Aerosols particles, atmospheric contaminant

The NO + 03 chemiluminescent reaction [Reactions (1-3)] is utilized in two commercially available GC detectors, the TEA detector, manufactured by Thermal Electric Corporation (Saddle Brook, NJ), and two nitrogen-selective detectors, manufactured by Thermal Electric Corporation and Antek Instruments, respectively. The TEA detector provides a highly sensitive and selective means of analyzing samples for A-nitrosamines, many of which are known carcinogens. These compounds can be found in such diverse matrices as foods, cosmetics, tobacco products, and environmental samples of soil and water. The TEA detector can also be used to quantify nitroaromatics. This class of compounds includes many explosives and various reactive intermediates used in the chemical industry [121]. Several nitroaromatics are known carcinogens, and are found as environmental contaminants. They have been repeatedly identified in organic aerosol particles, formed from the reaction of polycyclic aromatic hydrocarbons with atmospheric nitric acid at the particle surface [122-124], The TEA detector is extremely selective, which aids analyses in complex matrices, but also severely limits the number of potential applications for the detector [125-127],... 

NH3 and to a lesser extent mono-, di-, and trimethylamines are the only significant gaseous bases in the atmosphere, and there has been considerable interest in whether the oceans are a source or sink of these gases. Early attempt to assess the air-sea flux from concentration measurements are probably suspect because of the ease with which sample contamination can occur during laboratory processing and analysis. It should be noted here that due to its high solubihty (low value of Henry s law constant), the air-water transfer of NH3 (and the methylamines for the same reason) is under gas phase control (see Section 6.03.2.1.1). The first reliable measurements were probably from the North and South Pacific and indicated that the flux of NH3 from sea to air is of a size similar to that for emission of DMS (Quinn et al., 1990, 1988). Indeed, the authors showed that this similarity was mirrored in the molar ratio of (non-sea-salt) sulfate to ammonium (1.3 0.7) in atmospheric aerosol particles collected on the cruise, indicating that for clean marine air remote from terrestrial sources, the emission of DMS and NH3 from the sea appears to control the composition of the aerosol. 

It has been argued that the Kqa values can be used as a unifying property for describing volatilization of POPs from soils and sorption to aerosols. The limited experimentally obtained values typically are supplemented by estimates from octanol-water and air-water partition coefficients. The value of condensation temperature lies in its ability to estimate sorption of atmospheric contaminants to aerosols (Bidleman, 1988). At Tc, the chemical is equally partitioned between the gas phase and aerosols. Since POPs exist in the atmosphere both as gases (vapor phase), and in condensed form adsorbed to aerosol particles, the characteristic temperature of... 

The description of a number of meteorological phenomena is also based on the study of Brownian diffusion of aerosols to single solid and liquid particles. The increasing atmospheric pollution is a problem that requires understanding and description of the processes of atmospheric self-purification of chemical and mechanical pollutants and radioactive contaminants. The problem of settling aerosol particles on various collectors also arises in the analysis of filter efficiency. 

Kiss G, Varga-Puchony Z, Hlavaj Z (1996) Distribution of polycyclic aromatic hydrocarbons on atmospheric aerosol particles of different size. In Kulmala M, Wagner PO (eds) Nucleation and atmospherie aerosols 1996. Elsevier, Kidlington, pp 501-503 Klein GP, Hodge EM, Diamond ML, Yip A, Dann T, Stem G, Denison MS, Harper PA (2(X)6) Gas-phase ambient air contaminants exhibit significant dioxin-like and estrogen-like activity in vitro. Environ Health Perspect 114 697—703... 

These insights indicate that the presence of excess iodine, chlorine, fluorine and, to a lesser extent, bromine, on the surfaces of Antarctic stony meteorites is attributable to the deposition of aerosol particles (Cl, F, Br) and of methyl iodide from the atmosphere. In other words, the excess halogens on the surfaces of Antarctic meteorites are atmospheric contaminants rather than weathering products. Accordingly, the amount of excess iodine on a meteorite lying on an Antarctic ice field increases primarily as a function of time and is less dependent on the climatic conditions on the ice field and on its distance from the coast. 

The terrestrial component of the dust particles embedded in the ice consists of volcanic ash, finegrained dust derived from soil on the continents, carbon particles released by forest fires, biogenic particles (e.g., the skeletons of diatoms, seeds, and pollen grains), aerosol particles of atmospheric origin, including sea-spray particles that nucleate snow flakes (Section 17.10). In addition, the uppermost layer of snow and fim that was deposited after the start of the Industrial Revolution (i.e., post ad 1850) contains anthropogenic detritus such as flakes of metal, paint, and plastics, fly-ash particles and other combustion products, fibers (composed of wood, cotton, and synthetics), industrial contaminants (e.g., lead), and radioactive nuchdes released by the testing of nuclear weapons and by the operation of nuclear reactors (Faure et al. 1997). 

Subsequently, similar phenomenon was discovered in troposphere [23-25]. The distinction was the following in troposphere, the most centers of nucleation were represented by the charged fragments of molecules of industrial contamination (nitric oxides, ammonia, sulphuric acid and so on). It was obvious that ions play an important role in the production of new aerosol particles (first of all, water nano- and microdrops) in atmosphere. But the problem of stability of the charged water nanodrops is not solved up to now. 

Chemical contaminants in the atmosphere can be deposited to surfaces in association with aerosol particles or falling rain and snow. These are advective transport processes, since the chemical moves in association with aerosol particles, raindrops, or snowflakes. This chapter describes methods for estimating chemical fluxes associated with deposition of aerosol particles and precipitation, and provides recommended values for mass transfer coefficients for a range of environmental conditions. In this chapter we do not consider transport of gaseous species in the atmosphere and adjacent surfaces. These convective transport processes, termed dry deposition of gases, are covered in Chapter 2, Section 2.5.6 and Chapter 7, Section 7.3. exchange between air and plants in Chapter 7, air and water in Chapter 9, and air and snow in Chapter 18. 

For use with receptor models, it is desirable to collect particles far enough from the source to allow the emissions to reach equilibrium with the atmosphere, but not so far away that the source material under test becomes contaminated with aerosol from other sources. 

Air quality in homes and workplaces is affected by human activities, construction material, underground minerals, and outside pollution. The most common indoor pollutants are radon, carbon oxides, nitrogen oxides, tobacco smoke, formaldehyde, and a large variety of organic compounds. Indoor atmospheres can also be contaminated with fine particles such as dust, aerosols (from spray cans), fungal spores, and other microorganisms. 

Gases are generally the easiest type of media to use because the contaminants in the test atmosphere are in the gaseous phase. Technically, aerosols include any liquid- or solid-phase material that forms a stable suspension in air. Dusts are solid-phase (contaminant) particles suspended into a gaseous (atmosphere) phase. They are generally the most difficult to use when conducting a study. 

Atmospheric conditions and particle size determine the persistence of aerosolized toxin in the environment. Temperature and humidity extremes facilitate toxin degradation, and smaller particles dissipate more quickly into the atmosphere. Studies estimate that aerosolized toxin would decay between less than 1 and 4% per minute. At a 1% decay rate, insubstantial amounts of toxin would remain after 2 days (36). Although botulinum toxin can penetrate mucosal surfaces, it cannot penetrate intact skin. If a release were recognized or announced, and authorities anticipated potential airborne exposure, people could protect themselves by covering their mouths and noses with clothing, such as underwear, shirts, scarfs, or handkerchiefs. In addition, after exposure, washing with soap and water would decontaminate clothing, and a 0.1% hypochlorite bleach solution would be effective on contaminated objects and surfaces (36). 

Heterogeneous reactions on solid particles may also play a role in the removal of sulphur dioxide from the atmosphere. In atmospheric photochemical reactions, such particles may function as nucleation centres. Thus, they act as catalysts and grow in size by accumulating reaction products. The final result would be the production of an aerosol with a composition unlike that of the original particle. Little research has been done on the role that solid particles play in the oxidation of sulphur dioxide under conditions like those found in the atmosphere. Soot particles, which consist of elemental carbon contaminated with polycyclic aromatic hydrocarbons produced in the incomplete combustion of carbonacetous fuels, have been shown to catalyse the oxidation of sulphur dioxide to sulphates. 

Contaminants present as gases in the atmosphere can exchange directly across the air/sea boundary or they may be scavenged by rain and snow. Pollutants present on particles (aerosols) may deposit on the ocean either by direct (dry) deposition or they may also be scavenged by precipitation. The removal of gases and/or particles by rain and snow is termed wet deposition. 

US Department of Health and Human Services, Washington Naumova YY, Eisenreich SJ, Turpin BJ et al (2002) Polycyclic aromatic hydrocarbons in the indoor and outdoor air of three cities in the US. Environ Sci Technol 36 2552-2559 Naumova YY, Offenberg JH, Eisenreich SJ et al (2003) Gas/particle distribution of polycyclic aromatic hydrocarbons in coupled outdoor/indoor atmospheres. Atmos Environ 37 703-719 Offenberg JH, Baker JE (1999) Aerosol size distributions of polycyclic aromatic hydrocarbons in urban and over-water atmospheres. Environ Sci Technol 33 3324-3331 Ohta S, Nakao T, Nishimura H et al (2002) Contamination levels of PBDEs, TBBPA, PCDDs/ DFs, PBDDs/DFs and PXDDs/DFs in the environment of Japan. Organohalogen Compd 57 57-60... 

At an air temperature of 283 K (10 °C), an air pressure of 1,013 hPa and 60% relative humidity the water content is around 5.7 g/m. At 303 K (30 °C) and relative humidity of 100%, the water content rises to 31.4 g/m. The water film that condenses when the temperature drops or on relatively cold surfaces is always saturated with oxygen. Whereas corrosive action in a non-marine atmosphere is mainly determined by moisture content and potential industrial contaminations, the marine atmosphere is characterised by a raised content of salt particles carried on the wind from the sea spray. Since the salt particles deposited on the metal surface, or aerosols containing salt, also contain hygroscopic components, e.g. calcium and magnesium chlorides, liquid films form on the surface with very high salt content levels, even if the air is still above the dewpoint. 

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