South Asian Air Quality Scales: Malaysia and Thailand

Posted on May 2nd 2015
Share: aqicn.org/faq/2015-05-02/south-asian-air-quality-scales-malaysia-and-thailand

Flag of Malaysia
(Jalur Gemilang)

Flag of Thailand
ธงไตรรงค์, Thong Trairong
Note: This the second article of series on 'Worldwide Air Quality Scales'.

Air Quality for Malaysia has been available for a long time, but unlike other countries, only the composite AQI is provided. The AQI for the individual pollutants such as PM10, Ozone ... is not available, which makes the convertion to the US EPA scale more difficult.


Fortunately, the information about the AQI scale used in Malaysia, also known as API (for Air Pollutant Index) is clearly explained in the document 'A guide to Air Pollutant Index in Malaysia'.

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For the PM10, the API is defined using the following formula (where c is the concentration expressed in micrograms per cubicmeter (µg/m3):
if (c<=50) API = c
if (c>50 and c<=350) API = 50+(c-50)*.5
if (c>350 and c<=420) API = 200+(c-350)*.14286
if (c>420 and c<=500) API = 300+(c-420)*1.25
if (c>500) API = 400+(c-500)

The very good news is that this formula is very close to the US EPA formula, and actually even more strict on the breakpoints level. The set of graphs below give the visual comparison between the US EPA scale and the Malaysian API scale, for both PM10 (left) and Ozone (right).


As concerns the scale for Thailand, there is a very clear explaination available on aqmthai.com. And again, just like for Malaysia, the breakpoints used for the Thai AQI scale are more strict than the US EPA scale, making it an even more safe scale.



Thailand is also having its own color code and AQI levels description, summurized from this table:

US EPAThailand
rangecolorlevelrangecolorleveldescription
0 .. 50
Good0 .. 50
คุณภาพดี (high quality)ไม่มีผลกระทบต่อสุขภาพ (No health effects)
50 .. 100
Moderate50 .. 100
คุณภาพปานกลาง (medium quality)ไม่มีผลกระทบต่อสุขภาพ (No health effects)
100 .. 150
Unhealthy for Sensitive Groups100 .. 200
มีผลกระทบต่อสุขภาพ (there are health effects)ผู้ป่วยโรคระบบทางเดินหายใจ ควรหลีกเลี่ยงการออกกำลังภายนอกอาคาร
บุคคลทั่วไป โดยเฉพาะเด็กและผู้สูงอายุ ไม่ควรทำกิจกรรมภายนอกอาคารเป็นเวลานาน (Patients with respiratory depression. Avoid exercising outdoors. Visitors, especially children and the elderly. Avoid prolonged outdoor activities.)
150 .. 200
Unhealthy
200 .. 300
Very Unhealthy200 .. 300
มีผลกระทบต่อสุขภาพมาก (affects health)ผู้ป่วยโรคระบบทางเดินหายใจ ควรหลีกเลี่ยงกิจกรรมภายนอกอาคาร
บุคคลทั่วไป โดยเฉพาะเด็กและผู้สูงอายุ ควรจำกัดการออกกำลังภายนอกอาคาร (Patients with respiratory depression. Avoid outdoor activities. Visitors, especially children and the elderly. Should limit outdoor exercise)
300 .. 500
Hazardous300 .. 500
อันตราย (danger)บุคคลทั่วไป ควรหลีกเลี่ยงการออกกำลังภายนอกอาคาร
สำหรับผู้ป่วยโรคระบบทางเดินหายใจ ควรอยู่ภายในอาคาร (Visitors should avoid exercising outdoors. For patients with respiratory diseases. Should stay indoors)


For now, the scale used to report Malaysian monitoring stations on the World Air Quality Index project is based on the Malaysia API, and, considering that the API scale is almost similar to the US EPA scale, we do believe that this is not a problem as such. Regarding the scale for Thailand, the values published on the World Air Quality Index project for the monitoring stations in Thailand are based on the US EPA scale.

Note that both countries are only providing 24 averaged values for the PM10, and as explained in this post, using averaged values does not give a proper feedback on the current air pollution level. Fortunatley, this is something which will change in the future, and both countries will start at some point of provide instant hourly readings too.

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Last, and not the least, there is no PM2.5 data for Thailand and Malaysia. Modernizing the monitoring network with PM2.5 sensors can have a significant cost and takes a lot of time. So, while waiting for the respective governements to make the investements needed, it might be worth to considering usign our innovative proposal for Improving Air Quality Measurements using Affordable and low-cost Sensors, which we did for the BAQ 2014 conference.


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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
-
India
-
China
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Hong Kong / Canada (Air Quality Health Index)
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South America
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Australia
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Quebec and Montreal
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Singapore
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Poland
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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
  • Nitrogen Dioxyde (NO2) in our atmosphere
  • Ozone AQI Scale update
  • Kriging Interpolation




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    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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