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Investigating Indoor Air Problems: How to Find Out What Went Wrong
Published in H.E. Burroughs, Shirley J. Hansen, Managing Indoor Air Quality, 2020
H.E. Burroughs, Shirley J. Hansen
Particle count data can be more helpful in diagnosing indoor air because it enables a more precise analysis and comparison of particle size. This can be helpful in tracking sources as well as determining specific mitigation tactics, such as appropriate filter selection. The use of particle counters also enables the field evaluation of the efficiency performance of installed filtration systems. These data are developed using an instrument that discreetly sizes and counts individual particles carried in the air stream over a size range from .3 microns to 10 microns. The better units have multiple size channels and are equipped with memory capability enabling down loading and data manipulation. A more recent technology enables the recognition of superfine (meaning sub-micron sized) particles and is embodied in a hand held instrument similar to a Geiger counter that will trace sources of ultrafine particles. The tracking of ultrafine particles can help understand contaminant pathways and infiltration, since outdoor air is a primary source of ultrafine particles. It also can assist in the on site tracking of fungal activity in concealed sources of mold spores, if the fungal spores are the primary source of the fine particles. Note the following discussion regarding microbial growth for further information on fungal determination.
Detoxification of Biomedical Waste
Published in Ram Chandra, R.C. Sobti, Microbes for Sustainable Development and Bioremediation, 2019
Bamidele Tolulope Odumosu, Tajudeen Akanji Bamidele, Olumuyiwa Samuel Alabi, Olanike Maria Buraimoh
The installation of certain devices to the incinerator in order to reduce the emission of these toxic gaseous substances could be effective in preventing the contamination of the atmosphere, but this will usually result in an increase of these pollutants in the solid waste phase, as the gaseous phase will be transformed to the solid phase. Furthermore, the high cost of installation of such devices and the level of efficiency of filters in capturing fine particles pose serious disadvantages to the use of incinerator. Ultrafine particles with a size below 1 µm are hardly captured by the filter. The ultrafine particles are usually highly reactive and could cause a serious health effect on humans and animals when inhaled. Hence the development of a nonincinerator method of disposing BMWs is of high advantage and safer compared with the incineration method.
Chemical vapour deposition of ultrafine particles
Published in Kwang Leong Choy, Chemical Vapour Deposition (CVD), 2019
Particles are materials with diameters from nanometres to micrometres. Nanoscale refers to dimensions between 1 and 100 nm, while microscale typically implies dimensions between 100 nm and 100 µm. In this chapter, ‘ultrafine particles’ describe nanoparticles and submicron-sized particles. Ultrafine particles have been used since the early days of human civilisation; therefore, there is substantial knowledge and long history. Back in 1500 BC, the Chinese used carbon black from combustion processes for painting applications, while carbon black is now used in fabricating car tires. The most impressive uses of nanoscaled objects in history is the Lycurgus Cup, which dates back to Roman times (fourth century AD). The extraordinary cup benefits from the dichroic glass which contains colloidal gold and silver nanoparticles that give the spectacular optical properties; it shows red when lit from behind and green when lit from the front [1]. In 1857, Faraday was the first investigator to report the existence of metallic nanoparticles in solutions [2], while Mie provided a quantitative explanation of their colour back in 1908 [3].
Comprehensive characterization of firing byproducts generated from small arms firing of lead-free frangible ammunition
Published in Journal of Occupational and Environmental Hygiene, 2022
Ryan McNeilly, Jacob Kirsh, John Hatch, Ariel Parker, Jerimiah Jackson, Steven Fisher, John Kelly, Christin Duran
When particulates in small arms firing emissions were investigated further using direct reading methods, they were found to be primarily in the ultrafine size range based on number density (Wingfors et al. 2014; Aurell et al. 2019). Wingfors et al. (2014) found that when firing three consecutive rounds of LFF ammunition using a rifle, the concentration of ultrafine particles exceeded 10 × 1010 particles/cm3 immediately after firing, with greater than 90% of these particles smaller than 260 nm (Wingfors et al. 2014). Ultrafine particles are known to deposit efficiently in the gas exchange region of the lung and translocate into the blood stream, which can cause additional systemic health problems including cardiac and neurological diseases (Li et al. 2016; Stone et al. 2017). Due to the small size of the particles, they do not contribute significantly to mass. Since the occupational exposure limit values published by the American Conference of Government Industrial Hygienists (ACGIH®) and the OSHA are on a mass-basis, this highlights the importance of the size fraction of aerosols in firing emissions and requirement to understand characteristics and relevance to health.
Measurement of transient nanoparticle emissions of pulse-jet cleaned filters applying an engine exhaust particle sizer
Published in Aerosol Science and Technology, 2022
Peter Bächler, Jörg Meyer, Achim Dittler
Air pollution can have severe impacts on human health. Exposure to increased particulate matter concentrations can cause, e.g., cardiovascular diseases (German National Academy of Sciences Leopoldina 2019). Particulate matter concentrations are classified regarding their ability to penetrate the human body and potentially cause harm (e.g., PM2.5 is the fraction of particles that may reach the lung, the PM1 fraction may penetrate deeper into the alveoli). Ultrafine particles are especially dangerous due their ability to enter the blood stream and reach the brain. Industrial facilities are among the highest emitters of particulate matter (Federal Environment Agency (Umweltbundesamt) 2009), however the emission of ultrafine particles is in many cases not monitored, as there is no need from a legislative point of view and measurement equipment is expensive (TA Luft, Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit 2002). Nonetheless, regarding health aspects, the nanoparticle emission of industrial facilities is of great interest.
High resolution STEM/EDX spectral imaging to resolve metal distributions within ∼100 nm combustion generated ash particles
Published in Aerosol Science and Technology, 2019
Yueming Wang, Brian Van Devener, Xiaolong Li, Jost O. L. Wendt
Particles with diameter smaller than 100 nm are referred as ultrafine particles in this article. During the combustion process, a few percent of inorganic minerals can be vaporized and converted into inorganic vapors. Volatile elements such as Na, K, Cl, P, and S are more readily vaporized than refractory elements, but a small portion of refractory metal oxide ash (SiO2, CaO, and MgO) can be reduced by CO during char oxidation process to form volatile inorganic vapors (SiO, Ca, and Mg) (Quann and Sarofim 1982). After being released from the char particles, these inorganic vapors nucleate to form nano-sized nuclei, which can further grow in size through coagulation and generate ultrafine particles (Xu et al. 2011). These processes are greatly affected by the fuel properties and combustion conditions (Liu, Wang, and Wendt 2017). Due to the small size and high surface area, ultrafine particles have a greater tendency to absorb hazardous elements that are transferred from coal ash to vapor phase during combustion process (Saikia et al. 2015).