Indoor particulate matter exposure and correlation of PM2.5 with lung efficacy and SpO2 level of Dhaka City Dwellers

This study investigated indoor exposure of particulate matter (PM) at six residential homes in Dhaka, Bangladesh, to assess the degradation of indoor air quality (IAQ) by PM1.0, PM2.5 and PM10, as well as correlate indoor PM2.5 with occupants' lung efficacy and blood oxygen saturation (SpO(2)). Concentrations of indoor and outdoor PM were monitored individually at day and night using IGERESS Air Quality Monitoring Detector. Mean concentration of indoor PM1.0, PM2.5 and PM10 were 91.7 +/- 47.2, 121 +/- 62.4, and 140 +/- 72.0 mu gm(- 3), respectively. Indoor PM of all size ranges at night were found to be 1.69 times higher than their corresponding daytime concentration. Mean I/O ratio (I/O-day= 0.95 and I/O-night= 0.93) and strong positive correlation (R-day(2)= 0.90 and R-night(2) = 0.80) between indoor and outdoor PM confirmed infiltration of polluted outdoor air inside the households. Indoor sources had 11% and 14% contribution to indoor PM during day and night, respectively. For Cantonment site, PM measurement was conducted during haze and non- haze weather. Haze- time PM concentration was 1.55 to 1.86 times greater than the non- haze period, which indicated that despite the same indoor environment, infiltrated outdoor PM during haze deteriorated IAQ. The average peak flow rate and SpO(2) of 30 inhabitants in six sampling households were 353 L min(- 1) and 98.7%, respectively. Peak flow rate showed strong, negative correlation (R-2 = 0.82) with indoor PM2.5 concentration, which implied that inhalation of excess PM2.5 was probably responsible for the reduced lung function of the residents. However, no association could be established between SpO(2) and indoor PM2.5 concentration. These outcomes indicated severely compromised IAQ in urban Dhaka households, so necessary measures are required to reduce the extent of indoor air pollution.