Ambient Air Quality Monitoring and Reporting
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The Pollution Control Department is operating a comprehensive ambient air monitoring network consisting of more than 50 monitoring stations throughout Thailand. This makes the network one of the largest in the world.

In contrast to the previous situation, from 1997 (B.E. 2530) the data is gathered at four regional centres as well as from the central PCD in Bangkok. The regional centres are located at Chiang Mai (North Node), Khon Kaen (Northeast Node), Chonburi (East Node) and Songkla (South Node). The regional centres are located together with the Office of Environmental Policy and Planning (OEPP).


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The regional offices are responsible for the handling of the local data. The data is also transferred to the PCD in Bangkok for handling at a central level.

Regular service and maintenance of the monitoring stations in addition to validation and checking of the data on a daily basis ensure a high quality.

Different ambient air pollutants are measured. Some of them, such as:

  • SO2 (Sulphur Dioxide)
  • NOX (Nitrogen Dioxide)
  • CO (Carbon Monoxide)
  • O3 (Ozone)
  • TSP (Total Suspended Particulates)

are also included in the Thai Ambient Air Quality Standards.

Meteorological information is also measured at many of the monitoring sites, which increases the capability to analyze the pollution situation.


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The graph to the left shows the SO2 values at two of the monitoring stations in Chiang Mai and Lampang in February 1996. Ambient air quality pollution levels vary a lot over time.
The peaks seen in the graph are probably caused by unfavourable combinations of high emissions and meteorological conditions.
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The graph to the left shows a summarized report for a month based on the same data as above.
By interpreting the graph, and at the same time knowing that the Thai Ambient Air Quality Standard for SO2 is 780 mg/m3 for 1-hour averages, it is possible to see that the Standard has not been exceeded during the period despite the incidents with very high pollution levels.
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This graph displays the variation of NO2 and O3 over the day (24 hour period) in the Rayong area.
The monitoring station is located rather close to heavy traffic and industrial areas. It is possible to see the increase in traffic in the morning hours causing NO2 pollution.
The variation of NO2 in relation to O3 levels is caused by chemical reactions.

Please click on the part of the project (function) of your interest for further information:

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