Indoor and Outdoor BTEX in the Hospital and University Estates of Ouargla city, Algeria

摘要

Volatile organic compounds are ubiquitous atmospheric contaminants, affecting both indoor and outdoor environments. Attention is overall paid to toxicants, among which mono-aromatic species, in particular to benzene, toluene, ethylbenzene and xylenes are cumulatively indicated as BTEX. Mono-aromatic hydrocarbons were investigated in the air of Ouargla, Algeria, between 2014 and 2015. Measurements were conducted indoors and outdoors at the hospital and university estates of the city. BTEX were enriched from air by means of Analyst-I type diffusive sampling devices, which allowed continuous sampling over weeks. After collection, the samplers were spiked with bromobenzene (used as internal reference compound for analysis) and extracted with carbon disulfide directly in the vessel, then the analytes were characterized by means of capillary gas chromatography coupled with flame ionization detection. Total BTEXs ranged from ca. 41 to 131 μg/m~3; among them toluene (22-87μg/m~3) was the most abundant congener. Benzene, ranging from 12 to 27μg/m~3, always exceeded the limit value imposed by European normative for health preservation purposes (5μg/m~3). At the hospital, the indoor/outdoor BTEX concentration ratio (I/O) exceeded all-the-time 1.0 (range: ~1.5-2.0), which suggested the existence of internal sources for BTEX. This finding was confirmed by the analysis of concentration ratios between the BTEX compounds, which changed from outdoors to indoors as well as with the internal locations examined.