AIR QUALITY IN SOUTHERN THAILAND DURING THE 2005 HAZE TRANSPORT

1. AIR QUALITY IN SOUTHERN THAILAND DURINGTHE 2005 HAZE TRANSPORT Prapat Pentamwa and Nguyen Thi Kim Oanh Environmental Engineering and Management Program (EEM) Asian Institute of Technology (AIT) December 2006

2. I. Introduction • Several hundred millions hectares of the world’s forests are annually consumed by wildfires and intentional fires (Qadri, 2001) • The fire episode that hit the region during the El Nino drought of 1997-1998 has been particularly severe and most damaging in the recorded history. • The recent serious regional smoke haze in SEA was observed in the beginning of August 2005 when slash-and-burn agriculture and vegetation fires took place on the Sumatra Island of Indonesian and again on October 2006. • Air quality monitoring network of the Pollution Control Department of Thailand (PCD, 2005) has found a high amount of potential harmful small particles in some areas.

3. II.Objectives of the study • To study the air quality in Southern Thailand during the 2005 haze episode • To investigate the haze transport from 2005 forest fires in Southeast Asia: its impact upon Southern Thailand Scope of the study • This study was conducted in the period of June to August 2005 while forest fire burning in Sumatra island of Indonesia. A trajectory analysis and evaluation of air quality data was carried out on Suratthani, Phuket, Satun, Trang and Songkhla provinces of Southern Thailand.

4. III. MethodologyFramework of Methodology • Study Areas • Southern Cities of Thailand • Sutatthani, Phuket, Songkhla, • Satun, and Trang provinces Air Quality Monitoring (June-Aug 2003-2005) Data Collection Hot Spots Images • Data Processing and Analysis • Air Quality Levels, National Ambient Air Quality Standards (NAAQS) • Air Quality Index (AQI) • Trajectory Analysis by HYSPLIT model Note: Haze episode occurred during 1-31 August 2005

5. N Sampling sites map of Southern Thailand Suratthani Trang Phuket Songkhla Satun

6. IV. Results and Discussion Task I: Evaluation of air quality and potential health Impacts Overall air quality • During the haze episode, Criteria gaseous pollutants (SO2, NO2, CO, and O3) of all sampling sites were generally within acceptable limits. • The highest 24h PM10 conc. during the period was 92 µg/m3in Songkhla and 108 µg/m3in Phuket cities. However, during the haze episode (1 -31 Aug 2005), the conc. of PM10 were higher than the non-haze period in the range of 34-108 in Phuket and 18-92 µg/m3 in Songkhla cities. • Though the levels were still below the PM10 NAAQS standard of 120 ug/m3, they were considerably higher than the avearage levels in August, i.e. 39 µg/m3 in Songkhla and 56 µg/m3 in Phuket city.

7. Comparison ofPM10 conc. (24-h-avg) during 2005 haze episode Standard Level 108 ug/m3 92 ug/m3

8. PM10 (24h-avg) of Phuket city in 2003-2005 152 ug/m3 128 ug/m3 Standard Level 108 ug/m3 Comparison ofPM10 conc. (24-h-avg) during 2003– 2005 haze episodes

9. PM10 (24h-avg) of Songkhla city in 2003-2005 Standard Level 92 ug/m3 102 ug/m3 80 ug/m3 Comparison ofPM10 conc. (24-h-avg) during 2003– 2005 haze episodes

10. Comparison of AQI during 2005 haze episode at Suratthani, Phuket, Songkhla, Satun, and Trangcities Unhealthy AQI = 92 Moderate Good

11. Task II: Investigation of Haze TransportHotspots and the Haze During 10-12 August 2005, 287, 11, and 92 hot spots were detected in Sumatra with the southwest monsoon corresponding to the smoke blanketing Southern of Thailand particularly with the peak of PM10 in Songkhla of 92 µg/m3 Malaysia Hot spots Sumatra

12. Task II: Investigation of HazeTransportHotspots and the Haze Several hot spots were still detected in Sumatra. Smoke haze was observed in central Sumatra. On 15 August, NOAA 12 detected 286 hotspots in Riau.Based on these conditions, it might caused peak PM10 in Phuket on 16 August 2005. Malaysia Hot spots Sumatra

13. Task II: Investigation of Haze TransportTrajectories and PM10 observation The first peak of PM10 (92 µg/m3) occurred on 13 August, trajectory traveled from Sumatra island with Southwest monsoon condition coinciding with trajectory originating 11-12 August. Songkhla Malaysia Songkhla Malaysia Sumatra Sumatra Hot spots and Regional surface winds

14. Task II: Investigation of Haze TransportTrajectories and PM10 observation In Phuket, PM10 conc. peaked at 108 µg/m3 (16 August 2005) coinciding with trajectory originating on 15 August 2005 transported from Sumatra with the Southeast prevailing wind. Phuket Malaysia Phuket Malaysia Sumatra Sumatra Hot spots and Regional surface winds

15. V. Conclusions • The smoke haze event observed in August 2005 in the Southern Thailand appeared to be not intensive when all the 24h criteria air pollutants were within acceptable limits of the Thailand NAAQS. • The highest AQI during August 2005 was recorded on “moderate” range health category. • The backward trajectories confirmed that the days with high PM10 levels in the Southern Thailand coinciding with the air masses originated/passed the intensive fire locations in Sumatra. • The transport of haze from the source region to Southern Thailand during this time took only 1-2 days. • Fires in the central Sumatra might be potential transboundary air pollution in Southern Thailand.