Living with demolition dust in Christchurch

Although a certain amount of dust in the air will be a fact of life in Christchurch over the next few years as buildings are demolished and vacant sites are yet to be built on, a variety of measures are in place to ensure irritation from dust is kept to a minimum.

Brett Aldridge, Environment Canterbury’s Regional Manager RMA Monitoring and Compliance says as Christchurch moves into the deconstruction and rebuilding phase, dust being blown from the cleared zones may increase over the spring and summer months, especially with the north west winds that sweep across the city.

CERA, Christchurch City Council and Environment Canterbury are actively monitoring across the city to ensure the impact of the dust is kept to a minimum.

There are three main sources of dust. First is dust produced during the demolition process which is addressed by dust mitigation plans which form part of the demolition contract.
These plans are monitored by CERA Project Management Officers and include sprinkler systems, hoardings, water trucks, atomisers and traffic management plans. Cleared sites can also be compacted and dust may be covered over.

Secondly, dust from roading as a result of truck movements which is monitored by CERA which regularly has sweepers and water carts sweeping up sediment from off roadways and damping down what is left within the red zone cordon.

Truck washes have been set up to water down trucks prior to leaving the cordon and entrance exit points for trucks have been reduced to mitigate and reduce potential dust issues in transit after leaving the red zone.

CERA also has a vegetation management plan which will give vegetation cover over cleared land. Regrowth of grass and other plants on domestic sites is proving effective in suppressing dust.

Thirdly is the dust from cleared sites is the responsibility of the owner to control. Generally, sites are compacted and sprinklers and other watering methods are used.

Mr Aldridge says “While many dust-control measures are in place at these sites, the sheer size and number of the sites means realistically there will be dust – it is part of the environment in which we will be living in for the next few years. People who may find they react to dusty conditions should consider taking extra precautions such as wearing masks.’’

Department of Labour Medical Practitioner Dr Andrew Hilliard has written a paper which says based on current available evidence, the risk of health effects from dust, contaminated silt, mould or fungi to residents and to workers involved in deconstruction and reconstruction of Christchurch is likely to be low.

However, responsible workplace and individual measures should always be followed such as appropriate assessment of all work, education of workers about any possible risks, attention to hygiene and ensuring workers wear appropriate personal protective equipment.

Dr Alistair Humphrey says although Canterbury has not seen an increase in respiratory problems since the earthquakes, it is still important for people to reduce their exposure to liquefaction dust wherever possible and seek medical advice if they feel unwell.

“At this stage we have seen no cases of dust-related lung disease that we can attribute to liquefaction dust.”