VOCs Levels in Indoor and Outdoor Residential Homes in Helwan, Egypt

VOCs measurements in indoor and outdoor residential homes, located in four residential sectors of Helwan city, south Cairo, Egypt, were conducted during 2010-2011. VOCs samples were collected according to a standard method developed by NIOSH using activated charcoal tubes and analyzed by GC/FID. The highest ambient VOCs level was determined in site 2 (Helwan city center/commercial/residential area) reaching 102.63 mu g/m3. The highest VOCs levels were recorded in winter and autumn seasons, while the lowest values were found in summer. The maximum VOCs levels in indoor air were measured at site 1 (Helwan city center/residential area) reaching 77.3 mu g/m3. The highest indoor VOCs levels were observed in winter, while the lowest values were found in summer. Indoor annual mean concentration of total VOCs was higher than outdoor (I/O ratio) at sites 1 and 4 (Torra/popular residential area), more than 1.5 which indicates the role of both indoor and outdoor sources at these sites. I/O ratio for annual mean concentration for individual VOCs was higher than 1 for most VOCs which indicates that the air inside Egyptian homes is affected by both indoor and outdoor sources. For some VOCs, I/O ratio was higher than 10 (e.g. Toluene and 1,3,5 Trimethylbenzene at site 1) which indicates dominant indoor sources for these pollutants at site 1. This study shows the impact of indoor and outdoor sources on air inside homes and indicates that the high levels of VOCs in indoor air are sufficient to represent a degree of risk to the residence population