Airborne studies

Hobbs, P.V. and L.F. Radke Airborne Studies of the Smoke from the Kuwait Oil... 

Hobbs, P.V., Radke, L.F. (1992). Airborne studies of the smoke from the Kuwait oil fires. Science 256 987-91. 

Andreae, M. O., T. W. Andreae, H. Annegarn, F, Beer, H. Cachier, W, Elbert, G. W. Harris, W. Maenhaut, I. Salma, R. Swap, F. G. Wienhold, and T. Zenker. 1998. Airborne studies of aerosol emissions from savanna fires in southern Africa 2. Aerosol chemical composition. Journal of Geophysical Research 103 32119-32128. 

Figure 6.13 shows evidence for NOy and H2O removal in the same region displaying enhanced CIO in the Antarctic stratosphere (poleward of about 64°S in that particular transect) from airborne studies. Later measurements documenting the denitrification and dehydration of the Antarctic lower stratosphere include those of Santee et al. (1998, 1999), Voemel et al. (1995), and Pierce et al.( 1994), but see below for a discussion of the roles of denitrification and dehydration in ozone depletion chemistry. 

Radke, L. F., J. L. Stith, D. A. Hegg, and P. V. Hobbs (1978). Airborne studies of particles and gases from forest fires. J. Air Pollut. Control Assoc. 28, 30-34. 

As part of the Megacity Initiative Local and Global Research Observations (MILAGRO) project, a comprehensive airborne study by Yokelson et al. reported the first detailed field measurements of biomass emissions in the Northern Hemisphere tropics [169]. Volatile emissions were measured from 20 deforestation and crop residue fires on the Yucatan peninsula. This included two trace gases which are often considered to be useful as indicators of biomass burning. One we have discussed before, namely acetonitrile, and the other is hydrogen cyanide. A variety of instrumentation was co-deployed for this investigation (FTIR spectroscopy, GD-FID, a GC-Trace Analytical Reduction Gas Detector, fluorescence and chemiluminescence instruments and various other spectrometers). PTR-MS was used to monitor methanol, acetonitrile, acetaldehyde, acetone, methyl ethyl ketone, methyl propanal, hydroxyacetone plus methyl acetate, benzene and 13 other volatile species. 

The relationship between workplace exposure to airborne asbestos fibers and respiratory diseases is one of the most widely studied subjects of modern epidemiology (37—39). Asbestos-related health concerns were first raised at the beginning of the century in the UK and the latter appears to have been the first country to regulate the asbestos-user industry (40). However, at that time, infectious respiratory diseases were a much greater concern than those arising from poor industrial hygiene practices. 

Receptor Models. Receptor models, by their formulation, are effective in determining the contributions of various sources to particulate matter concentrations. In classic studies, sources contributing to airborne particle loadings have been identified in Washington, D.C. (78), St. Louis (9,24), Los Angeles (7,12), Portiand, Oregon (78), and Boston (79—81), as well as other areas including the desert (82). 

Chapter 5 describes simplified methods of estimating airborne pollutant concentration distributions associated with stationary emission sources. There are sophisticated models available to predict and to assist in evaluating the impact of pollutants on the environment and to sensitive receptors such as populated areas. In this chapter we will explore the basic principles behind dispersion models and then apply a simplified model that has been developed by EPA to analyzing air dispersion problems. There are practice and study problems at the end of this chapter. A screening model for air dispersion impact assessments called SCREEN, developed by USEPA is highlighted in this chapter, and the reader is provided with details on how to download the software and apply it. 

Infectious patients present a difficult challenge when trying to protect health care workers. These patients must be isolated from the health care workers as well as from the other patients in the hospital. Special isolation rooms are used for this purpose. These rooms are generally used for isolation of infectious tuberculosis (TB) patients, but could be used for patients with other airborne-transmitted diseases. In the United States, there were 22 812 new cases of tuberculosis in 1993, equal to 8.7 per 100 000 population. This represents a 2.8% increase since 1985, following a 6-7% annual decline from 1981-1984.Several studies have documented higher than expected tuberculin skin test (TST) conversion rates in hospital personnel.The National Institute for Occupational Safety and Health " reports that multiple-drug-resistant (MDR) strains of TB have been reported in 40 states and have caused outbreaks in at least 21 hospitals, with 18-35% of exposed workers having documented TST conversions. 

Industries that burn wood, gas, oil or coal contribute most of the rest of airborne B(a)P. Studies on animals have shown that contact with BaP and PAH can cause skin cancer, but the effects of breathing or ingesting them are not yet well enough studied to draw a conclusion as to other cancers. Animal tests have shown that exposure to BaP may cause reproduction difficulty. The U.S. government considers BaP a human carcinogen. 

Solids containing oxidized anions (carbonates, sulfates, hydroxides, and oxides) are the dominant forms of Cu in airborne particulate matter. In the few studies that have addressed the reactions of these particles in atmospheric washout, about 50% of the copper has been found to be soluble. Since the solubility is strongly dependent on pH, acid precipitation and acidification of receiving waters may have a significant effect on the form and fate of airborne copper. 

J.N. Seiber and J.E. Woodrow, Airborne residues and human exposure, in Determination and Assessment of Pesticide Exposure, ed. M. Siewierski, Studies in Environmental Science 24, Elsevier, New York, pp. 133-146 (1984). 

Vertical surfaces collect spray primarily by impaction. Plants and other entities with a vertical component will collect some material by impaction, and typically also by deposition, as discussed in the previous section. While horizontal collectors will tend to collect all or most material that falls out on to them, vertical collectors will have collection efficiencies that are more closely related to their physical characteristics, especially collector diameter. The SDTF used a-cellulose cards oriented perpendicular to the ground and strings made of cotton or Teflon in its field studies to assess spray volumes at locations above the ground. Many other researchers have used strings for assessing airborne spray volumes in drift studies. ... 

---