Total airborne particles

Total airborne particles All the particles surrounded by air in a given volume of air. 

These are an itnprovised version of a totally enclosed motor to protect its live parts from ingress of water, rain, snow or airborne particles etc. This is achieved by providing them with additional protection such as labyrinths at joints such as bearing end covers, centrifugal discs, end shields and terminal box and giving the outer... 

Gram-negative Bacteria. The significant data are summarized in Table IV. Cinkotai et al. (11,12) showed that the prevalence of byssinotic symptoms correlated best with gram-negative rod counts in the total airborne dust from cardrooms of cotton mills. This correlation could be Increased by multiplying the bacterial counts by the years of exposure of the worker. These bacteria also correlated with the number of 2-4 ym particles and the amount of protease in the air. 

Golden, C., and E. Sawkki. Ultrasonic extraction of total particulate aromatic hydrocarbons (TpAH) from airborne particles at room temperature. Int. J. Environ. Anal. Cliem. 4 9-23, 1975. 

There has been great interest in airborne particulate matter recently due to the results of a number of epidemiological studies showing a correlation between increased mortality and levels of airborne particles. Figure 2.14 shows one such correlation reported by Dockery et al. (1993). A clear relationship between mortality rates and the concentration of fine particles PM25, as well as with particle sulfate, is seen. Since sulfate is found primarily in fine particles, these observations are not independent. Schwartz et al. (1996) report a 1.5% increase in total daily mortality with an increase of 10 pg m-3 in PM25. Deaths due to chronic obstructive pulmonary disease increased by 3.3% and those to ischemic heart disease by 2.1%. 

Calculate the mole fractions of SO j, HSO, and SO3- in solution at a pH of 8.0, equal to that of seawater and therefore expected for airborne particles formed from seawater in clean regions as well as the total concentration of S(IV) in solution for 20 ppb S02 in the gas phase. Comment on the implications for the potential role of sea salt particles in the oxidation of S02 in the marine boundary layer. 

FIGURE 9.35 Observed size distributions of total suspended particles and some of the inorganic constituents of airborne particles at Chichi, Ogasawara Islands, Japan, in 1983 (adapted from Yoshizumi and Asakuno, 1986). 

Concurrently, Gordon and co-workers (1973) reported another important phenomenon benzene extracts of airborne particles collected in the Los Angeles Air Basin had 100-1000 times the cell transformation activity of that which could be attributed to the measured levels of known PAHs in the samples. Strikingly, the polar (methanol) fraction of these extracts, which amounted to only 3% of the total mass in the sample of ambient particles, had an activity equal to the neutral benzene extract that contained the remaining 97% of the PAHs (including BaP). 

Humidifiers can be a significant source of airborne particles if tap water is used because as the water evaporates from the aerosol, the solids that were in water are left as particles. For example, Highsmith et al. (1988, 1992) showed that the airborne particle concentration increased linearly with the total dissolved... 

Makkonen U, Hellen H, Anttila P, Ferm M (2010) Size distribution and chemical composition of airborne particles in south-eastern Finland during different seasons and wildfire episodes in 2006. Sci Total Environ 408 644—651... 

Table 3.2 shows measurements of particulate and gaseous stable iodine in the atmosphere. Moyers et al. (1971) used membrane filters and activated charcoal to collect the particulate and gaseous fractions in air at Boston, and found the ratio Ip/Ig to be correlated with the concentration of particulate lead in the air. It was not inferred that Ip was combined with particles of lead, but rather that the concentrations of lead served as an index of the total airborne particulate. Moyers et al. expressed their results as... 

Golden and Sawicki [17] studied ultrasonic extraction of almost all of the polar compounds from airborne particulate material collected on Hi-Vol filters. Full recovery of PAH and good reproducibility were achieved. Total analysis time was approximately 1.5 hours. The same research group also reported a sonication procedure for the extraction of total particulate aromatic hydrocarbon (TpAH) from airborne particles collected on glass fiber filters [18]. Significantly higher recovery of TpAH and PAH were achieved by 40 minutes of sonication than by 6 to 8 hours of Soxhlet extraction. 

C. McLeod, R. Ma, S. Caroli, A. Alimonti, F. Petrucci, B. Bocca, P. Schramel, M. Zischka, C. Pettersson, U. Wass, Levels and risk assessment for humans and ecosystems of platinum group elements in the airborne particles of some European cities, Sci. Total Environ., 299 (2002), ID 19. 

In addition to the need to monitor known problematic compounds, newer compounds are being identified as potential threats to humans and as such need to be monitored in the atmosphere. For example, researchers reported (10) that several chemical and instrumental analyses of HPLC fractions provided evidence for the presence of /V-nitroso compounds in extracts of airborne particles in New York City. The levels of these compounds were found to be approximately equivalent to the total concentrations of polycyclic aromatic hydrocarbons in the air. Since 90% of the N-nitroso compounds that have been tested are carcinogens (10), the newly discovered but untested materials may represent a significant environmental hazard. The procedure involved collecting samples of breathable, particulate matter from the air in New York City. -These samples were extracted with dichloro-methane. Potential interferences were-removed by sequential extractions with 0.2 N NaOH (removal of acids, phenols, nitrates, and nitrites) and 0.2 N H2S04 (removal of amines and bases). The samples were then subjected to a fractional distillation and other treatments. Readers interested in the total details should consult the original article (10). Both thin-layer chromatography (TLC) and HPLC were used to separate the compounds present in the methanolic extract. 

The method by Wells and Alexander uses lower air velocities (the extraction rate is only 50 litres/minute) and does not, therefore, require a deflector plate. The method does not necessarily release all of the potentially airborne particles in the sample in fact, the dust release may be constant in many repeated pourings of the same sample. Either total airborne dust samples may be collected on a filter (i.e. all particles that are still airborne on leaving the box, i.e. smaller than about 10 microns) or only the respirable fraction may be collected by extraction through the Hexhlet sampler. 

Inhalation is actually a less Important route of entry than assumed by CDC, if other data are considered. For example, the EPA has estimated that the average concentration of total suspended particulates (TSP) In Missouri Is about one-half the level assumed by CDC, or about 0.070 mg/m (32.33). Secondly, only a fraction (about 30%) of the total amount of airborne dust Is respirable (less than 10 pm aerodynamic diameter) (32). The percentage of TSP which Is respirable has been estimated by EPA to be no more than 50% (2). Also, the assumption that all of the airborne particles are derived from dioxin-contaminated soil Is overly conservative. Actually, about 50% of the Inhaleable particles are respirable and the remainder are between 10 and 50 pm. Further, about 83% of the non-respirable particles are from crustal material (e.g., soil) and only 47% of the respirable particles are from soil (32). Larger studies conducted by the U.S. EPA have suggested that the portion of Inhaleable dust due to soil can often be much less (34). 

In a study of residential exposure to Cr-laden wastes in Hudson County, New Jersey, Lioy etal., 1992) collected 3-day and 4-day composite samples using low-volume air samplers equipped with 37-mm Teflon filters. Total Cr in airborne particles was determined using XRF with a detection limit of 2 pg g (shown in Table 11.3), and extractable Cr (not shown) was determined using nitric acid/sulfiiric acid digestion and ICP-AES. The mean ratio of extractable Cr to total Cr was 0.3. 

Kent MS, Robbins TG and Made AK (2001) Is total mass of alveolar-deposited airborne particles of beryllium a better predictor of the prevalence of disease A preliminary study of a beryllium processing facility. Appl Occup Environ Hyg 16 539-558. 

To estimate the total exposure to a given chemical in an indoor environment, its distribution between the gas phase, airborne particles and settled dust compartments must be investigated. If partitioning/sorption is the dominant mechanism of association, then there should be a predictable relationship between the particle concentration of a given organic compound and its dust concentration. The contribution of each of these compartments to indoor phthalate exposure has been estimated by Weschler et aL (2008). 

Generally, the sensitivity of X-ray spectrometrie methods is not suffieient for direct measurement of PGE in environmental samples. However, adequate total reflection X-ray fluorescence (TXRF) methods have been developed to enable, after adequate sample preparation and analyte enrichment via Hg-coprecipitation, PGE-determination in various samples like road dust, airborne particles or liver and kidney tissue of exposed European eels (Anguilla anguilla) (Messerschmidt et al. 2000 Sures et al. 2001). 

Seaton A, Cherrie J, Dennekamp M, Donaldson K, Hurley JF, Tran CL (2005) The London underground dust and hazards to health. Occup Environ Med 62 355-362 Sitzmann B, Kendal M, Williams I (1999) Characterisation of airborne particles in London by computer-controlled scanning electron microscopy. Sci Total Environ 241 63-73 Vekemans B, Janssens K, Vincze L, Adams F, Van Espen P (1994) Analysis of X-ray spectra by iterative least squares (AXIL) new developments. X-Ray Spectrom 23 278-285 Zimmer AT, Biswas P (2001) Characterization of the aerosols resulting from arc welding processes. J Aerosol Sci 32 993-1008... 

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