A shorter stack can still comply with the Air Quality Standards and will cost less to build. However, the engineering designed stack is an integral part of the advanced air emission management system, based on technical studies. Xinyi considers it wise to adopt a prudent approach and plan well ahead by incorporating sufficient technical capability available to comply with even the more stringent Air Quality standards that may be introduced in the years to come. It will be more costly and difficult to retrofit any air quality management system with a shorter stack.
It is anticipated that the MECP may introduce more stringent air emission requirements in the future. It is prudent for Xinyi to have sufficient spare capability available should that be needed for future use, and the current stack height at 100m is appropriate to achieve even higher standards of emissions regulations should they be imposed.