Abstract
Indoor and outdoor measurements of formaldehyde and the aromatic hydrocarbons: benzene, toluene, ethylbenzene, m,p-xylene and o-xylene (BTEX) were conducted at six offices in a suburban area in Giza, Egypt, during the winter 2003-04 season. The mean indoor level of formaldehyde was 59.79ppb in offices where there was no smoking and 85.01ppb in offices where people smoked. The highest mean level of formalde-hyde in offices without smoking was in a new office, 90ppb, and the lowest, 36.16ppb, was in an old office. During the period of study, in 13.33%, 20% and 16.67% of samples from non-smoking, smoking and total offices, respectively, the level of formaldehyde exceeded the ASHRAE standard of 0.1ppm. The mean indoor concentrations of benzene, toluene, ethylbenzene, m,p-xylene and o-xylene were 4.32, 25.06, 3.60, 9.14 and 4.38ppb, respectively, in the six offices. The mean indoor levels in non-smoking offices were lower, and in offices with smoking, higher than the overall mean. The highest mean levels of BTEX in non-smoking offices were found in a new office, whereas the lowest concentrations were recorded in an old office. Significant positive correlations were found between the indoor concentrations of BTEX inside the six offices, except benzene in non-smoking offices. Benzene had only weak positive correlations with these compounds.