Dust

State highway roading projects can generate dust which has the potential to affect health and become a nuisance to the surrounding public and environment.

Potential sources of dust include:

• Roads and access areas
• Excavation and disturbance of dry material
• Loading and unloading
• Stockpiling of materials

The adverse effects of dust depend on the size of the particles emitted. Human health effects of airborne dust are mainly associated with fine particles (eg smaller than 10 micrometres, PM₁₀). Nuisance effects are most commonly associated with coarser particles (eg larger than 20 micrometres, PM₂₀) and include:

• soiling of clean surfaces
• dust deposits on vegetation
• contamination of roof-collected water supplies
• visibility impacts, which can also be a safety concern for road traffic in extreme dust conditions.

Dust emissions can be mitigated by adopting best practice in construction site management, such as covering exposed areas, using water trucks and wheel washes, and minimizing the number of truck movements.

Guidance on assessing, managing and monitoring construction dust emissions is available in the resources listed below. The Erosion and sediment control guidelines for state highway infrastructure covers dust control and includes complementary guidance about the control of erosion caused by wind.

• Good practice guide for assessing and managing dust (Ministry for the Environment) - November 2016(external link)
• Guide to assessing air quality impacts from state highway projects v2.2 - August 2019 [PDF, 4.5 MB]
• Erosion and sediment control guidelines for state highway infrastructure
• Project monitoring page

For further information contact environment@nzta.govt.nz.