Urban air particles

Ramdahl, T., Becher, G., and Bjorseth, A. Nitrated polycyclic aromatic hydrocarbons in urban air particles. Environ. Sci. Technol, 16(12) 861-865, 1982. 

Ramdahl, T., G. Becher, and A. Bjprseth, Nitrated Polycyclic Aromatic Hydrocarbons in Urban Air Particles, Environ. Sci. Technol., 16, 861-865 (1982b). 

Pankow (1994a,b) proposed that gaseous POPs also absorb into a liquid-like organic film on the particles. Liang and Pankow (1996), and Pankow (1999) found the sorptive capacity of environmental tobacco smoke (almost entirely organic matter) and urban air particles (about 20% organic matter) for n-alkanes and PAHs was nearly the same when normalized to the organic content of the particles. Gas absorption is expressed by ... 

In four urban investigations, PAHs were associated with urban air particles to a greater extent than OCs of the same vapor pressure (Bidleman et al., 1986 Cotham and Bidleman, 1995 Ngabe and Bidleman, 1992 Harner and Bidleman, 1998a), but another study in Denver, Colorado found about the same particle / gas distributions for alkanes, PAHs, PCBs,... 

The oxygen burst of monocytes induced by ambient air particles (with the exception of oil fly ash particles) was less than the response elicited by polymorphonuclear leucocytes (Prahalad etal. 1999). The luminol-enhanced chemiluminescence response of polymorphonuclear leucocytes separated from heparinised human blood was generally increased with all washed particles, with oil fly ash and one urban air particle showing statistically significant (P <0.05) differences between dHjO-washed and unwashed particles. The luminol-enhanced chemiluminescence activity in polymorphonuclear leucocytes induced in post particles... 

A. Epidemiology Studies Suggest an Association Between Urban Air Particles and Increased Mortality... 

D. Components of Urban Air Particles Responsible for Increased Lung Injury... 

Dong W, Lewtas J, Luster MI. Role of endotoxin in tumor necrosis factor alpha expression from alveolar macrophages treated with urban air particles. Exp Lung... 

When a liquid or solid substance is emitted to the air as particulate matter, its properties and effects may be changed. As a substance is broken up into smaller and smaller particles, more of its surface area is exposed to the air. Under these circumstances, the substance, whatever its chemical composition, tends to combine physically or chemically with other particles or gases in the atmosphere. The resulting combinations are frequently unpredictable. Very small aerosol particles (from 0.001 to 0.1 Im) can act as condensation nuclei to facilitate the condensation of water vapor, thus promoting the formation of fog and ground mist. Particles less than 2 or 3 [Lm in size (about half by weight of the particles suspended in urban air) can penetrate the mucous membrane and attract and convey harmful chemicals such as sulfur dioxide. In order to address the special concerns related to the effects of very fine, iuhalable particulates, EPA replaced its ambient air standards for total suspended particulates (TSP) with standards for particlute matter less than 10 [Lm in size (PM, ). 

One example of normal-phase liquid chromatography coupled to gas chromatography is the determination of alkylated, oxygenated and nitrated polycyclic aromatic compounds (PACs) in urban air particulate extracts (97). Since such extracts are very complex, LC-GC is the best possible separation technique. A quartz microfibre filter retains the particulate material and supercritical fluid extraction (SPE) with CO2 and a toluene modifier extracts the organic components from the dust particles. The final extract is then dissolved in -hexane and analysed by NPLC. The transfer at 100 p.1 min of different fractions to the GC system by an on-column interface enabled many PACs to be detected by an ion-trap detector. A flame ionization detector (PID) and a 350 p.1 loop interface was used to quantify the identified compounds. The experimental conditions employed are shown in Table 13.2. 

An average adult breathes about 8.50 X 103 L of air per day. The concentration of lead in highly polluted urban air is 7.0 X 10 6 g of lead per one m3 of air. Assume that 75% of die lead is present as particles less than 1.0 X 10 6 m in diameter, and that 50% of die particles below that size are retained in the lungs. Calculate the mass of lead absorbed in this manner in 1 year by an average adult living in this environment... 

Cronn DR, Charlson RJ, Knights RL, et al. 1977. A survey of the molecular nature of primary and secondary components of particles in urban air by high-resolution mass spectrometry. Atmos Environ 11 929-937. 

Urban aerosols are complicated systems composed of material from many different sources. Achieving cost-effective air particle reductions in airsheds not meeting national ambient air quality standards requires identification of major aerosol sources and quantitative determination of their contribution to particle concentrations. Quantitative source Impact assesment, however, requires either calculation of a source s impact from fundamental meteorological principles using source oriented dispersion models, or resolving source contributions with receptor models based on the measurement of characteristic chemical and physical aerosol features. Q)... 

Particulate carbon in the atmosphere exists predominantly in three forms elemental carbon (soot) with attached hydrocarbons organic compounds and carbonates. Carbonaceous urban fine particles are composed mainly of elemental and organic carbon. These particles can be emitted into the air directly in the particulate state or condense rapidly after Introduction into the atmosphere from an emission source (primary aerosol). Alternatively, they can be formed in the atmosphere by chemical reactions involving gaseous pollutant precursors (secondary aerosol). The rates of formation of secondary carbonaceous aerosol and the details of the formation mechanisms are not well understood. However, an even more fundamental controversy exists regarding... 

TABLE 9.18 Some Difunctionally Substituted Alkane Derivatives Found in Submicron Ambient Particles in Urban Air ... 

Cronn, D. R., R. J. Charlson, R. L. Knights, A. L. Crittenden, and B. R. Appel, A Survey of the Molecular Nature of Primary and Secondary Components of Particles in Urban Air by High Resolution Mass Spectrometry, Atmos. Environ., 11, 929-937 (1977). 

Harner, T., and T. F. Bidleman, Octanol-Air Partition Coefficient for Describing Particle Gas Partitioning of Aromatic Compounds in Urban Air, Environ. Sci. Technol., 32, 1494-1502 (1998). 

Throughout this chapter, we cite examples of the use of the NIST Standard Reference Material SRM 1649, which is referred to as Air Particles or Urban Air Particulate Matter, (a) to validate analytical procedures for determination of PAHs and PACs in samples of complex mixtures of particulate matter in ambient air and (b) for laboratory intercomparisons of methodologies for bacterial bioassays and bioassay-directed fractionations of organic extracts of such mixtures (e.g., see Claxton et al., 1992a Lewtas et al., 1990a, 1992 and May et al., 1992). 

In one of the first studies of the vapor-phase mutagenicity of polluted urban air, Alfheim and co-workers (1985) collected both ambient particles and vapor-phase compounds and used the Salmonella typhlmurium reversion assay. The direct activities ( —S9) of the extracts generally exceeded the promutagenicities (+ S9), and furthermore, the vapor-phase mutagenicity ranged from 0 to 88% of the total activity. 

Figure 10.25 shows these mutagrams for the vapor and particle phases, respectively. Interestingly, the total direct mutagenicity of the vapor phase, 210 rev m-3, was actually greater than that of the particle phase, 160 rev m 3 furthermore, its mutagenicity profile was substantially different. Thus, fraction 4 is the major peak for the vapor-phase sample whereas most of the particle-phase mutagenicity is in the more polar peaks 6 and 7. Similar enhancements in the contributions of more polar species were reported for bioassay-directed fractionation of SRM 1649 urban air particulate matter (Schuetzle and Lewtas, 1986 Nishioka et al., 1988 ... 

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