Acetaldehyde indoors

Acetaldehyde is a natural product of combustion and photo-oxidation of hydrocarbons commonly found in the atmosphere. It is an important industrial chemical and may be released into the air or in wastewater during its production and use. It has been detected at low levels in drinking-water, surface water, rainwater, effluents, engine exhaust and ambient and indoor air samples. It is also photochemically produced in surface water. Acetaldehyde is an intermediate product in the metabolism of ethanol and sugars and therefore occurs in trace quantities in human blood. It is present in small amounts in all alcoholic beverages, such as beer, wine and spirits and in plant juices and essential oils, roasted coffee and tobacco smoke (lira et al., 1985 Hagemeyer, 1991 United States National Library of Medicine, 1998). 

Exposure to acetaldehyde may occur in its production, and in the production of acetic acid and various other chemical agents. It is a metabolite of sugars and ethanol in humans and has been detected in plant extracts, tobacco smoke, engine exliaust, ambient and indoor air, and in water. 

Some VOCs can be malodorous pollutants, sensory irritants, or hazardous air pollutants. Hazardous VOC air pollutants include acetaldehyde, benzene, carbon tetrachloride, chloroform, ethylbenzene, formaldehyde, hexane, methylene chloride, naphthalene, paradichlorobenzene, pesticides (biocides), styrene, tetrachloroethylene, toluene, trichloroethylene, and xylenes. They are found in essentially all indoor locations, released by off gassing from numerous sources, such as construction and decorating materials, consumer products, paints, paint removers, furnishings, carpets, and from combustion of wood, kerosene, and tobacco. While more than 500 VOCs have... 

Wang (1975) determined indoor air concentrations of several bioeffluents in a mechanically ventilated 2400-m lecture theatre containing 225-389 occupants. These were [with range of average concentrations (pg/m )] ethanol (43-84), acetone (49-70), methanol (37-72), butyric acid (42-54), acetic acid (21-24), phenol (15-18), amyl alcohol (13-27), diethyl ketone (6-20), ethyl acetate (9-31), toluene (7-36), acetaldehyde (2-8) and allyl alcohol (4-9). Many of these were considered to originate from metabolic breakdown of foodstuffs or from food components. 

Gas samples from room air were also detected with PTR-MS to estimate the indoor air quality [4,123]. Samples were taken from five rooms constructed more than 20 years ago. Two rooms had been equipped with new furniture and carpets only 2 months before the measurements were done. The concentrations of formaldehyde and ethanol were quite similar in the old and newly furnished rooms. Acetaldehyde, methanol, propanol, acetone, and toluene were strongly enhanced in the two newly furnished rooms. It was also found that the concentration of formaldehyde in four of the five rooms was higher than the maximum concentration allowed by Austrian law for permanent exposure dose to human [4]. 

Chamber (Caltech Indoor Chamber Facility) experiments have also been carried out by Lee et al. to monitor the time evolution and yields of gas-phase VOCs produced by the ozonolysis of ten different terpenes [197] six monoterpenes (a-pinene, (3-pinene, 3-carene, terpinolene, a-terpinene and myrcene), two sesquiterpenes (a-humulene and p-caryophyllene) and two oxygenated terpenes (methyl chavicol and linalool). Several gas-phase oxidation products were identified including formaldehyde, acetaldehyde, formic acid, acetone, acetic acid, nopinone and pinonaldehyde. 

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