Dust clouds in the dry summer months have always been an annoying side of driving on country gravel, especially in Kaipara; the land of the long rocky road. However a recent report shows that for one local route, the quantity of disturbed dust becomes so immense, it is classed as a health hazard.
Northland Regional Council’s (NRC) July 20 report, Ambient PM10 2019/2020, which monitored airborne dust along selected Northland country roads, shows that at certain times last summer Hakaru’s Settlement Road recorded over three times the limit of safe levels of PM10, aka ‘particulate matter’ – tiny liquid or solid specks such as fumes, smoke, mist, fog, sea salt and dust. Measuring a mere ten microns or less [1 micron = .0001 centimetre] PM10s are small enough to be inhaled and research has linked respiratory systems such as coughing, sneezing and irritation of the eyes, asthma, bronchitis, hay fever and respiratory illness, to prolonged exposure of ‘suspended particles’ or airborne dust.
The 2020 report states, ‘The National Environmental Standard for air quality set by the Ministry for the Environment for PM10 in order to protect human health is 50 mg/m3 averaged over a 24-hour period’.
However from February 5-14 2020, the PM10 daily average for Settlement Road registered between 70 to 170mg/m3, with the number peaking between the rush hours of 6-8am and 1-4pm. ‘PM10 in the atmosphere originates from both natural and human caused activities’, and levels dropped in the last three days of monitoring once the wind direction changed from a south westerly to east-north easterly… which ‘made the location of the deployed monitor upwind from the road’.
Other roads monitored
explanatory factors for the exceptionally high PM10 include ‘Settlement having a higher traffic volume… and the monitor was located at a property close to the road’.
A Settlement Road resident, who asked to not be identified, has held concerns for some time regarding the dust along the rural metal road, which links Hakaru to Kaiwaka and is often used as an alternative commuter route, and says she ‘did not require a report to tell her the air was dusty’.
“But I was surprised at the extent of the report’s findings, and the monitoring was not even on the busy part of Settlement… I have no doubt that the PM10 recording would be a lot higher there.”
Danger to health
After reading NRC’s report the resident says she tried to contact the council several times about the dust issue but as yet has only been answered with ‘generic responses’.
“What surprises me the most is Kaipara Council have been aware of the issue since July, I would have thought council would have an ethical and moral obligation to notify Settlement residents of the danger to their health caused by dust from an unsealed road that is managed by them… but they have failed to do so,” she says. “Settlement Road needs immediate emergency work to bring these dust levels under control for the health and safety of the residents.”
Work planned says council
“With 1,574km of roads to manage, the traditional mechanisms for addressing dust are expensive and unaffordable… alternative options needed to be considered,” he says.
“Work is currently underway as to how we manage our unsealed network to improve the pavement structure, longevity, ride quality and dust, and to determine if a policy could be developed similar to our existing seal extension policy.”
Money from the Provincial Growth Fund has been allocated to allow a process of applying a ‘wearing course’ to unsealed roads which consists of a blended material ‘that holds together better and produces less dust’.
“While this will not eliminate dust from our unsealed network it will see a reduction. With a network of 1,119km of unsealed roads, this will occur over a number of years,” Hope says. “In regards to Settlement Road, work is planned for Nov/Dec this year on three sections of the road, subject to favourable conditions.”
Council have also embarked on a speed limit review in the Kaiwaka/Mangawhai area, with technical documents showing there is a need to reduce speed on unsealed roads, and are currently seeking public feedback on the proposed speed limit changes.
“Work can then progress around encompassing the views of the submissions and the technical demands of the roads, to see if the recommendations of the technical report can be implemented,” Hope says. “If this change is adopted it will also provide a reduction in the speed of vehicles travelling on Settlement Road and, in turn, the amount of dust being generated.”
Traditional dust preventions are unaffordable says council, but work is planned on some sections of Settlement Road prior to Christmas. PHOTO/JULIA WADE
“Settlement Road needs immediate emergency work… for the health and safety of the residents.”