(Jalur Gemilang)
Flag of Thailand
ธงไตรรงค์, Thong Trairong
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 EPA | Thailand | |||||
|---|---|---|---|---|---|---|
| range | color | level | range | color | level | description |
| 0 .. 50 | | Good | 0 .. 50 | คุณภาพดี (high quality) | ไม่มีผลกระทบต่อสุขภาพ (No health effects) | | |
| 50 .. 100 | | Moderate | 50 .. 100 | คุณภาพปานกลาง (medium quality) | ไม่มีผลกระทบต่อสุขภาพ (No health effects) | | |
| 100 .. 150 | | Unhealthy for Sensitive Groups | 100 .. 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 Unhealthy | 200 .. 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 | | Hazardous | 300 .. 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. Fortunately, 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 governments to make the investments needed, it might be worth to considering using 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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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
