The effects of manual airing strategies and architectural factors on the indoor air quality in college classrooms: a case study

Abstract

In China, natural ventilation is a common way of improving indoor air quality (IAQ) in college classrooms. However, until now, the effects of both manual airing strategies and architectural factors on IAQ in classrooms have not been well explored. The present work aimed to investigate the effect of manual airing strategies, such as opening doors and opening exterior or interior windows, on the concentrations of both carbon dioxide (CO2) and fine particulate matter (PM2.5) in classrooms using field measurements.Through simulation, the effects of floor level, room orientation and the height of interior windows on CO2 concentration were also analysed. The results of this study revealed that 1) simultaneously opening doors and exterior windows or opening the doors alone could effectively reduce the indoor CO2 concentration, but the same effect could not be achieved by opening interior windows only; 2) the indoor PM2.5 concentration was primarily affected by the level of outdoor PM2.5, and it may exceed the recommended limit by 33% when the outdoor pollution level is high, even with closed doors and windows; and 3) in winter, both floor level and classroom orientation exerted a significant influence on the indoor CO2 concentration, but the height of interior windows had no effect.

Field and intervention study on indoor environment in professional classrooms

“…The architectural design courses are taught in this form in universities in China. The architectural design is the main course for architecture major, consisting of architectural design (1) to (8), with one architectural design course per semester.…”

“…The deterioration of indoor air quality is caused by a combination of outdoor pollutants entering classrooms and indoor sources of pollutants [7,8]. In the research field of indoor environments, indoor CO2 concentration, content, and concentration of volatile organic compounds (VOCs) can be regarded as a measure of indoor air quality affected by human pollutants [9].…”

Fine dust inflow paths and heating load variation based on field measurement of air tightness in two Korean schools

“…In addition, high concentrations of outdoor fine dust and CO 2 led to the indoor concentrations exceeding the threshold by 33%, even when the doors were closed. The floor level and direction in the building were also found to have an effect on the indoor CO 2 level [ 7 ]. Similarly, in a study conducted on four elementary schools in China, in which the indoor air quality was estimated and the influencing factors were analyzed, the airtightness of the building and resident activities were found to have a strong effect on the indoor air quality; one building with a high airtightness showed a relatively low level of PM2.5 [ 8 ].…”

Exploring the impact of opening ratio on indoor thermal environment: A study on natural ventilation design

“…7 The European Norm (EN) also includes a formula for calculating the center value of comfortable temperature using the average outdoor temperature derived from office buildings with natural ventilation as a variable. 8 Regarding improvements in Indoor Air Quality (IAQ), Yu et al 9 conducted field measurements and simulations of a four-story school in China and found that the maximum CO 2 concentration on the first floor was 21.1% lower than that on the fourth floor. Furthermore, the processing time required for customer conversations in call centers was shorter with an increased ventilation rate, which lead to improved work performance (i.e., speed of work).…”