Effects of ultraviolet germicidal irradiation and swirling motion on airborneStaphylococcus aureus,Pseudomonas aeruginosaandLegionella pneumophilaunder various relative humidities

Chang, Ching‐Wen; Li, S.-Y.; Huang, Sheng-Hsiu; Huang, Chen-Kang; Chen, Y.-Y.; Chen, C.-C.

doi:10.1111/j.1600-0668.2012.00793.x

Cited by 32 publications

(28 citation statements)

References 29 publications

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“…2b and S4c). The accumulation of Pseudomonas in the smallest size fraction is in line with the small aerodynamic size (< 1 µm) of common Pseudomonas species (Chang et al, 2013;Möh-ler et al, 2008;Pietsch et al, 2015). Overall, the relative amount of Pseudomonas from all bacteria was highest in the size fraction 1-2.5 µm (Fig.…”

Section: Seasonal Variation and Size Distribution Of Microorganismsmentioning

confidence: 52%

Characterization of free amino acids, bacteria and fungi in size-segregated atmospheric aerosols in boreal forest: seasonal patterns, abundances and size distributions

et al. 2017

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Abstract. Primary biological aerosol particles (PBAPs) are ubiquitous in the atmosphere and constitute ∼ 30 % of atmospheric aerosol particle mass in sizes > 1 µm. PBAP components, such as bacteria, fungi and pollen, may affect the climate by acting as cloud-active particles, thus having an effect on cloud and precipitation formation processes. In this study, size-segregated aerosol samples (< 1.0, 1-2.5, 2.5-10 and > 10 µm) were collected in boreal forest (Hyytiälä, Finland) during a 9-month period covering all seasons and analysed for free amino acids (FAAs), DNA concentration and microorganism (bacteria, Pseudomonas and fungi). Measurements were performed using tandem mass spectrometry, spectrophotometry and qPCR, respectively. Meteorological parameters and statistical analysis were used to study their atmospheric implication for results. Distinct annual patterns of PBAP components were observed, late spring and autumn being seasons of dominant occurrence. Elevated abundances of FAAs and bacteria were observed during the local pollen season, whereas fungi were observed at the highest level during autumn. Meteorological parameters such as air and soil temperature, radiation and rainfall were observed to possess a close relationship with PBAP abundances on an annual scale.

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Section: Seasonal Variation and Size Distribution Of Microorganismsmentioning

confidence: 52%

Characterization of free amino acids, bacteria and fungi in size-segregated atmospheric aerosols in boreal forest: seasonal patterns, abundances and size distributions

et al. 2017

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“…Lin and Li reported that a 2-log reduction of nebulized E. coli was achieved by conventional UV lamp (UVGI system) irradiation at 2.4 mJ/cm 2 at 80% RH (26). Also, aerosols of S. aureus were reduced by 3 logs at a dosage of 2,300 mJ/cm 2 with a UVGI system, 30-liter/min airflow, and 87.3 to 90% RH (27). These bacteria are associated with foodborne illness; our results provide a significant baseline of data to help ensure biological food safety in processing.…”

Section: Resultsmentioning

confidence: 99%

UVC LED Irradiation Effectively Inactivates Aerosolized Viruses, Bacteria, and Fungi in a Chamber-Type Air Disinfection System

Kim

Kang

2018

Appl Environ Microbiol

155

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In this study, the possibility of inactivating viral, bacterial, and fungal aerosols in a chamber-type air disinfection system by using a UVC light-emittingdiode (LED) array was investigated and inactivation rate constants of each microorganism were calculated in fitting curves of surviving populations. UVC LED array treatment effectively inactivated viral infectivity, achieving 5-log reductions within 45 mJ/cm 2 for MS2, Q␤, and X174 viruses. UVC LED array effectiveness in inactivating Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Staphylococcus aureus aerosols achieved 2.5-to 4-log reductions within 1.5 to 4.6 mJ/cm 2 . Also, 4-log reductions of Aspergillus flavus and Alternaria japonica were achieved at a dosage of 23 mJ/cm 2 using UVC LED array irradiation. The highest UV susceptibility, represented by the inactivation rate constant, was calculated for bacteria, followed by fungi and viruses. UVC LED, an innovative technology, can effectively inactivate microorganisms regardless of taxonomic classification and can sufficiently substitute for conventional mercury UV lamps. IMPORTANCE The United Nations Environment Programme (UNEP) convened the Minamata Convention on Mercury in 2013 to ban mercury-containing products in order to ensure human and environmental health. It will be effectuated in 2020 to discontinue use of low-pressure mercury lamps and new UV-emitting sources have to replace this conventional technology. However, the UV germicidal irradiation (UVGI) system still uses conventional UV lamps, and no research has been conducted for air disinfection using UVC LEDs. The research reported here investigated the inactivation effect of aerosolized microorganisms, including viruses, bacteria, and fungi, with an UVC LED module. The results can be utilized as a primary database to replace conventional UV lamps with UVC LEDs, a novel type of UV emitter. Implementation of UVC LED technology is truly expected to significantly reduce the extent of global mercury contamination, and this study provides important baseline data to help ensure a healthier environment and increased health for humanity.

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“…190 Another potential engineering control that has shown to be effective for other respiratory pathogens is the incorporation of UV germicidal irradiation (UVGI) into indoor air systems for disinfection. 191, 192 Using UV or photocatalytic treatments for disinfection of airborne Legionella has shown some promise; 193, 194 however, fungi might protect bacteria from these types of treatment. 195 In addition to disinfecting the air, it is also important for cooling systems to be regularly cleaned to inhibit biofilm growth.…”

Section: Introductionmentioning

confidence: 99%

“…UV disinfection of airborne bacteria is not an independent factor, as UV disinfection can be affected by relative humidity. 193, 205 Although relative humidity is likely to be the most important environmental factor affecting Legionella survival, for completeness, temperature and solar radiation also merit attention, as results could lead to various engineering controls to prevent legionellosis outbreaks. Finally, we need a more complete understanding of Legionella survival dynamics within aerosols, although as discussed earlier, we first need to understand if we should focus on VBNC or culturable Legionella .…”

Section: Introductionmentioning

confidence: 99%

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

Prussin

Schwake

Marr

2017

Building and Environment

101

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Legionella is a genus of pathogenic Gram-negative bacteria responsible for a serious disease known as legionellosis, which is transmitted via inhalation of this pathogen in aerosol form. There are two forms of legionellosis: Legionnaires' disease, which causes pneumonia-like symptoms, and Pontiac fever, which causes influenza-like symptoms. Legionella can be aerosolized from various water sources in the built environment including showers, faucets, hot tubs/swimming pools, cooling towers, and fountains. Incidence of the disease is higher in the summertime, possibly because of increased use of cooling towers for air conditioning systems and differences in water chemistry when outdoor temperatures are higher. Although there have been decades of research related to Legionella transmission, many knowledge gaps remain. While conventional wisdom suggests that showering is an important source of exposure in buildings, existing measurements do not provide strong support for this idea. There has been limited research on the potential for Legionella transmission through heating, ventilation, and air conditioning (HVAC) systems. Epidemiological data suggest a large proportion of legionellosis cases go unreported, as most people who are infected do not seek medical attention. Additionally, controlled laboratory studies examining water-to-air transfer and source tracking are still needed. Herein, we discuss ten questions that spotlight current knowledge about Legionella transmission in the built environment, engineering controls that might prevent future disease outbreaks, and future research that is needed to advance understanding of transmission and control of legionellosis.

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Effects of ultraviolet germicidal irradiation and swirling motion on airborneStaphylococcus aureus,Pseudomonas aeruginosaandLegionella pneumophilaunder various relative humidities

Cited by 32 publications

References 29 publications

Characterization of free amino acids, bacteria and fungi in size-segregated atmospheric aerosols in boreal forest: seasonal patterns, abundances and size distributions

Characterization of free amino acids, bacteria and fungi in size-segregated atmospheric aerosols in boreal forest: seasonal patterns, abundances and size distributions

UVC LED Irradiation Effectively Inactivates Aerosolized Viruses, Bacteria, and Fungi in a Chamber-Type Air Disinfection System

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

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