Acetaldehyde in the indoor environment

Abstract

Acetaldehyde is a very volatile carbonyl compound with a boiling point of 20.1 °C. The industrial importance of acetaldehyde is comparatively small and tends to decrease. Nevertheless, the substance is ubiquitous in the environment, because acetaldehyde occurs in many chemical and biological processes as an intermediate and byproduct. Acetaldehyde plays an important role in atmospheric chemistry, it is formed during combustion and from the oxidation of fats and oils. Acetaldehyde primarily occurs in the metabolism of plant and animal organisms. Due to the diverse chemical reactions, there are a large number of potential sources, which means that acetaldehyde is also important for the indoor environment. Building products are often rich in fatty acids, which slowly decompose under the formation of aldehydes. Sources from human activities include the preparation of food, burning of candles, wood, and ethanol, as well as the consumption of cigarettes and e-cigarettes. Many other products and devices can release acetaldehyde, the human respiratory gas must not be disregarded, and acetaldehyde is present in outdoor air. Several organizations and institutions regard acetaldehyde as a priority indoor pollutant. This is due to its acute and chronic effects, but also to its classification as a carcinogenic substance. There are sufficient data for acetaldehyde in the atmosphere, as the substance is easily accessible analytically using the DNPH method and is thus often recorded in measurements. Nevertheless, to date, there has been no scientific work that comprehensively characterizes and evaluates acetaldehyde indoors. From the point of view of the necessity of such a summary, an overview of the properties of acetaldehyde and the most important reaction mechanisms is given, followed by a discussion of potential sources and indoor air concentrations. Finally, a health-related assessment of the substance is provided on the basis of indoor guide values.