(1)Approaches of Enterprises at Early Stages

3.progress in Technology-Based Controls

Around 1965, when the technology for reducing sulfur content in fuels had not yet been established, the only way of abating air pollution was to dilute flue gas emissions using taller smokestacks. Since then, due to the earnest efforts of enterprises, a variety of technology-based controls such as dust removal, desulfurization, and denitrification have been established. Above all, flue-gas treatment technologies such as desulfurization and Above all, flue-gas treatment technologies such as desulfurization and denitrification were rapidly and remarkably being improved.
The earliest effort of private enterprises was to heighten their smokestacks. To design the stack to more effectively diffuse or dilute their SO2 To design the stack to more effectively diffuse or dilute their SO2 emissions, they have repeatedly conducted wind-tunnel tests and computer simulations. Yokkaichi has entered upon the so-called "high-stack age".
In 1967, a pilot plant for flue-gas desulfurization was started at a thermal power plant in Complex N0.2, This process employing activated manganese oxide method was developed under a project of the Agency of Industrial Science and Technology of the Ministry of International Trade and Industry.
In parallel with flue-gas treatment, fuel desulfurization techniques have also been developed and adopted on a commercial basis. content in fuel, which was originally around 3% on the average, was successfully reduced down to 1.7% by a fuel oil indirect desulfurization As shown in Figure 2-6.The sulfur content in fuels has been substantially reduced in recent decades by dedicated efforts of petroleum manufacturers.
Yokkaichi's air pollution has been remarkably improved as a result of the introduction of the desulfurizing process and other control efforts extended by some factories such as a switch to high quality fuel with low sulfur content. Yokkaichi's air pollution has been remarkably improved as a result of the introduction of the desulfurizing process and other control efforts extended by some factories such as a switch to high quality fuel with low sulfur content.