This study, conducted by noise, vibration and acoustics experts Howe Gastmeier Chapnik Limited (HGC Engineering) concludes that there is no direct health risk from wind turbine sound at Ontario’s regulated setback distance.
Ontario is a North American leader in developing ways to control the impact of noise from wind turbines. Our top priority is making sure these projects are quiet where people live and sleep. Based on 40 decibels, Ontario’s limit and 550 metre setback requirements are among the toughest in North America. The World Health Organization says that an annual average limit of 40 decibels is protective of human health.
The Ministry of the Environment can measure sound levels and detect sounds that exceed the stringent requirement from various sources of noise. However, measuring sound levels from wind turbines requires a standard measuring protocol which separates the noise from the wind and other background sources from the noise emitted by the turbines. Environmental officers are trained to use noise meters approved by the International Electrotechnical Commission (IEC) to monitor wind turbine noise, determine sound levels where people live, and assess background sound levels.
Responding to wind turbine noise complaints
Ministry environmental officers assess all complaints about wind turbine noise using a consistent method. A new wind-turbine specific measurement methodology allows us to determine whether noise under various meteorological conditions is exceeding our limits.
When a complaint is received, environmental officers collect information from the complainant about the nature of the noise, timing and its impact (i.e. is it disturbing sleep?). Environmental officers will visit the site of the wind facility to collect information such as:
Based on the information collected, environmental officers may take noise measurements. These measurements, along with observations, provide useful information about the problem at the complainant location and help in understanding what the general sound levels are at these locations. Also, the complainant could be asked to monitor the noise by triggering a 10 minute recording of the noise at times when the noise is considered to be a disturbance. When a minimum of three recordings are available, the ministry asks the wind facility operator to provide information about observed weather conditions, wind speeds, and power output of the nearest turbine for the periods recorded.
Once the data has been obtained, ministry staff will evaluate the findings and determine the appropriate course of action.
Ensuring sound compliance
The ministry uses a progressive suite of enforcement tools to ensure wind farms operate in compliance with approval conditions. This includes both voluntary and mandatory abatement measures to address non-compliance. The manner in which the complaint is addressed may vary from site to site and can include continued noise monitoring, a noise reduction plan and shutting down turbines.
The ministry also regularly inspects projects to ensure compliance. If these proactive inspections trigger the need for additional noise monitoring, the ministry will use the tools in this protocol to ensure noise limits are adhered to by wind farms.