Impact of Botanical and Electrostatic Mechanical Air Purifiers on Office Indoor Air Quality, Occupants Productivity and Satisfaction in Qatar: A Cost-Benefit Analysis

Abstract

Indoor air quality (IAQ) is considered one of the most important indoor environmental quality factors, since air pollution was found to be partially attributed to one in eight deaths globally. For existing buildings, since it is usually impractical to replace or upgrade the existing HVAC system, introducing air purifiers is often the most practical solution. Accordingly, the objective of my research is to evaluate the feasibility and the impact of different air purifiers on improving productivity, satisfaction and health complaints of occupants in Qatar. Four hypotheses were tested: (1) The electrostatic mechanical (EM) purifiers are five times more effective in PM2.5 removal than botanical purifiers, and the same in VOC removal, (2) the botanical purifiers have higher positive impact on satisfaction and self- reported productivity due to their biophilic effect, (3) the EM purifiers have higher positive impact on health complaints reduction, and (3) the ROI is two times higher for the botanical purifiers as a result of their additional biophilic effect and lower cost. A field study was conducted in six office spaces, three as treatment groups and three as control groups, using EM, plants and a fake purifier as a placebo. During the study, PM2.5, VOC and CO2 were monitored as air pollutants. As response variables, changes in self-reported productivity, satisfaction and health symptoms were captured by a weekly occupant survey. Results were analyzed using linear regression and one-way analysis of variances (ANOVA), where detected significant changes were reflected into a developed Cost-Benefit Analysis model. Results have shown that EM air purifier was the most effective in air purifying, while plants were found to have the highest ROI.