Aldehyde emissions from lime plaster containing vegetable oil

Abstract

Lime plaster applied to walls and ceilings often contains vegetable oil for improving water resistance, and is considered to be harmless owing to its natural origin. The purpose of this study was to assess aldehyde emissions from plaster containing vegetable oil in order to predict the concentrations of aldehydes emitted into the indoor air. A passive emission chamber method was used to observe the emissions of aldehydes from vegetable oil when mixed with sodium hydroxide solution. The findings show that the alkalinity of calcium hydroxide in the plaster would accelerate the formation of aldehydes significantly. Furthermore, aldehyde emissions from the plaster to which vegetable oil was added were tested using a dynamic emission chamber (the small chamber method). A plaster containing soybean oil strongly emitted hexaldehyde throughout the test period. Plasters containing linseed oil or perilla oil strongly emitted propionaldehyde and acetaldehyde. The calculated indoor air concentrations of the aldehydes emitted from the lime plasters containing vegetable oil exceeded the air quality guidelines of the Japanese Ministry of Health, Labour, and Welfare, the Japanese Ministry of the Environment, and the German Federal Environmental Protection Agency. Moreover, these aldehydes are irritants and have unpleasant odours. Therefore, adding vegetable oil to plaster should be avoided to prevent sick-building syndrome.