Health monitoring as wind stirs up silt, dust in Hawke’s Bay

Wind blowing silica dust into the air on Monday in Esk Valley. The winds continued on Tues, with gusts up to 48km/h at Hawke's Bay Airport, between Napier and Esk Valley. Photo / Warren Buckland

Te Whatu Ora – Health New Zealand is working with other agencies to assess public health impacts as high winds in warmer weather generate an airborne silt problem in the region.

While less extreme than in recent days, the problem continued on Tuesday when Napier mid-afternoon had the highest temperature in the country.

It was 22.1deg at 3pm, amid winds which peaked during the day at 48km/h at Hawke’s Bay Airport and 124km/h at Cape Turnagain in the extremes of Southern Hawke’s Bay. Winds at Mahi in the north dropped to an early-afternoon peak of 24km/h, from more than 60km/h during the night.

Medical Officer of Health Dr Bridget Wilson said until more was known from air quality monitoring in affected regions, it was important for people to take precautions during times when dust was a significant issue.

“This is particularly important for the elderly, very young and people with heart or lung conditions,” she said, adding there are steps people can take to reduce the amount of dust they inhale.

“When outside in dusty areas wear a well-fitting mask (N95/P2) and eye protection, avoid exercising outside, and wash your hands and clothes after being in contact with large quantities of silt,” she said. “When conditions are very dusty due to high winds, stay indoors if possible and close windows.”

If people were cleaning up dust inside homes or cars, it was important to wipe down surfaces or vacuum rather than sweep, which could “resuspend” dust.

People worried about symptoms should contact their doctor or Healthline on 0800 611 116.

Wilson said Te Whatu Ora continued to work with Niwa and Environmental Science and Research (ESR) to better understand any potential health impacts related to reduced air quality.

“The silt testing programme as part of the Hawke’s Bay Silt Recovery Taskforce (a joint partnership between Hastings District Council and Hawke’s Bay Regional Council) has reassuringly indicated that the likelihood of significant contamination of the silt by heavy metals, herbicides, and pesticides is likely to be very low,” she said.

“However, the dust itself can still be very irritating to the eyes and upper airways, and for those with underlying heart or lung conditions, like asthma, can worsen their symptoms,” Wilson said.

Te Whatu Ora is continuing to conduct routine surveillance for any increase in respiratory admissions and has not seen a significant increase in respiratory presentations to date.

Regional Council Policy and Regulation Group manager Katrina Brunton encourages the community to be cautious about operating heavy machinery on windy days, and said: “If you see heavy machinery being used which is generating significant dust, please report to our pollution hotline on 0800 108 838.”

An interagency group is working together to measure and minimise risk from the increased dust circulating in the air.

The group is aware of the level of concern among communities following the dry windy weather over the weekend which generated dust from the silt deposited during Cyclone Gabrielle.

Representatives from Te Whatu Ora – Health New Zealand, the Hawke’s Bay Regional Council, the Silt Recovery Taskforce, National Institute of Water and Atmosphere (Niwa), WorkSafe and other local councils are co-ordinating their approach to monitor and address the dust when possible.