Whereas it is expedient to improve the air quality in general has determined, in accordance with advances in scientific, technological and economic change. And social By virtue of Section 34 of the Act and the National Environmental Quality Act 2535 and the statement of the Prime Minister of 71/2550 dated March 12, 2550, the Committee on the occasion of National Environment Conference. 2/2550 dated 18 January 2550, thus improve the air quality in general. As follows: