Characteristics of VOCs Emitted from the Rubber Tire Manufacturing Industry Based on the Inverse-Dispersion Calculation Method

Abstract

This study selected a rubber tire manufacturing factory located in the North China Plain, and conducted ambient volatile organic compounds (VOCs) observation tests, and calculated the emission of VOCs based on the inverse-dispersion calculation method. The monitoring results found significant differences in both VOC concentrations and chemical composition between the up-wind (background) and the downwind receptors. The average concentrations of VOCs measured by the background and receptors were 53.8 μg·m-3 and 127.5 μg·m-3, respectively. Propane (7.2 μg·m-3), cetone (7.5 μg·m-3), nonanal (12.7 μg·m-3), n-butane (4.9 μg·m-3), and acetaldehyde (2.7 μg·m-3) were the dominant components of background VOCs, and nonanal (43.5 μg·m-3), propane (11.4 μg·m-3), acetaldehyde (7.4 μg·m-3), hexane (11.9 μg·m-3), and n-butane (7.3 μg·m-3) were the dominant components of receptor VOCs. The difference in VOCs between the background and receptors is considered to reflect contributions from the factory, the main components of which were of alkanes (31.39%) and oxygenated organic compounds (33.15%). Using the ISC3 model, the relation coefficient γ between the downwind VOCs increment and the emissions of the factory was calculated for each receptor of each test based on the hourly average meteorological conditions during the observation period. Combining the relation coefficient γ with the difference in VOCs between the receptor and the background, we calculated VOC emission amounts from this factory of 152.8±188.2 t·a-1 and a VOC emission factor (EF) for the rubber tire manufacturing industry of VOC 101.9 g·tire-1. Our estimated EF was loser to EF of U. S. AP42 (55 g·tire-1), but greatly lower than the EF of China's reference (900 g·tire-1). Although our calculations had a relatively higher standard deviation, these results are helpful for better understanding the emission of VOCs from the rubber manufacturing industry. Based on our calculated EF, China's national VOCs emissions from the rubber tire manufacturing industry would be approximately 62.13 kt·a-1, which represents a significant potential contribution to ozone formation (130.87 kt·a-1), but the organic aerosol formation potential is small (0.86 kt·a-1).