Bushfire Air Quality ACT & Canberra

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Current Air Quality hourly, last update: , next update:
North ACT (Florey): Loading...
Centre Canberra (Civic): Loading...
South ACT (Monash): Loading...
Accurate hourly data courtesy of the wonderful AirRater.org API and app.
Near Real-Time updated:
Note: real-time data is not directly comparable with hourly data.
Real time data comes from PurpleAir monitoring stations. See FAQ to add your own.
Latest News
Beta test of customizable real-time PurpleAir data! (Click the "Customize button"). Mon, Jan 28 11am
Real-time updates added, courtesy of PurpleAir Sun, Jan 13 12pm
Site code available on Github. Additions welcome. Fri, Jan 10 5pm
The ACT Health folks have released a prototype real hourly data graph. Great job guys! Thu, Jan 09 2pm
Graphs 6hr | 12hr | 24hr


Basic Air Quality Info
What is an AQI (Air Quality Index)?

The Air Quality Index (AQI) is a scale of air pollution that gives Canberrans an indication of how clean the air is so we can change our outdoor activities if pollution levels are high.

The AQI levels are as follows:
Very Good
Very Poor
What are PM2.5 particles?

A general term for any atmospheric particle smaller than 2.5 micrometers (μm) in diameter (3% diameter of a human hair).

Bushfire smoke contains large amounts of PM2.5. When reports say that "AQI is really high" or "Air quality is terrible", they're referring primarily to the high PM2.5 concentration.

An excellent further reading: What is PM2.5 and Why You Should Care

Why are PM2.5 particles dangerous?
They contain all sorts of toxins, and are so small that they can penetrate deep into the blood stream and all your body's tissues. Unlike large particles, your body has a much harder time filtering these particles out. Consistent high levels of PM2.5 exposure have been linked to a large number of health conditions, including respiratory trouble, heart disease, depression, and cancer.
Who is most at risk from PM2.5 particles?
Anyone with a respiratory condition, children, the elderly, pregnant women.
If I'm not in an "at risk" group, is it okay for me to breathe the smoke?
Absolutely not. Everyone is harmed by smoke pollution. Even if you don't have any immediate symptoms, prolonged expsoure can cause serious long-term health problems.
If I can't smell smoke, or the air looks clear, does that mean the air is safe?
Not necessarily. PM2.5 particles are so small that they are difficult to smell, or see in the air. I have measured hazardous levels of PM2.5 in buildings which look and smell clear.
If a building has their aircon on, does that mean the air is safe?
Again, not necessarily. Some aircon systems filter out larger (e.g. PM10) particles, and cooler air can often feel nicer. Unless their aircon has the right kind of filter, the building may still have toxic levels of PM2.5. (My local gym had this exact problem. People should not work out in such conditions.)
What is the relationship between AQI and PM2.5 concentration?

Air particles are measured in terms of "micrograms per cubic meter of air" (µg/m3). AQI is a normalized score designed to show the health impact of the current air, and is calculated by taking the maximum of each individual AQI produced for each possible pollutant (there are many other pollutants, such as PM10, VOCs, CO, etc.). Each pollutant uses a different calculation to produce the final individual AQI value (based on concentration and estimated negative health effects of that pollutant).

In the ACT, AQI for PM2.5 is calculated by multiplying the actual particle readings by 4. So a 50 ug/m3 particle concentration would yield an AQI of 200 (Hazardous). Since PM2.5 is the primary pollutant produced by bushfire smoke, during the bushfire crisis the reported AQI value will almost always be based on the PM2.5 levels. During dust storms, for example, the pollutant with the highest AQI is usually PM10, so the final reported AQI will be based off the individual PM10 AQI score (which is calculated based off of the µg/m3 concentration, but using a different formula from the PM2.5 calculation).

Why do other apps and site seemingly report different AQI numbers?
There are several reasons for this:
  1. Even though the actual particle concentration is the same, different groups multiply this number by different amounts to derive their AQI score. Because of this, you can not compare AQI scores between apps or organizations. Instead you need to get that original PM2.5 concentration number.
  2. Many apps pull from the publicly available data on the ACT Health Air Quality page. This data is a 24-hour rolling average of PM2.5 readings, and does not reflect the very latest air quality readings. It can take 12+ hours for the ACT Health numbers to reflect the actual outdoor air quality. Our numbers at the top of this page do not have this problem, and are accurate to the latest hour.
Wait, but the ACT Health site says their numbers are from the last hour?

I've had many folks write in to point this out. While they say their PM2.5 readings are hourly, they are actually the 24 hour rolling average. You can verify this yourself by multiplying their PM2.5 numbers by 4, and getting the exact "24 hour rolling average AQI" value (ie. PM2.5 * 4 = AQI_PM2.5). It took me quite a while to get the real hourly data. (I asked them directly, and they declined to publish it themselves.)

Update: The ACT Health team has started publishing actual hourly numbers on this page. The data are accurate, and timely.

How does your "real-time" data work?
We take data from PurpleAir monitoring stations, which update in real time. Because these stations use many different kinds of sensors, the data from them are not directly comparable with the sensors used by ACT Health. They are, however, reasonably close, and can give you a rapid view on what the air quality is doing right now.
Dealing With Poor Air
How can I deal with the smoke?
In brief (see following questions)
  • Wear a mask outdoors.
  • Avoid strenuous activity.
  • Use an air purifier / filter inside.
  • Seal your buildings to avoid smoke penetration.
  • Monitor your own home's air quality.
What kind of mask do I need?
You need a mask rated for smoke particles. In Australia, this is listed as a P2 mask/respirator. For US products, these will be listed as "N95" or "P100" respirators. You will also need to ensure that the mask has a good, tight fit around yoru face. Read the package for instructions.
Can children wear a respirator mask?
Where can I get good masks?
Bunnings, or your local hardware store. Here's an example at Bunnings. There are also more permanent masks, and even ones with cool colors and styles for long term use. These may also be more comfortable.
What is an air purifier?
A device with a fan which blows air through a filter, designed to remove pollution and toxic particles from the air.
What kind of air purifier do I need for smoke?
You need one which has a "True HEPA filter" (sometimes rated as E11, E12, E13, H11, H12, H13+). Without this kind of filter, the device will not remove PM2.5 from the air.
Can a humidifer work to purify my air?
Maybe slightly, but it's not significant on its own.
How powerful should my air purifier be?

Air purifiers are rated by CADR (Clean Air Delivery Rate) or m3/h (cubic meters per hours). These values are used together with the area/volume of your room to figure out how many times per hour the purifier filters all your air, a number often called the ACH (Air Changes per Hour).

You want your purifier to filter all the air in your room at least 3 times per hour, though 5+ times is ideal. I have created a simple Air Purifier Power Calculator which can help you figure out what CADR (or m3/h) rating works best for your room/house.

What if my house/room is too big for my purifier?
Every little bit still helps. You may also want to move into a smaller, or more airtight room. The more airtight your house is, the more effective your purifier will be.
How can I make my house more airtight?
  • Close external vents and windows.
  • Seal corners of window with masking tape.
  • Cover areas of airflow with wet towels.
What if I don't have an air purifier?
  • If you have ducted heating, you can put your heater on FAN ONLY setting. While most heating filters aren't HEPA rated, they can still make things a little better.
  • Wet towels: hang them in front of fans, over your ducted heating (see above), etc. Blowing air through/over them will filter out some of the smoke.
  • Run your stove rangehood fan – the carbon filter in there may filter out some smoke.
Should I use an evaporative cooler during heavy smoke?
Evaporative coolers require open doors/windows, and are not recommended to use during smoke haze.
How can I monitor my own home / environment's air quality?

Consumer air quality monitors are nowhere near as accurate as lab equipment, but they can still be useful to get a sense of how bad it is, and to measure changes in conditions, such as when more smoke rolls in, or you've set up a new purifier in your home.

I personally use the Temtop M10 Air Quality Monitor, and have found it to be convenient, portable, and accurate enough for personal use. When I turn on my purifier in my bedroom, for example, the numbers dropped from 600 (outside) to about 5 over the course of 25 minutes. (See this tweet for an example, tracking incoming smoke.)

Can I get air quality data in an app?
Yes, the AirRater app has hourly air quality readings. You can save your location and have the app notify you when the air starts getting bad.
Can I help with measuring air quality?

Yes! The PurpleAir service makes air quality sensors you can install around your home. Data from here shows up on their map in real-time, available to all. If folks all around the ACT did this, we could have accurate AQI numbers for the entire state!

The Aqicn network also has some good monitoring stations you can set up, though there aren't any running at present in the ACT, maybe you can be the first!

ACT Fire Status
Twitter: @CanberraAir
Email: canberra.air.quality@gmail.com
Facebook: CanberraAir
Github: CanberraAir

Please feel free to contact me with questions or comments. If you've thought of a way to help out during this crisis, I'm interested to hear about it!