Bushfire Smoke Prediction - Why, How, and What Should We Do With It?

Why does smoke matter?

Bushfires release a large amount of particulate matter, or smoke, and this smoke is small enough to be easily carried on the wind. There is significant research available to show that the most health-significant particulate matter is less than 2.5 micron (the width of spider silk) size. These particles can get easily through our bodies self-protection mechanisms and can cause serious breathing difficulties in even the healthiest people at high concentrations.

The recent joint statement from the CAHA says that the state and federal governments are not doing enough to let people know about the risks of smoke and air-quality or to take control of the situation.

How well can it be predicted?

Once we understand the amount of particulate matter (smoke) released, there are well researched packages, such as HYSPLIT, that can model the dispersion of that particulate fairly well at a high level (resolution of hundreds of metres) based on publicly available weather data and forecasts. A limitation however is in the fire spread, where intense heat can create micro-climate that affects the fire propagation, and hence smoke generation, location, and quantity. This can limit the lead time for planning, with accuracy for nearby fires being limited to just hours ahead of the smoke reaching a major city.

While our ability to conquer nature, as clearly demonstrated by the current bushfires, is limited, it doesn’t mean nothing can be done when we know smoke is heading our way. In fact, we believe planning can be made months in advance to predict, for a given smoke quantity and wind direction, where the worst affected locations in a high-rise city will be.

Some nifty work done by my colleagues (https://ow.ly/pLhR50xAMGF) is ideal in solving this challenge. Such detailed modelling could be really helpful in understanding the impact on localized smoke levels, such as in an enclosed stadium, or around the coastal area where most of Sydney’s livelihood resides. In short, detailed computer predictions using CFD (computational fluid dynamics) can be used to create a database for a smart planning tool, that can be deployed as soon as accurate smoke spread information is available.

What information is already shared?

The tools available to model the smoke and see what’s happening, as shown in the images below, are relatively straightforward to use. The real challenge then is in delivering the message effectively to the broader community.

The state government already share the current and forecast air quality levels (e.g. https://bit.ly/2rO4O3F), and there is also guidance available from that page to tie that back to what it means for people. There are also links to recent satellite data (as shown above) showing where the smoke currently is thickest, and what its recent course has been.

So the information is available, what’s the problem?

Whilst the information is available, it is not being communicated well enough, and no real action or ownership is being taken. This significant ecological and health challenge is now so firmly tied to climate change that any action for the smoke is an implicit criticism of the government climate change policies. Bold action is required and there needs to be a broad acceptance that we all need to be adaptable and forgiving of change to manage the current bushfire problems.

I think that this is a prime example of where a good risk communication strategy supported by straightforward engineering, such as we have delivered to other clients, can help manage expectations and support decision making. Abnormal situations, such as in Sydney now, can then be managed with clear and straightforward directions. This could be decisions to close schools, to minimize unnecessary car travel in the city, and maybe even reconsidering the plans for large firework displays. Such steps would demonstrate a clear understanding of the situation, a willingness to be transparent in sharing that information, and a clear leadership of the situation to reassure people that their fears are not being ignored.

How can we help?

Our company mission is to help organisations deliver innovative engineering to make lives more secure, safe, sustainable, and affordable. To do this, we are constantly pushing the boundaries of what engineering can do, and looking for new ways to apply engineering to solve the challenges we face as a society. In this instance, that could be in helping the government communicate the risks more clearly and understandably, providing detailed modelling on the localized effects for businesses, or providing the engineering insight to convert policy into practice. Whatever problem is presented, we are ready and keen to rise to the challenge.

Various simulations/views of the Fire near Katoomba