and cannot be read remotely so are not generally used. 

The pitot tube is the standard method for measuring air velocity in ductwork and can accommodate the presence of solvent vapours and high temperatures. However, dust laden air may cause false readings. In use the head of the pitot tube must face into tfie gas flow. The standard pitot tube consists of a pair of concentric tubes. The inner tube has an open end that faces into the gas stream and measures the total gas pressure. The outer tube, which is sealed to the inner tube at its leading end has a series of holes at right angles to the gas flow that measure the static pressure of the gas. The tubes are connected to the opposite ends of a manometer that measures the differential pressure which is proportional to the gas velocity. 

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Guizard, S D. Chapoulard, M. Horani, and D. Gauyacq, Detection of NO Traces Using Resonantly Enhanced Multiphoton Ionization A Method for Monitoring Atmospheric Pollutants, Appl Phys. B, 48, 47f-477 (1989). 

The ratio of activities 131I/137Cs on 24 environmental filters from various parts of the UK averaged 9.1 (S.D.)0.9 (Stewart etal., 1961). This is less than half the ratio in the reactor fuel, allowing for the fact that the reactor had been virtually shut down for 4 d before the accident. The paper filters used in 1957 for monitoring atmospheric pollution... 

The chapter on Radioactive chemicals (Chapter 11) has been updated. Considerations of safety in design (Chapter 12) are presented separately from systems of work requirements, i.e. Operating procedures (Chapter 13). Tlie considerations for Marketing and transportation of hazardous chemicals are now addressed in two separate chapters (Chapters 14 and 15). Chemicals and the Environment are now also covered in two chapters (Chapters 16 and 17) to reflect the requirement that the impact of chemicals on the environment should be properly assessed, monitored and controlled. Although a substantial contribution to atmospheric pollution is made by emissions from road vehicles and other means of transport, and this is now strictly legislated for, this topic is outside the scope of this text. Chapter 18 provides useful conversion factors to help with the myriad of units used internationally. 

Jensen S, Eriksson G, Kylin H (1992) Atmospheric pollution by persistent organic compounds monitoring with pine needles. Chemosphere 24 229-245... 

The unique appearance of an infrared spectrum has resulted in the extensive use of infrared spectrometry to characterize such materials as natural products, polymers, detergents, lubricants, fats and resins. It is of particular value to the petroleum and polymer industries, to drug manufacturers and to producers of organic chemicals. Quantitative applications include the quality control of additives in fuel and lubricant blends and to assess the extent of chemical changes in various products due to ageing and use. Non-dispersive infrared analysers are used to monitor gas streams in industrial processes and atmospheric pollution. The instruments are generally portable and robust, consisting only of a radiation source, reference and sample cells and a detector filled with the gas which is to be monitored. 

In addition to the specificity of the monitoring method, an important requirement for the measurement of atmospheric pollutants is the accuracy of the calibration technique. The calibration procedure for the measurement of oxidants or ozone utilizes a stable and reproducible sample of dilute ozone in air. The ozone concentration of this sample is established with a reference method that is not necessarily suitable for monitoring ambient air. This reference method must agree with the scientifically accurate measurement of ozone in the calibration sample. 

Monitoring data have not shown cresols to be widely occurring atmospheric pollutants. The National Ambient Volatile Organic Compounds (VOCs) Database, a compilation of published and unpublished air monitoring data from 1970 to 1987, contained very little information on the cresols (Shah and Heyerdahl 1989). The database contained only information for o-cresol in source-dominated atmospheres (air surrounding a facility or known release of the chemical in question). The median air concentration of o-cresol at source-dominated sites is 0.359 ppb for 32 samples (Shah and Heyerdahl 1989). 

The CASTNET provides atmospheric data on the dry deposition component of total acid deposition, ground-level ozone, and other forms of atmospheric pollution. CASTNET is considered the nation s primary source for atmospheric data to estimate dry acidic deposition and to provide data on rural ozone levels. Used in conjunction with other national monitoring networks, CASTNET is used to determine the effectiveness of national emission control programs. Established in 1987, CASTNET now comprises over 70 monitoring stations across the United States. The longest data records are primarily at eastern sites. The majority of the monitoring stations are operated by EPA s Office of Air and Radiation however, approximately 20 stations arc operated by the National Park Service in cooperation with EPA. 

For gas-phase sensors, both remarkable selectivity and very low LOD are important. Sensors featuring MIP recognition combined with SAW transduction can meet these requirements. The MIP-PZ chemosensors operating in gases are devised for two main applications, namely for indoor gas inspection and online monitoring of volatile organic compounds. The latter is essential to protect humans from threats of environmental atmospheric pollutants. 

Nieboer, E. Richardson, D. H. S. (1981). Lichens as monitors of atmospheric deposition. In Atmospheric Pollutants in Natural Waters, ed. S. J. Eisemeich. Ann Arbor ... 

An example of a highly efficient interception system is the canopy of a coniferous forest. The large specific surface area of pine and spruce trees exceeds that of broadleaved deciduous trees, giving them a high scavenging efficiency for radioactive aerosol particles. Pine needles have been acknowledged as useful monitors of atmospheric pollution (Eriksson et al., 1989). However, radionuclides will be redistributed in the forest ecosystem due to various removal mechanisms such as rain... 

Eriksson, G., Jenson, S., Kylin, H. and Strachan, W., The pine needle as a monitor of atmospheric pollution. Nature, 341 (1989) 42-44. 

In devising a scheme for monitoring the rate of deterioration of the sandstone, the assumption was made that any effect that atmospheric pollutants may have on the stones integrity will appear at or near the surface. It is not a common occurrance that masonry is saturated throughout by water. Consequently, an adequate measure of erosion is the rate of recession of the surface. Here, the bonding material is dissolved or disrupted by repeated exposures to moisture which may contain chemicals which accelerate the process. The rate of recession is characterized by the rate at which the loosened quartz grains are subsequently removed. 

Carotta, M.C., et al., Nanostructured thick-film gas sensors for atmospheric pollutant monitoring Quantitative analysis on field tests, Sens. Actuators B Chem. 76 (2001) 336-342. 

Atmospheric chemistry, Air quality monitoring. Air pollution modelling. Atmospheric aerosol. Ozone... 

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