ABSTRACT

Indoor air quality in urban areas of India is deteriorating in air-conditioned multistoried buildings. Many buildings and restaurants are using ozonization as a solution to odorous indoor environment in air-conditioned spaces. Indoor air quality in terms of Volatile Organic Compounds (VOCs) and ozone levels at nine air conditioned locations, where ozonization units were mounted within the air conditioning ducts, representing cinema hall, restaurant, food courts and office were monitored with and without ozonization system at Mumbai in India. Such type of study is first of its kind for indoor air quality assessments within the public place domains in the city of Mumbai. Air was sampled within the office, cinema hall, restaurant, bar, conference room and food courts with and without ozonization units in operation for a period of four hours. Ozone was analyzed using alkaline potassium iodide method and VOCs were analyzed using USEPA TO-17 Compendium Method. Ambient air was adsorbed on Chromosorb 106 cartridges and VOCs were estimated using Varian make GC-MS subsequent to thermal desorption. About forty VOCs including Hazardous Air Pollutants like benzene, toluene, ethylbenzene, Freon 20, carbon tetrachloride etc have been identified in appreciable concentrations. It was observed that concentration of VOCs reduced when ozonization system was working and residual ozone levels were found to be within the Indoor Air Quality (IAQ) guidelines for office and public places adopted by Hong Kong and World Health Organization (WHO) recommended safe levels. Observed concentration of individual VOCs, considered in IAQ objectives of Hong Kong Government, are much less than guide line values at all locations excepting in case of benzene, chloroform and carbon tetrachloride even without ozonization unit in operation.

Effect of Ozonization on VOC Concentrations In Some Indoor Environments in Mumbai [.doc, 431.6Kb]