State highway construction dust monitoring in New Zealand: Current practice and lessons learned

摘要

Construction dust impacts are a significant potential environmental effect of state highway construction. This paper investigates current practice in managing construction dust emissions for state highway projects in New Zealand (NZ) and considers the effectiveness of this practice as well as the limitations. In recent years, state highway construction dust monitoring required by designation conditions in NZ has lacked a clear purpose and methodology appropriate to effectively assessing and managing the effects of dust. In a case study from the Victoria Park tunnel project, a single reference equivalent instrument in a fixed location was used to try and achieve two different objectives, the first being to use monitoring for active dust control, and the second being to demonstrate compliance with a resource consent condition (often retrospectively) using a reference equivalent method. A state highway project will often be long and linear and therefore a single, fixed monitoring location for regulatory purposes is of limited value over the duration of the project. However, the alternative options are to either have multiple reference instruments or to shift a single instrument numerous times, which is often costly and impractical. Most state highway dust monitoring conditions in NZ require reference equivalent methods and compliance with a 24 hour average TSP limit of 80 ug rrr3. It is recommended that appropriate guidance should be developed on methods for monitoring appropriate short term trigger values to achieve active dust management.