Air pollutants in office environments and emissions from electronic equipment: a review

Abstract

The aim of this review is to evaluate the existing knowledge on the presence of indoor air contaminants in office buildings. The most commonly found chemicals are aromatic compounds (BTEX), linear and cyclic alkanes (hexane, nonane, methyl-cyclohexane, terpenes (α-pinene, limonene), carbonyl compounds (formaldehyde, acetaldehyde) and particulate matter. Concentrations of volatile organic compounds (VOC) in office buildings in Europe and North America are in the range of 0.1-1000 μg/m3, with average concentrations being in most cases <100 μg/m3. Higher concentrations (up to 1600 μg/m3) were measured in Asiatic countries. Thus, concentrations of benzene and toluene in European countries range from 2 to 11.2 and from 4.3 to 43.1 μg/m3, respectively, while, in non-European countries, concentrations range from 3.4 to 87.1 and from 52.8 to 287.3 μg/m3, respectively. Emission rates of chemicals from office equipment (including fax machines, laser jet printers, ink-jet printers, scanners, and photocopying machines) were studied in test chambers. Highest emission rates were obtained for toluene, ethylbenzene, m,p-xylene, and styrene, as these compounds are normally used as solvent in toner for printers. Emissions from desktop computers using CRT or TFT screens include aromatic hydrocarbons, alkanes, alcohols, ketones and aldehydes, particularly formaldehyde, with emission rates up to 103 μg/h per unit. For particles, the PM levels measured in European offices range from 7 to 180 μg/m3 (for PM10) and 5 to 60 μg/m3 (for PM2.5). Indoor/Outdoor ratios ranged from 0.34-0.88 (for PM2.5) and 0.46-1.7 (for PM10). Significant PM levels are generally found during operation of printers, copy machines and multi-functional devices.