Australian Air Quality: Comparison with the US EPA AQI scale.

Posted on September 6th 2014
(re-edited on January 1st 2020)
Share: aqicn.org/faq/2014-09-06/australian-air-quality-comparison-with-the-us-epa-aqi-scale/

The Air Quality data for Perth and Western Australia is finally available after a long waiting time.

The department of Environmental Regulation (D.E.R.) from the government of Western Australia, is now publishing the data on their site: der.wa.gov.au/your-environment/air.

While the link to the DEC site is still not working, the feed can be accessed from this new page.



However, unlike the other territories in Australia, WA DER is not providing the readings in raw ppm and µg/m3, but directly in AQI. The AQI scale used by the WA DER is not the same as the one from the US EPA, which we are using for all the stations reported on the World Air Quality Index project. So this aim of the FAQ entry is to explain how the convertion between the two AQI scales is done.


oOo

The WA DER AQI scale is based on the "National Environment Protection (Ambient Air Quality) Measure standards and goals" (available form this link and this other link), which is defined in the table below. Based on this standard, it is possible to deduct the raw readings from the AQI, which is indicated by the last column in the table;

Pollutant Averaging period Maximum concentration Raw data convertion formula
Fine Particles (PM2.5) 1 day 25µg/m3 Mass = AQI*25/100 (µg/m3)
Respirable Particles (PM10) 1 day 50µg/m3 Mass = AQI*50/100 (µg/m3)
Carbon monoxide (CO) 8 hours 9.0ppm Count = AQI*9.0/100 (ppm)
Nitrogen dioxide (NO2) 1 hour 0.12ppm Count = AQI*0.12/100 (ppm)
1 year 0.03ppm
Sulfur dioxide (SO2) 1 hour 0.20ppm Count = AQI*0.20/100 (ppm)
1 day 0.08ppm
1 year 0.02ppm
Photochemical oxidants
(Ozone, O3)
1 hour 0.10ppm Count = AQI*0.10/100 (ppm)
4 hours 0.08ppm
Lead 1 year 0.50µg/m3 n/a

Actually, surprisingly enough, the WA DER AQI scale is much more strict than the US EPA when the AQI is above 50! Check for this comparitive tables for PM2.5:

Particule
mass
10 µg/m320 µg/m330 µg/m340 µg/m350 µg/m360 µg/m370 µg/m380 µg/m390
         
WA DER
Standard:
0..5050..100100..150150..200200..300300.....
         
US EPA
Standard:
0..5050..100100..150150..200

And this comparison is for the PM10:

Particule
mass
20 µg/m340 µg/m360 µg/m380 µg/m3100 µg/m3120 µg/m3140 µg/m3160 µg/m3180
         
WA DER
Standard:
0..5050..100100..150150..200200..300300.....
         
US EPA
Standard:
0..5050..100100..150

For now, we will keep the using the US EPA standard, simply because it is the one we use for the overall Australia.

We will also post an update later, once enough data has been gathered to do more comparison of those 2 scales. We currently assume that the Air Quality in Western Australia is not just the same as in China, where AQI above 200 is common, and that AQI below 50 should be the norm, in which case the PM2.5 reported AQI should be similar for both scales (assuming that PM2.5 is the major pollutant).




--

Note: This article is part of a series on Worldwide Air Quality scales.

For more information about specific countries or continent, please refer to those articles:
Thailand and Malysia
-
India
-
China
-
Hong Kong / Canada (Air Quality Health Index)
-
South America
-
Australia
-
Quebec and Montreal
-
Singapore
-
Poland
-
Indonesia
.

For information about the 24 hours averaging used or Ozone and Particulate Matter (PM2.5), please refer to those two articles: Ground Ozone Index - PM2.5 Instant Cast

Click here to see all the FAQ entries
  • AQI Scale: What do the colors and numbers mean?
  • Using Statistical Distances for Real-time Sensor Networks Validation
  • Nitrogen Dioxyde (NO2) in our atmosphere
  • About the Air Quality and Pollution Measurement:

    About the Air Quality Levels

    AQIAir Pollution LevelHealth ImplicationsCautionary Statement (for PM2.5)
    0 - 50GoodAir quality is considered satisfactory, and air pollution poses little or no riskNone
    51 -100ModerateAir quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.
    101-150Unhealthy for Sensitive GroupsMembers of sensitive groups may experience health effects. The general public is not likely to be affected.Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.
    151-200UnhealthyEveryone may begin to experience health effects; members of sensitive groups may experience more serious health effectsActive children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion
    201-300Very UnhealthyHealth warnings of emergency conditions. The entire population is more likely to be affected.Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion.
    300+HazardousHealth alert: everyone may experience more serious health effectsEveryone should avoid all outdoor exertion

    To know more about Air Quality and Pollution, check the wikipedia Air Quality topic or the airnow guide to Air Quality and Your Health.

    For very useful health advices of Beijing Doctor Richard Saint Cyr MD, check www.myhealthbeijing.com blog.


    Usage Notice: All the Air Quality data are unvalidated at the time of publication, and due to quality assurance these data may be amended, without notice, at any time. The World Air Quality Index project has exercised all reasonable skill and care in compiling the contents of this information and under no circumstances will the World Air Quality Index project team or its agents be liable in contract, tort or otherwise for any loss, injury or damage arising directly or indirectly from the supply of this data.



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