주요 산업시설의 유해대기오염물질 배출특성, 배출량 및 위해성평가

Abstract

Hazardous air pollutants(HAPs) are considered to be a major threat to human health and environmental ecosystem. The HAPs are gaseous, aerosol or particulate pollutants presenting in the air in low concentrations with specific characteristics such as toxicity or persistence. The HAPs are emitted or formed from various sources including industries, incinerators, motor vehicle, wood heaters, cigarette smoke, paints and solvents. Domestic major HAPs emission sources were classified with non-point and point emission industry in this study. Typical five categorizations of industry releasing in large amounts of HAPs were selected to figure out the characteristics and emission amount of HAPs. Furthermore, a basic research for risk assessment to facility workers was performed to figure out the level of HAPs in ambient air around major non-point emission facilities. To perform effective investigation into non-point emission sources, a new sampling method called with 'KOREA blow-though bag method' was developed. This effectual method decreased sampling time by 48% per sample and had 60 times lower method detection limit as compared with former method of US-EPA blow-through method. This new method was used to understand the characteristics and discharging amount of HAPs at respective facilities of domestic major non-point sources. The research subjects for non-point emission sources of HAPs were basic petrochemical manufacturing industry, synthetic resin products manufacturing industry and paint manufacturing industry. The emission of benzene from the BTX facility and SM facility in basic petrochemical manufacturing industry constituted 50%. In case of including toluene, ethylbenzene and xylene, these chemicals occupied over 95% of total emission. There was 1,3-Butadiene with 70% at the BD facility. Furthermore, benzene, toluene and ethylbenzene with 1,3-Butadiene are emitted over 99% of total amount of HAPs. There were various emission characteristics according to detailed production facilities of synthetic resin products manufacturing industry. PVC facility and ABS facility discharged a large amount of HAPs in particular. According total production of PVC and ABS in 2009, it is respectively calculated that PVC and ABS facilities emitted the target compounds about 20 and 121 tons to the ambient air per a year. The major emitted compounds in PVC facilities were vinyl chloride contributing 50% and toluene occupying 20% of the total emission amount. Main compounds discharged from ABS facilities were styrene and acrylonitrile with 40% and 20% of the emission quantity, respectively. Oil-based paint facility and water-based paint facility were classified from paint manufacturing industry. Total emission amount from oil-based paint facility was 600 times higher than water-based paint facility. The major chemical species in oil-based paint facility were toluene, xylene and ethylbenzene with percentage of 25%, 22% and 15%, respectively. On the other hand, butyraldehyde contributing 60% and toluene contributing 14% were main compounds at water-based paint facility. In terms of industry, these analytical results of characteristic and emission amount of HAPs in domestic major non-point sources are able to provide a reference for reducing manufacturing materials and emission of HAPs. Furthermore, the results are able to offer a basic material for source estimation and risk assessment in terms of environment. The emission characteristics and amount of HAPs from the point emission sources were also investigated to the waste incineration industry and Cement manufacturing industry. The waste incineration industry is subdivided into municipal waste incinerator, industrial waste incinerator and specific waste incinerator again, and then municipal waste incinerator and industrial waste incinerator are classified into large, medium and small classes by scale. The municipal waste incinerators with small scale were equipped with inadequate pollution control devices. Thus, the small class waste incinerators discharged 100 times higher concentration of HAPs per unit weight of wastes than the large class waste incinerators. Those small incinerators disposed of 7% of total municipal wastes, nevertheless they discharged 1,200 tons of HAPs per a year. The large and medium scale incinerators had annual emission amount of HAPs as 155 tons and 148 tons, respectively. The major emitted chemicals was HCl contributing 80% of the total emission amount. The small scale incinerator for industrial waste showed discharging rate of 2.7 kg/ton of HAPs which is 13 times higher rate than the large scale incinerator's. The annual emission amounts from industrial waste incinerators by scales were 433 tons for the large, 249 tons for the medium and 813 tons for the small, respectively. The main chemical species from these incinerator was HCl with the municipal incinerators. This research about emission characteristic and amount of domestic point emission sources proposed practical materials to the risk assessment as compared with periodical legal tests. Furthermore, it is suggested that continuous research about the major HAPs should be perform based on this study The risk assessment to field workers was evaluated in ambient air in facilities which were highly contaminated by HAPs of non-point emission sources. Non-point emission samples were collected from the three major non-point source industries. The first was the basic petrochemical manufacturing industry(BTX facilities, SM facilities and BD facilities). The second was the synthetic resin products manufacturing industry(ABS facilities) and the last was the paint manufacturing industry(oli-based paint facilities and water-based paint facility). Assessment of human health risk in terms of carcinogenic and non-carcinogenic hazard risk due to exposure of HAPs has been estimated for workers of the non-point emission facilities using the Monte Carlo analysis. Health risk assessment did not consider fate, transport and behavior of receptor workers and can only be used to estimate relative risk of direct exposure HAPs concentration. Carcinogenic benchmark concentrations were set at a risk level of one-in-one-million(1.0E-06). Hazardous ratios of 1.0 were used when comparing HAPs concentrations to non-carcinogenic benchmarks. Some HAPs exceeded a cancer risk level of 1.0E-06 at the non-point HAPs emission facilities. Benzene and ethylbenzene which are known as raw material for production were found with high concentration in BTX, SM and BD facilities which are composed similar system. This result represents that the workers who work over 5 years are exposed to excess level of acceptable risk(1.0E-06) by US-EPA, and several workers were exposed to criterion of risk level(1.0E-04) according to years of work. Acrylonitrile, 1,3-butadiene, ethylbenzene, formaldehyde and acetaldehyde exhausted from ABS facilities occasionally exceeded the acceptable risk level according to years of work. Furthermore, several substances exceed criterion of risk level due to long time work. Benzene, dichloromethane, ethylbenzene and formaldehyde exceeded level of acceptable risk according to years of work at the oil-based paint facility and formaldehyde and benzene are over the risk level at the water-based paint facility as well. Hazard quotient to non-carcinogenic compounds was also evaluated. Entire target compounds at the whole facilities were not over the level 1.0 presenting a possibility which can cause hazard effect. Because the risk assessment for workers in facilities by HAPs is based on temporary investigation and sampling in this study, the result involves few errors. Thus this result can not be given a indisputable representative. However numerous chemicals having high hazardous risk have to be performed additional researches.

Key words: Hazardous Air Pollutants, Non-point emission sources, incineration, Air emission, Risk assessment, Monte Carlo analysis.