And a new CSIRO report shows that the smoke can actually pose a greater threat than the fires themselves.

From far away bushfire smoke can look spectacular, at worst perhaps a gentle blanket, but when it rolls into town it can kill.

Living near the CBD would make you think you're well out of harm's way when fires rage in the bush, but the residual effects of smoke are a danger, triggering what's termed 'major pollution events'.

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NASA's satellites track bushfire smoke around the globe. A clear picture taken of Tasmania a few days ago is a tell-tale sign that the smoke is thick on the ground.

Closer to earth the air quality in Brisbane this morning was moderate while Sydney and Melbourne's air quality was good. However with eleven fires currently burning in New South Wales, Victoria hosting fifteen and Queensland 24, air quality now hinges on the fire's longevity before those in the cities breathe the fallout.

In 2006 in Melbourne fires burnt in the state's Alpine region for 69 days. The CSIRO'S Dr Mick Meyers studied the city's air quality at the time.

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"A surprising find for those on the frontline is their smoke exposure is manageable, but those of us in nearby regional towns and cities face the greatest health hazard," Dr Meyers said.

The worst smoke is dense and packed with super fine particles, and Melbourne had eight days of it air during the Alpine blaze. The CSIRO found that if Melbourne's entire population had been outdoors during that time the death rate over that week could have increased by ten per cent.

Professor Jo Douglas treats the effects of smokey days as an asthma specialist at the Royal Melbourne Hospital and says "air pollution can have detrimental consequences to health."

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According to Professor Douglas "some people will develop symptoms - so cough or wheeze - and for those people they need their reliever medication at hand. Symptoms can be somewhat delayed after the exposure to the increased air pollution."

It's not just the young or old who suffer on smokey days. When the city air is laden with smoke it spells a challenging day ahead for those with asthma and doctors advise to take your medication, try and stay indoors, and if you're really struggling, call for an ambulance.

"If it's hazy outside that means the concentrations are actually quite high - don't do anything that involves a lot of heavy breathing, stay out of it," Dr Meyers advised.

More stories from reporter Clare Brady

FULL COVERAGE: All the latest on the bushfires

BUSHFIRE INFORMATION

• Advice on how to Prepare, Act, Survive
• Link to current fires and incidents in NSW, @NSWRFS

Fire prone areas in NSW

A statewide total fire ban has been declared for Wednesday 9 January 2013 due to the large number of fires across NSW.

• Advice on how to plan and prepare
• Link to Latest warnings and incidents in Victoria, @CFA_Updates

Danger areas in Victoria

• For information on friends or relatives affected by the Tasmanian bushfires call 1800 727 077
• Current incidents by Tasmanian Fire Service - www.fire.tas.gov.au - @TasFireService
• Tasmanian weather forecast - weather.yahoo.com

A total fire ban is in effect for all parts of Tasmania

• Red Cross Tasmanian Bushfires appeal - www.redcross.org.au, 1800 811 700, or send a cheque or money order with a note that it is for the Tasmanian Bushfires Appeal 2013 to: Australian Red Cross Supporter Service, GPO Box 2957, Melbourne VIC 8060
• Facebook page Tassie fires - we can help
• Federal Government help - The Federal Government has sent a mobile services centre to Tasmania to deliver emergency funding to bushfire victims. Emergency Services Minister Nicola Roxon said those affected could apply for emergency funding of up to $1000 per adult, and $400 per child.
• For more information about the Australian Government Disaster Recovery Payment, go to humanservices.gov.au/disaster or call the Australian Government Information Line on 180 22 66 from 8am to 8pm (local time), seven days.

• Advice to be bushfire ready - have you got a plan?
• Link to current incidents in South Australia, @CFSAlerts

• Advice on your Bushfire survival plan
• Link to current bushfire incidents in Queensland, @QldFire

Fire affected areas in Queensland

• Advice on how to prepare for a bushfire
• Link to alerts and warnings in WA, @dfes_wa

• Advice on NT Fire and Rescue, @ntpolice

• Advice on fire incidents map, @ACTRFS