Ways  to
Protect your airways.
Masks, Respirators, Air Purifiers
The first thing to do is not listen to ANYBODY who tries to tell you smoke is not harmful and you don't need to wear a mask.
Unfortunately, we even have some medical professionals still telling us we will magically  get better when the smoke passes. A runny nose, itchy eyes or a cough might subside for some people but what about the Group 1 carcinogens you have breathed deep into their lungs? Ones that have crossed over into their blood stream and then travelled to other organs?  These people are the asbestos denyers.
The science tells us there is no minimum safe level of exposure to particulate pollution.
Adverse health effects of even short-term exposure to ambient air pollution are well documented

If our authorities were serious about protecting people's health they would be issuing the correct certified respirator masks and running clinics right across Australia to make sure people know how to perform a proper 'face-fit'.
At the same time they would be jumping onto fires when they start, to put them out before they turn into campaign fires and kill people.
Health effects from particulate matter occur after exposures of 2-4 hours or less in duration of woodsmoke at the 12 - 29mcg/m3 range  (Koenig et al. 1993)
There are ways that can be explored to protect your airways from smoke.
Some might work for some people and some may not work for others.
The only way is to stop the smoke at the source.
This is what we all should be campaigning for.
What we are being told by the authorities to do....

Lock yourself away inside your house -
This is entirely unsatisfactory.
Whilst people are shut away it is convenient for authorities to continue on with their program to blacken Australia, making more smoke, causing more climate change.
There is no incentive to stop the burning or to put the fires out while those most affected are incarcerated.
People should be able to be outside enjoying, in Tasmania, what the authorities happily claim to be the cleanest air in the world. They can't have it both ways!
Air quality inside on a good day is even known to be about 5 times worse than clean air outside.
This is due to off-gasing of nasties from paint, floor coverings, fabric on furniture, animals, cooking odours, etc. We should not be denied clean air outside.
Most homes are not airtight, i.e. constructed to prevent smoke seeping inside. If they were you would die through lack of oxygen. Negative pressure inside the home can actually suck smoke in.
Depending on the construction, the air inside can become as polluted as the air outside. In a very short time  it can soon equalise, i.e.reach unity.
During smoke events it is not always possible to ventilate your home. In any case the smoke particles settle on your soft furnishings and when your kids play on the carpet or lounge, or are put to bed they breathe these smoke particles in. The inside of your home requires a complete sanitisation to get rid of these particulates.
Go to the supermarket, gym or library -
Rarely are these commercial buildings fitted with super HEPA filters to prevent smoke coming in.
In actual fact building / health regulations can stipulate that a percentage of fresh air must be brought in. This can be as high as 20%.  In comes the smoke too!
Move out of the area -
This is not always possible, especially for the sick, the elderly, or those with animals to look after.
Back to the top
Wear a respirator -
Paper masks or doctor type masks will not protect you from wood smoke.
Respirators vary. Some will afford some protection from smoke, others will not.
Remember it will always be slightly harder to breathe through a respirator than not, but mostly it is not difficult!  Unless it is clogged.
Even with asthma it is better to have an approved respirator on during smoke episodes if you can tolerate it. Please try, it could save your life.

As a rule it will be easier to breathe though a respirator which has two filters rather than one single filter.
It will be more comfortable (not as hot) wearing a respirator that has an exhalation valve.

Surgical type masks or cheap paper masks are unsatisfactory. They do not 'mate to the face'. They do not filter out the fine PM2.5 particulates and gases of wood smoke because masks are primarily made to stop moisture or particles going outwards; they are not really designed to filter air coming in.
Respirators on the other hand are designed to have a face-fit and allow air travel in both directions whilst  filtering the incoming air. Incoming air will take the path of least resistance, this is why we do not want air seeping in around the face without being filtered.

Possibly the best advice is to use a respirator and filters that comply with current respiratory device AS/NZS or NIOSH Standards. It should be written on them but here again there are these extra things to consider...

P1, P2, or N95 (NIOSH) particulate filters on their own are not satisfactory for wood smoke because they only filter out the particles and do not filter out the harmful gases.
Multi gas or activated carbon filters need to be used to filter out the gases. For wood smoke / bush fire smoke these are to be used in conjunction with a particulate filter.

An Activated Carbon filter, or charcoal filter, is a bed of activated carbon typically in granular or powdered block form, and consists of millions of tiny absorbent pores. This air filter has been treated to be extremely porous, and this is the popular filtration against gases, chemicals and Volatile Organic Compounds (VOCs).
The Activated Carbon filter is originally called HEGA (High Efficiency Gas Absorption) filter, and first being used by the British Army in chemical warfare. It removes the gas molecules through a process of adsorption (not absorption). During adsorption, the pollutants stick to the outside of the Activated Carbon filter.
You will find a high-quality Activated Carbon filter to have potassium permanganate or potassium iodide to remove the chemicals, formaldehyde and wildfire smoke much better.

Wood smoke is made up of particulates AND gases.
Remember: An activated-carbon filter cannot remove fine particulates, and a particulate filter cannot remove gases, chemicals or Volatile Organic Compounds (VOCs).
You require both types of filters for wood smoke / bush fire smoke.

The author has worn half face respirators for many years in industry, e.g. dust and fumes, and in a hospital setting, e.g. asbestos or legionella, etc.      Perhaps it is easier to understand what the author wears in time of smoke.....
3M 7501 reusable half face respirator fitted with AS/NZS 1716  3M multigas 6059 ABEK1cartridges and 3M 5925 P2 particulate filters. This setup allows the respirator to be used for other applications, not just smoke. Filters do have a use-by date.
I would never wear P2 3M 8210 or 3M 8110s respirators for bushfire smoke as they do not contain a carbon filter.

Respirators come in various configurations: disposable, reusable, half face, full face, and powered.
3M can be contacted on the web and their health hygenist is the one to talk to about any concerns.
The author declares no financial interest with 3M just that he has satisfactorily used their products for many years and has found 3M excellent to deal with. They should be called 10/10M.

Some people might find it a bit claustrophobic to wear a respirator at first, so this should be practiced during periods of clean air to get a feeling for it. Then when smoke concerns do come you will feel comfortable and can rely on getting clean air without this worry.

It  is important to make sure you do what is called a 'face check' when you put on a disposable or reusable half face or full face respirator. This means being clean shaven, no stubble or beards.
A good face fit is essential, to make sure there is no leakage around the face to allow smoke to bypass the filter and go into the lungs,
A simple proceedure is performed everytime the respirator is put on.
Disclaimer: This page does not contain medical advice. People reading this page should work out what is best for them and act accordingly.
Air purifiers - 
Air purifiers or air cleaners come in many shapes and styles.
You can get purifiers that just fit under your nose, there are some available that you can use in your car, or you can get systems that purify the air in your whole house.

Let us just look at portable air purifiers for home use where you can provide a microclimate of better air quality.
There are things to consider like purchase cost, running costs and noise levels but these are dictated to by the area that you want to be able to enjoy clean air.  Most people would choose just one closed off room to 'clean'.
What you are best to look for in a purifier is that it has: 1) A super HEPA filter, and 2) An activated carbon filter.

It is important to size the output of the purifier to match the room size.
This way you will get sufficient air changes through both filters to purify your air. The machines should indicate its delivery rate on a label attached to the machine. Calculators are available on the web to make sure you are purchasing a machine that will do the job.         
What is the appropriate respiratory protection standard for rural firefighters in different firefighting scenarios?
"To be effective this research should involve the rural fire services, WHS regulators, relevant government agencies, the WHS profession including the AIOH, and led by expert researchers from an Australian university or universities.
This evidence must then be used to inform relevant policy across Australia."
The National Asthma Council's Sensitive Coice information on air purifiers and their approved models can be found HERE.
The author uses an Australian made InovaAir E20

Best air purifier for bushfire smoke removal
3M Bushfire Respiratory Protection - Tech Update.
5 Million Face Masks Being Given Out in India 
These are just P2 masks and appear to be Medium size which are too big for the kids. These masks are not respirators with a good face-fit.
Unfortunately it appears the children will not be very well protected when in smoke, gases or fumes. First published by CNN in an embedded tweet. Click HERE for above:
But in Australia the next day: The government will give 450,000 pandemic masks to bushfire-affected people in Victoria, amid shortening supplies and increasing demand.
The masks will come from the National Medical Stockpile - a strategic reserve of drugs and protective equipment usually reserved for use in the event of a public health emergency such as a pandemic.
5 Million Face Masks Being Given Out in Australia
  Screen shot of PM Scott Morrison's video on 4.1.2020 stating he is providing 5 million P2 face masks.      Click HERE for below:
To achieve as close to 100% protection from wood smoke particulates and gases, a full face mask fitted with ABE, or A1 Form multi-gas filters and P3 particulate filters would be suggested along with a good face-fit check performed.
Nothing beats stopping the smoke at the source
These filters do not have a carbon layer for bushfire smoke
Ionizing Air Purifiers -
There is no ozone emission from air purifiers that use HEPA or carbon filters to scrub the air.
Ionizing air purifiers, because of their electric charge, do create ozone. Consumer reports have warned that they may give off potentially harmful ozone levels
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Credit: MATT Golding
BEWARE - NOT ALL MASKS ARE SUITABLE FOR BUSHFIRE SMOKE
NSW firefighters crowdfunding upgraded face masks amid claims RFS gear insufficient
Further reading:
What should I know about portable air cleaners to clean the air?
This information comes from Indoor Environment Group at Berkely Lab.
Size it for the space. They work better in rooms that are closed from other parts of the house, such as bedrooms. If you don't have enough devices for your entire residence, create one or more clean air zones within your home. The Association for Home Appliance Manufacturers (AHAM) provides https://ahamverifide.org/directory-of-air-cleaners/ with verified clean air delivery rates (CADR. AHAM recommends selecting a unit with a CADR that is at least two-thirds of the floor area of the room; so for a room that is 120 square feet, you should have a CADR of at least 80. If the room is open, a higher CADR is needed.
For large spaces and open floor plan apartments or houses, use multiple units.
If you live in tightly sealed house and you turn off the mechanical ventilation, air cleaners will be effective in larger spaces than the manufacturer guidance. If you live in a very leaky house (typical for older homes), pay careful attention to guidelines.
Caution: Make sure the air cleaner does not emit ozone. Check for "CARB certified."
Caution: don't rely on the "auto" setting. These have low-cost particle sensors that are often not accurate. Operate on highest speed that you can tolerate.
Note that the sizing recommendation is for the unit to operate at the highest speed setting, which will also be the loudest. If you want quieter operation, you can select a unit that is sized for a larger space and operate it at a lower setting.
Berkeley Lab has https://iaqscience.lbl.gov/faq/how-do-i-select-portable-air-cleaner-my-home
June 12 2020 - Parliamentary inquiry into air quality
Long-term protection from masks 'dubious'
NSW Health acting executive director Dr Richard Broome told the inquiry the state distributed about 900,000 P2 masks during the crisis but agreed there was limited research about their effectiveness.