An overview of health hazards of volatile organic compounds regulated as indoor air pollutants

Indoor air quality (IAQ) standards and guidelines for volatile organic compounds (VOCs) have been stipulated by various national and international agencies. The main purpose of this paper is to establish an overview of indoor VOCs regarding their impacts on human health. Herein, 13 VOCs were designated as indoor air pollutants (IAPs) in the IAQ standards and guidelines. They were further grouped into four types: nonchlorinated aromatic compounds, chlorinated aromatic compounds, chlorinated aliphatic compounds and aldehydes. For this purpose, the present study discusses the criteria for designating VOCs, and summarizes their main sources in indoor environments. Because the occupational exposure limit (OEL) in workplaces has often used as a preliminary basis for establishing acceptable health-based IAQ guidelines in buildings and residences, this paper thus reviews the OEL values, especially in the American Conference of Governmental Industrial Hygienists (ACGIH)-threshold limit value (TLV). In addition, this paper also reviews the information about the classification of carcinogenicity in human by the international agencies for these VOCs. It shows that human tissues, including kidney, liver, leukemia, nasal cavity, paranasal sinus, liver and bile duct, could be more involved in the development of cancers or tumors when people are exposed to these VOCs through inhalation route in buildings over a long period of time.