Acetaldehyde Removal from Indoor Air through Chemical Absorption Using L-Cysteine

Kyoko Yamashita,Atsushi Mizukoshi,Miyuki Noguchi,Yukio Yanagisawa

doi:10.3390/ijerph7093489

Abstract

The irreversible removal of acetaldehyde from indoor air via a chemical reaction with amino acids was investigated. To compare effectiveness, five types of amino acid (glycine, l-lysine, l-methionine, l-cysteine, and l-cystine) were used as the reactants. First, acetaldehyde-laden air was introduced into aqueous solutions of each amino acid and the removal abilities were compared. Among the five amino acids, l-cysteine solution showed much higher removal efficiency, while the other amino acids solutions didn’t show any significant differences from the removal efficiency of water used as a control. Next, as a test of the removal abilities of acetaldehyde by semi-solid l-cysteine, a gel containing l-cysteine solution was put in a fluororesin bag filled with acetaldehyde gas, and the change of acetaldehyde concentration was measured. The l-cysteine-containing gel removed 80% of the acetaldehyde in the air within 24 hours. The removal ability likely depended on the unique reaction whereby acetaldehyde and l-cysteine rapidly produce 2-methylthiazolidine-4-carboxylic acid. These results suggested that the reaction between acetaldehyde and l-cysteine has possibilities for irreversibly removing toxic acetaldehyde from indoor air.

Highlights

Airborne acetaldehyde is known to have adverse health effects, as exposure to acetaldehyde can induce sensory irritation [1] and acetaldehyde itself is considered a possible human carcinogen [2]
Ozone has adverse health effects for humans, but it reacts with unsaturated volatile organic compounds (VOCs) and generates carbonyl compounds [10], which may contribute as secondary sources of acetaldehyde in indoor environments
Five types of amino acid were investigated for irreversible removal of acetaldehyde from air

Summary

Introduction

Airborne acetaldehyde is known to have adverse health effects, as exposure to acetaldehyde can induce sensory irritation [1] and acetaldehyde itself is considered a possible human carcinogen [2]. The primary source of acetaldehyde in indoor environments is construction lumber [3]. Current methods to remove acetaldehyde from indoor air include plasma oxidation, photocatalytic oxidation and adsorption by activated carbons. The radicals formed by plasma discharge are strong oxidants and degrade acetaldehyde to carbon monoxide and carbon dioxide [8]. These radicals oxidize nitrogen and oxygen simultaneously, generating nitrogen dioxide and ozone, respectively [8,9]. Ozone has adverse health effects for humans, but it reacts with unsaturated volatile organic compounds (VOCs) and generates carbonyl compounds [10], which may contribute as secondary sources of acetaldehyde in indoor environments

Methods

Results

Conclusion