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

Posted on September 6th 2014

The Air Quality data for Perth and Western Australia is finally available after a long waiting time: The department of Environmental Regulation (DER) from the governement of Western Australia, is now publishing the data on their site: 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.


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;

PollutantAveraging period Maximum concentrationRaw data convertion formula
Fine Particles (PM2.5)1 day25µg/m3 Mass = AQI*25/100 (µg/m3)
Respirable Particles (PM10)1 day50µg/m3 Mass = AQI*50/100 (µg/m3)
Carbon monoxide (CO)8 hours9.0ppm Count = AQI*9.0/100 (ppm)
Nitrogen dioxide (NO2)1 hour0.12ppm Count = AQI*0.12/100 (ppm)
1 year0.03ppm
Sulfur dioxide (SO2)1 hour0.20ppm Count = AQI*0.20/100 (ppm)
1 day0.08ppm
1 year0.02ppm
Photochemical oxidants
(Ozone, O3)
1 hour0.10ppm Count = AQI*0.10/100 (ppm)
4 hours0.08ppm
Lead1 year0.50µg/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:

10 µg/m320 µg/m330 µg/m340 µg/m350 µg/m360 µg/m370 µg/m380 µg/m390

And this comparison is for the PM10:

20 µg/m340 µg/m360 µg/m380 µg/m3100 µg/m3120 µg/m3140 µg/m3160 µg/m3180

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 soon (by October 2014), once we have gathered more data, 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 Chinam, 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). But for now, those are all assumptions, so let's see in one month one enough data is available.


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

For more information about specific countries or continent, please refer to thoses articles:
Thailand and Malysia
Hong Kong / Canada (Air Quality Health Index)
South America
Quebec and Montreal
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
  • Nitrogen Dioxyde (NO2) in our atmosphere
  • Ozone AQI Scale update
  • Kriging Interpolation

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    대기 품질 및 환경 오염 측정에 관하여 :

    대기 품질 지수 단계에 대하여

    0 - 50좋음대기오염 관련 질환자군에서도 영향이 유발되지 않을 수준
    51 -100보통환자군에게 만성 노출시 경미한 영향이 유발될 수 있는 수준
    101-150민감군영향환자군 및 민감군에게 유해한 영향이 유발될 수 있는 수준
    151-200나쁨환자군 및 민감군(어린이, 노약자 등)에게 유해한 영향 유발, 일반인도 건강상 불쾌감을 경험할 수 있는 수준
    201-300매우나쁨환자군 및 민감군에게 급성 노출시 심각한 영향 유발, 일반인도 약한 영향이 유발될 수 있는 수준
    300+위험환자군 및 민감군에게 응급 조치가 발생되거나, 일반인에게 유해한 영향이 유발될 수 있는 수준
    (Reference: see

    대기 품질과 오염에 대해 더 많은 것을 알아보려면 위키피디아의 공기품질 문서(영어)을 보거나 공기 품질과 건강에 대한 AirNow 가이드(영어)를 참조해보세요.

    베이징 의사 Richard Saint Cyr MD의 건강 관련 팁을 보려면 에 블로그를 확인하세요.

    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.


    언어 설정 :

    Temperature unit: