Indoor-outdoor concentrations of particulate matter in nine microenvironments of a mix-use commercial building in megacity Delhi

Abstract

Three naturally and six mechanically ventilated microenvironments (MEs) of a mix-use commercial building in Delhi are used to study indoor-outdoor (I/O) relationships of particulate matter ≤10 μm (PM10), ≤2.5 μm (PM2.5), and ≤1 μm (PM1). Effect of environmental and occupancy parameters on the concentrations of PM during working and non-working hours (i.e., activity and non-activity periods, respectively) are also investigated. Average outdoor concentration of PM10 and PM2.5 were found to exceed the 24-h averaged national standard values, showing a polluted environment surrounding the studied building. During working hours, indoor PM10 concentration was found 6-10 times, both PM2.5 and PM1 were 1.5-2 times, higher than the non-working hours in the selected MEs. The variations of indoor concentrations were highest (17.1-601.2 μg/m3) for PM10 compared with PM2.5 (16.9-102.6 μg/m3) and PM1.0 (10.6-63.6 μg/m3). The I/O for PM10, PM2.5, and PM1.0 varied from 0.37-3.1, 0.2-3.2, and 0.17-2.9, respectively. The results suggest highest I/O for PM10, PM2.5, and PM1 as 3.1, 2.15, and 1.76, respectively, in all the three natural-ventilated MEs (canteen, kitchen, reception). Irrespective of PM types, the average I/O was <1 for mechanically ventilated MEs compared with >1 for naturally ventilated MEs. As opposed to PM1, better correlation (r > 0.6) was noted between indoor PM10, PM2.5, and CO2 concentrations in most of the airtight MEs. © 2013 Springer Science+Business Media Dordrecht.