Effect of enhanced supply air filtration in buildings on protecting citizens from environmental radioactive particles

Abstract

The effect of enhanced filtration on protection citizens staying indoor against airborne radionuclides released during nuclear core melt accidents was determined by field measurements using outdoor particles as simulants. An electrically enhanced filter was installed in the HVAC system of an office building and its removal efficiency for particles was altered by using a separate particle charging section in power on and off positions. The effect of air filtration on indoor particle concentrations was determined by using an automated measurement system which was continuously sampling from the outdoor air, filtered supply air and exhaust air. With the aid of the measured outdoor and modelled indoor concentrations the indoor/outdoor ratio of particles of outdoor origin could be accurately determined. External charging of the particles increased the electret filters removal efficiency for 0.4 µrn size particles from 60% to 95%, resulting in decrease of the average I/O ratio of the same size particles from 0.67 to 0.40. Despite the high improvement in the supply air filtration efficiency the indoor concentrations decreased only modestly which is likely due to the leaky construction of the building, demonstrating the detrimental effect of air infiltration on the protection provided by buildings against outdoor airborne hazards. Practical implications: The developed method allows quantification of the key parameters affecting the protection of buildings against outdoor contaminants, thus allowing accurate estimation of size resolved indoor to outdoor ratios for fine particles. The electrically enhanced filter can remove effectively also submicron particles thus reducing the occupant exposure to outdoor hazardous or harmful materials. Best results can be achieved with airtight buildings.

Place Attachment and Household Disaster Preparedness: Examining the Mediation Role of Self-Efficacy

“…Some scholars and practitioners differentiate the two concepts. They suggest that mitigation activities are related to the physical and engineering efforts and long-run solutions (e.g., building sea walls) [ 2 , 3 ], while the preparedness activities are more about the knowledge and capacity building activities, but some other researchers treat all the pre-event mitigation and preparedness activities as similar concepts [ 4 , 5 ]. Disaster preparedness behaviors include all the actions taken to reduce the potential impact of potential disasters.…”

Filter evaluation and selection for heating, ventilation, and air conditioning systems during and beyond the COVID ‐19 pandemic

“…3 Filters, such as those rated with a minimum efficiency reporting value (MERV), are commonly used in HVAC systems to capture particles on filtration fibers. [3][4][5][6][7] In addition, electrostatic enhanced air filters (EEAF) can assist particle removal by active ionization. 4,8,9 In January 2021, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommended a MERV of no less than 13 filters for building HVAC systems, 10 to reduce the transmission of indoor infectious airborne viruses in heating, ventilation, and air conditioning (HVAC) systems during the COVID-19 pandemic.…”

“…Filters, such as those rated with a minimum efficiency reporting value (MERV), are commonly used in HVAC systems to capture particles on filtration fibers 3–7 . In addition, electrostatic enhanced air filters (EEAF) can assist particle removal by active ionization 4,8,9 .…”