KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Ingviya, ThammasinHas files: No

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Ventilation improvement for effective protection of healthcare workers in negative pressure airborne infectious isolation room from viral aerosols
    (2024-07-01)
    Kaeophet, Thanchanok
    ;
    Dejchanchaiwong, Racha
    ;
    Tekasakul, Perapong
    ;
    Phonsahwat, Thongchai
    ;
    Khongprom, Parinya
    A negative pressure airborne infectious isolation room (AIIR) is the primary healthcare air contamination control system used for the treatment of severe respiratory infectious patients. Effects of the ventilation system configuration and conditions on airflow pattern, aerosol distribution and ventilation performance were investigated using computational fluid dynamics (CFD). The field measurement by SARS-CoV-2 environmental surface test was also conducted. The cycle threshold values from transcription polymerase chain reaction (RT-PCR) method showed inverse relation to the simulated number of particles trapped on the surfaces indicating a good agreement. Modification of the present AIIR to have alignment between air inlet and outlet where the aspect ratio of the air outlet, Width (W): Height (H) = 1:1 (Improved case: IC#1) showed a 78 % reduction of aerosol concentration in healthcare workers (HCWs) zones. Aerosol concentrations were increased when the openings of the air outlet were enlarged. Addition of air outlet led to large swirling air, resulting in more aerosols being trapped and suspended in the air. Results suggested that AIIR with alignment air inlet on the ceiling and air outlet at the wall over the patient's head with W:H = 1:1 be the most suitable configuration to maximize the ventilation performance and minimize exposure risk to aerosolized viral infection for HCWs. Air change rate plays a more important role than the differential pressure on the removal efficiency. The differential pressure value should be at least −2.5 Pa and the air supply rate 12 ACH for effective protection of HCWs in the negative pressure AIIR.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Source apportionment of PM2.5 in Thailand’s deep south by principal component analysis and impact of transboundary haze
    (2023-08-01)
    Chaisongkaew, Phatsarakorn
    ;
    Dejchanchaiwong, Racha
    ;
    Inerb, Muanfun
    ;
    Mahasakpan, Napawan
    ;
    Nim, Nobchonnee
    Atmospheric particulate matter smaller than 2.5 micron (PM<inf>2.5</inf>) was evaluated at four sites in the lower southern part of Thailand during 2019–2020 to understand the impact of PM<inf>2.5</inf> transport from peatland fires in Indonesia on air quality during the southwest monsoon season. Mass concentration and chemical bound-PM, including carbon composition, e.g., organic carbon (OC) and elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs), and inorganic elements, were analyzed. The PM<inf>2.5</inf> emission sources were identified by principal components analysis (PCA). The average mass concentrations of PM<inf>2.5</inf> in the normal period, which represents clean background air, from four sites was 3.5–5.1 µg/m<sup>3</sup>, whereas during the haze period, it rose to 5.4–13.5 µg/m<sup>3</sup>. During the haze period, both OC and EC were 3.5 times as high as in the normal period. The average total PAHs and BaP-TEQ of PM<inf>2.5</inf> during the haze period were ~ 1.3–1.7 and ~ 1.2–1.9 times higher than those in the normal period. The K concentrations significantly increased during haze periods. SO<inf>4</inf><sup>2−</sup> dominated throughout the year. The effects of external sources, especially the transboundary haze from peatland fires, were significantly enhanced, because the background air in the study locations was generally clean. PCA indicated that vehicle emission, local biomass burning, and secondary particles played a key role during normal period, whereas open biomass burning dominated during the haze phenomena. This was consistent with the OC/EC and PAH diagnostic ratios. Backward trajectories confirmed that the sources of PM during the haze period were predominantly peatland fires in Sumatra, Indonesia, due to southwest wind.