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【Volatile Organic Compounds (VOCs)】

Hiroaki Ozaki    

VOCs (Volatile Organic Compounds) are defined by the Air Pollution Control Law of Japan as follows: VOCs are gasified organic compounds that are discharged into the air or flown apart. Substances (Methane and Hydrochlorofluorocarbon) designated by government decree which do not cause suspended particulate matter and oxidants are excluded. There are about two hundred typical VOCs including toluene, xylene, and acetic ether, and one hundred of these substances are listed by the Ministry of the Environment.

VOCs generate photochemical oxidants when they react with NOx under ultraviolet exposure and are involved in the generation of secondary particles of suspended particulate matter (SPM) by photochemical reaction with VOCs, which are released into the atmosphere. SMP can remain in the air for long periods of time because it is very fine. Furthermore, SMP causes human health problems because it settles in the lungs and air tube and creates an adverse effect on respiration organs. Under these circumstances, Western nations, such as the UK, Germany, and other EU countries have already drafted regulations to reduce VOCs to 30-70% of their 1990-2000 level by the year 2010 (the exact figure varies by country). In Japan, discharge control standards for benzene, trichloroethylene and tetrachloroethylene have already been established as specified substances of toxic air pollution. Efforts such as emission control and voluntary efforts by enterprises of VOC emission control by amendment of the Air Pollution Control Law of 2004 have been implemented. A reduction goal of Japan is to reduce the total amount of VOC emission from fixed sources such as factories by approximately 30% by 2010, compared with the VOC level of 2000. .

It was reported that the amount of VOC emission from fixed sources such as factories in Japan was approximately 1.5 million ton/y (FY: 2000). There are various emission sources such as coating compositions, coating painting, and filling stations..

The following six emission sources are targets of the VOC emission control by government decree:
1) Drying facilities used in chemical processing and production
2) Airborne coating and drying facilities used in coating and painting
3) Drying facilities used in adhesion
4) Drying facilities used in printing (web offset printing and gravure printing)
5) Cleaning facilities for industrial products (including drying facilities)
6) Storage tanks (gasoline and crude oil)

Regarding the regulations on each facility, scale requests are established. For instance, in the case of “airborne coating facilities” an air-exhaust ventilator must have an air-exhaust ability of over 100,000(m3/h). Overall, large-scale facilities are the focus of regulation. However, regulations are limited because voluntary efforts by the industry concerning the regulations are highly respected.

Voluntary efforts entail that the sectors (individual enterprises and economic organizations) set VOC emission targets for 2010, create a voluntary action plan, perform measures for emission control regarding selection of raw materials, process management, improvement of facilities, and installation of treatment equipment, and then conduct self-examination and evaluation. The government and municipalities support these voluntary efforts and try to control VOC emission using emission concentration regulations and direct regulations such as operational improvement order. The breakdown of the reduction target of 30% by 2010 is as follows: 10% by direct regulations (control) and 20% by voluntary efforts.

VOC emission conditions, total amount of emission, and emission control are considerably different in every municipality. By 2010, municipalities where high levels of VOCs are generated will establish regulations feasible for each area in order to decrease the total amount of VOC emission by 30%; or they will plan to amend the regulations. Each municipality has different contents of the regulations. However, they try to decrease the total amount of  VOC emission by adding another source to the source list (six emission sources described above) ordained by government decree (e.g., filling stations and dry-cleaning plants) and tightening regulations. However, there is a limit for promoting voluntary efforts for medium and small-scale enterprises and imposing severe legal regulations. The regulations require full examination concerning facilities and their scale.

Under these circumstances, there are challenges for facilities regulation because the regulations do not cover coating compositions used for outdoor buildings which are a significant source of VOC emission. Also, it is not clear how various administrations will be involved in voluntary efforts. In the future, reviewing efforts continuously, using waterborne coating compositions, and other measures for reduction of the VOC emission are crucial.

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