Urban atmosphere workers

Indeed, based on the number, surface, and volume distributions shown in Fig. 9.6, Whitby and co-workers suggested that there were three distinct groups of particles contributing to this atmospheric aerosol. Particles with diameters >2.5 yu,m are identified as coarse particles and those with diameters 2.5 pm are called fine particles. The fine particle mode typically includes most of the total number of particles and a large fraction of the mass, for example, about one-third of the mass in nonurban areas and about one-half in urban areas. The fine particle mode can be further broken down into particles with diameters between 0.08 and 1-2 yxm, known as the accumulation range, and those with diam-... 

The possibility of such organic films being formed on aerosol particles in the atmosphere as well as on fog, cloud, and rain droplets and snowflakes has been discussed in detail by Gill and co-workers (1983). As seen from our earlier discussions on the types of organics that have been observed in both urban and nonurban aerosols, there is no question that surface-active species... 

Additionally, in two different monitoring campaigns conducted in the center of Milan, Italy, Ciccioli and co-workers (1993) reported 2-nitrofluoranthene, 2-nitropyrene, and 1-nitropyrene were the only ni-troarenes detected. Subsequently, in a comprehensive study of the atmospheric formation and transport of 2-nitrofluoranthene and 2-nitropyrene, they established their presence and levels in ambient particles collected at sites located in urban, suburban, forest, and remote areas in Europe, Asia, America, and Antarctica (Ciccioli et al., 1996, and references therein see also Ciccioli et al., 1995). 

Workers often do not realize that such elaborate precautions against atmospheric contamination may be necessary since such effects could appear simply as high and variable blank levels. As part of the Project, atmospheric lead contamination was studied in a typical industrialized urban laboratory. Clean 15-ml polyethylene beakers each containing... 

In the past decade or so, extensive work by Diamond and co-workers [312-317] has shown that exposed outdoor surfaces in urban areas rapidly become coated with a complex mixture of chemical compounds ( urban sxuface film ), most readily encountered as window grime. This film grows via accretion from the atmosphere and is removed by rain wash-off, or revolatilization processes, yielding an (estimated) steady-state thickness of several tens to hundreds of nanometers. Chemical analysis of these films has been carried out both in a broad brush approach [312, 313], which identified the compound classes present, and by more detailed studies [315-317] that determined the specific compounds within these classes. 

The danger of unintentional inhalation of nanostmctures is not limited to workers and researchers specifically involved in nanotechnology-related fields. In fact, there are a surprisingly large number of nanoparticles in our ambient atmosphere, reaching as high as 10 -10 nanoparticles/L of air in both urban... 

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