Levels And Source Apportionment Of Carbonyls In Indoor Air In Hangzhou, China

Carbonyl compounds are ubiquitous in indoor air, which are mainly from furniture, decorating materials, cooking fumes, environmental tobacco smoke, and so on. The understanding of the concentration and distribution of carbonyls in environment is essential for the assessment of health risks and the removal of indoor carbonyl pollutants. In this study, pollution level, possible sources and health risks of carbonyls in public places and residences in Hangzhou were investigated. The characteristics of carbonyls in discharges were examined for the dominant carbonyl sources in detail, such as cooking fumes, environmental tobacco smoke, and so on. The main conclusions of this work include:(1) The pollution levels and the patterns for carbonyl compounds in indoor air of typical public places were investigated. In indoor air of the public places (including shopping centers, supermarkets, furniture store, inter-city bus stations, railway stations and cinemas), the total concentration of carbonyls were 28.9-301.1μg/m3 for total carbonyls. Cyclohexanone was found to be one of the most abundant carbonyls in indoor air; The preliminary estimate of the health risk for staffs, customers and passengers in public places was made.(2) Concentrations of carbonyl compounds in residential indoor air in Hangzhou were determined. Among the bedroom, kitchen and living room, bedroom presented the highest carbonyl levels in summer. While the carbonyl concentrations in the living room were the lowest in winter. The factors, such as temperature, the age of decoration and furniture, which affect the indoor carbonyl concentrations were discussed. The results showed that pollution levels for indoor carbonyls were correlated with temperature. At relatively low temperatures, formaldehyde was the most abundant carbonyls; while at relatively high temperatures (such as in summer), acetone was the predominant carbonyls. In the investigated residences, more than 70% of the residences with 2 years or older ages of furniture and decoration, presented the formaldehyde concentrations in indoor air in summer which were below the nationl standard level. While in winter, the percentage ratio was above 95%.(3) The pollution patterns of carbonyls in the discharges of cooking fumes, tobacco smoke and decorating materials were studied. The carbonyl yields of cooking fumes were related with food, oil and cooking method. Crotonaldehyde was the most abundant carbonyls in the cooking fumes. Carbonyl yields of the sidestream smoke accounted for more than 95% of the total carbonyl yields of the tobacco smoke. Acetaldehyde was found to be the most abundant carbonyls in the mainstream and sidestream smoke. Among the selected decorating materials, glue tends to emit more carbonyl compounds.