Comparison of the indoor air quality in an office operating with natural or mechanical ventilation using short-term intensive pollutant monitoring

Abstract

Building ventilation systems are used to mitigate occupant exposure to airborne pollutants such as particulate matter (PM), carbon dioxide and total volatile organic compounds. Building rating systems such as Leadership in Energy and Environmental Design promote the use of natural ventilation to reduce building energy consumption while improving occupant satisfaction. A number of investigations have attempted to compare indoor air quality (IAQ) between spaces with natural or mechanical ventilation without reaching a consensus regarding quantitative impacts. This work provides direct quantitative comparison of the IAQ of a single office space designed for operation with either mechanical or natural ventilation. Natural ventilation has been shown to maintain pollutant accumulation below current standards governing IAQ but is subject to significant airflow variability. In contrast, the mechanical ventilation was shown to result in lower levels of indoor pollution and provide tight control of pollutant levels. The correlation between natural ventilation air exchange rate and concentration of total volatile organic compounds was −0.66 compared to no significant correlation for mechanical ventilation. Average indoor to outdoor PM2.5 ratios were found to be 0.87 and 0.5 for natural and mechanical ventilation, respectively. These results show difficulty in controlling indoor pollutants using prescriptive standard ventilation strategies and that performance-based hybrid ventilation systems provide the most flexibility in meeting IAQ needs.

Indoor particulate pollution in fitness centres with emphasis on ultrafine particles

“…In agreement, for these two FC ambient PM 10 levels were signi ficantly (p < 0.05) higher (median of 23 and 21 mgm À3 at FC3 and FC4; Table 3S) than those indoors, whereas this was not the case for the FC1 eFC2 that were naturally ventilated. Similarly, previous studies reported higher penetration of outdoor PM through open windows indoors under natural ventilation conditions than when using mechanical ventilations (Montgomery et al, 2015;Loupa et al, 2007 ).…”

Assessment of occupant-behavior-based indoor air quality and its impacts on human exposure risk: A case study based on the wildfires in Northern California

“…Behaviours such as window opening and closing (Stabile et al 2017), HVAC operation, and walking into or out of a room (Montgomery et al 2015 Many previous experimental studies focused on the separate impacts of occupant behaviors and building performances on the indoor airflow patterns and pollutant diffusion process, such as human movements, air-conditioning system-related parameters and window operation-related natural ventilation (Luo et al 2016;Luongo et al 2016). Several Computational Fluid Dynamics (CFD) models have also been improved by validating with quantitative measurements (Luo et al 2018b;Gosselin and Chen 2008).…”

Ventilation online monitoring and control system from the perspectives of technology application

“…19 So, to improve indoor air quality and energy efficiency, many investigators have been working on new advanced ventilation technologies. [20][21][22][23] The control of ventilation by mechanical means in HVAC system can have an important impact on IAQ 24 and energy consumption. 24,25 There is a need for new technologies that can control the ventilation system based on requirements and pollution situation in the building.…”