Insights and Analysis

Transboundary Pollution in Northern Thailand Causes Dangerous Levels of Smog

March 26, 2014

By Genevieve Gebhart

Pollution kills roughly seven million people worldwide each year, with air pollution the cause of one in eight deaths, according to the latest data from the World Health Organization released on Tuesday. Asia faces the greatest burden where the majority of the deaths occur.

Chiang Mai smog

Every year between February and April, dry-season aridity and rising temperatures coincide with forest fires, agricultural burning, and other sources of pollution to blanket Northern Thailand in a layer of smoke and haze. Photo by Flickr user Andrew Smith

These latest findings hit close to home in Northern Thailand where, despite promises from local and national authorities for cleaner and safer air, extreme seasonal air quality problems persist in the Chiang Mai-Lamphun Valley. Every year between February and April, dry-season aridity and rising temperatures coincide with forest fires, agricultural burning, and other sources of pollution to blanket Northern Thailand in a layer of smoke and haze.

Chiang Mai, the largest city in the North and second-largest in the country, announced this year’s first day of “unsafe” air quality on March 11. Levels of PM10 (particulate matter of less than 10 microns) rose above the Thai government’s threshold of 120 micrograms per cubic meter (ug/m3). Neighboring provinces have since reported similarly hazardous measurements. By comparison, PM10 in Bangkok has hovered between 40 and 50 during this same period.

Smog in Chiang Mai

These two images were taken from the same spot in Mae Taeng District on the Mae Taeng River, about 50km north of Chiang Mai. The top image is from last December, and the bottom from March 21. Photo/Diana Edelman/d travels ’round”

Thai media and officials often blame the pollution on swidden (or shifting) agriculture. Swidden farmers typically cultivate plots of land in cycles. A particular plot of land is cultivated for a year, then allowed to lie fallow and recover for multiple years before being used again. In the meantime, farmers shift to a different plot of land. In the long term, swidden farmers rotate among several plots, always moving toward old, previously cultivated land. Most swidden farmers burn plots of land in order to clear and fertilize them before planting. This practice typically falls between February and April, during the worst of the haze, and has sparked intense criticism and controversy.

Characterizing swidden farmers as the pollution’s primary cause, however, misses the extensive range of burning activities during this season. In addition to swidden farmers clearing fields, a smaller proportion of farmers may burn land in order to clear forests and expand crop fields, to flush out game, or to trigger the growth of specific mushroom varieties. Further, virtually all methods of farming produce organic waste. The faster, cheapest, and least labor-intensive way to dispose of it is burning, which is common.

Monoculture, the practice of growing a single crop over a wide area, creates especially large amounts of agricultural waste. Thailand’s recent surge in contract farming with agricultural conglomerates like Charoen Pokphand has encouraged intensive monoculture of corn and other cash crops. Ethanol-use policies have added extra incentives with guaranteed high prices for corn. The result has been unprecedented amounts of corncob waste. Chiang Mai Province’s Mae Chaem District alone produces – and burns – over 37,000 tons of corncob waste every year.

The pollution’s sources go beyond farming. Accidental forest and grass fires during this hot, dry season are among the primary sources of smoke. Since February 1, Chiang Mai’s Offices for National Resources and Environment have tracked 979 forest fire sites, with damage to an estimated 5,026 rai (1,987 acres) of national park and reserve land.

Perhaps most critically, pollution sources extend beyond Thailand’s borders. GISTDA (Geo-Informatics and Space Technology Development Agency) satellite monitoring shows clusters of burning “hotspots” across peninsular Southeast Asia. Chiang Mai in particular experiences drastic effects because of its location in the Chiang Mai-Lamphun valley, where smoke from neighboring Myanmar and Laos is prone to settle.

With its transboundary sources, Chiang Mai’s haze problem requires international cooperation. ASEAN member countries have made joint efforts in monitoring, preventing, and mitigating transboundary haze since 1997. In addition to a Regional Haze Action Plan, ASEAN member states adopted the ASEAN Agreement on Transboundary Haze Pollution in 2003. More recently, ASEAN has introduced simulation exercises, management strategies, and zero-burning best practices.

Even with this international framework, local efforts in Northern Thailand have proven difficult to coordinate. Attempts to impose 90-day burning bans, or even offers of a 5,000 THB (about $150) reward for information about outdoor burning, have not produced results.

Inconsistent information also disrupts pollution control efforts. On May 14, PM10 reports for the city of Chiang Mai ranged from 87 from to 129 from Thailand’s Pollution Control Department. The 42-unit discrepancy obscures whether or not the air quality had surpassed Thailand’s official safety threshold of 120, or even the Thai Pollution Control Department’s more conservative threshold of 100.

Moreover, these thresholds are dangerously high compared to international standards. The U.S. and the EU, for example, consider any PM10 levels above 50 unsafe. In adhering to such high thresholds, Thai officials risk delaying action until pollution has already passed internationally acceptable limits. Over 70,000 pollution-related hospitalizations in the Northern provinces as of March 20 suggest that the situation has exceeded any safety thresholds.

The complexity of the pollution’s domestic and international sources demands a wider scale of engagement from local and national authorities. In addition to preventing and controlling forest fires, officials must present farmers and citizens with viable alternatives to burning. This year, for example, the Mae Hia municipality in Chiang Mai started a “natural bank” program through which farmers can deposit organic waste in exchange for composted fertilizer. Programs of this kind show the potential of local partnerships. Moving forward, however, regional cooperation and reinvigorated ASEAN efforts will be vital to managing and eventually preventing future crises.

Gennie Gebhart is a 2013-2014 Luce Scholar at the Chiang Mai University Library in Chiang Mai, Thailand. She studied natural resource and environmental economics at the University of Washington. She can be contacted at [email protected]. The views and opinions expressed here are those of the individual author and not necessarily those of The Asia Foundation.


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