The
World Bank estimates that deaths in Thailand attributable to air pollution have risen from 31,000 in 1990 to roughly 49,000 in 2013. ,
Mae Tha District, Lamphun. Every year mountain forests are set on fire by farmers to increase the yield of the valuable fungus
Astraeus odoratus Industrial growth has created high levels of air pollution in Thailand. Vehicles and factories contribute to air pollution, particularly in Bangkok, which experienced high levels of air pollution in the winter of 2019. Recent research (2019) points to agricultural burning as the root cause of PM 2.5 pollution in Thailand. PM 2.5 is a measurement of
particulates in the atmosphere smaller than 2.5 microns. The
Bangkok metropolitan region, which consists of the
Bangkok Metropolitan Administration (BMA) and the four surrounding provinces (Nonthaburi, Pathum Thani, Nakhon Pathom, and Samut Prakan), holds about 20% of the national population and over half of the country's factories. Due to a lack of treatment facilities, increasing volumes of hazardous substances generated by industrial activities have caused serious dumping issues. Unless treatment facilities are built and institutions starts to regulate strictly, environmental contamination caused by
hazardous waste threatens to become Thailand's worst environmental problem in the future. Thailand's Pollution Control Department (PCD) and other agencies have developed standards in order to reduce air pollution. The standards focus on shifting to lower-emissions vehicle engines and improving public transportation. In 1999, 80% of the motorcycles on the road in Bangkok had environmentally unfriendly two-stroke engines. Diesel trucks and buses also contribute many pollutants. In most areas of the country, air pollutants for vehicles are now within acceptable levels according to national standards. Factories and
power plants have been required to reduce emissions. In 2002, Bangkok and the rest of the
central region contributed between 60 and 70% of the country's industrial emissions. Most power plants rely on burning
fossil fuels. Other sources of air pollution include
garbage burning, open cooking, and
agricultural burning practices, including deliberate
forest fires. Agricultural burning in Southeast Asia often creates
haze. In 2003 Thailand ratified the
ASEAN Agreement on Transboundary Haze Pollution to reduce the haze from forest fires, but issues throughout the region are still common.
Wildfires are started by local farmers during the dry season in
northern Thailand for a variety of purposes, with February and March as the two months when conditions are at their worst. In research conducted between 2005 and 2009 in
Chiang Mai, average
PM10 rates during these months were found to be well above the country's safety level of 120 μg/m3 (microgrammes per cubic metre), peaking at 383 μg/m3 on 14 March 2007. They are the main cause of the intense
air pollution in the
Thai highlands and contribute to the
floods in the country by completely denuding forest
undergrowth. The dry forest soil leads to lower water intake for trees to extract when the rains arrive. In February 2016, Director-General Chatchai Promlert of the Disaster Prevention and Mitigation Department, said that the haze affecting northern Thailand has reached levels that can be considered harmful to health. He said that the Pollution Control Department had reported that the levels of
particulates measuring less than 10 micrometres—known as PM10—had crossed the prescribed safe threshold of 120 in four out of nine provinces where monitoring was conducted. The level of PM10 in the nine regions—Chiang Rai, Chiang Mai, Lampang, Lamphun, Mae Hong Son, Nan, Phrae, Phayao and Tak—was measured at between 68 and 160. The haze level was considered unhealthy in Chiang Mai, Lampang, Lamphun, and Phrae Provinces. During the burning season 2016 (February–April), air pollution has shown no improvement despite the government's purported efforts to ameliorate the burning. The
Mae Sai District of
Chiang Rai Province recorded a record 410 μg/m3 of harmful air particles in the early morning of 25 March 2016. From January–July 2016 the five Thai cities with the highest annual average concentrations of
PM2.5 were Chiang Mai, Lampang (Mae Moh), Khon Kaen, Bangkok and Ratchaburi. Seven out of the eleven cities measured (63.6%) did not reach the National Ambient Air Quality Standard annual limit of 25 μg/m3 for PM2.5 and all 11 cities measured did not reach the
World Health Organization (WHO) guideline annual limit of 25 μg/m3. Thailand's national air quality standards are weak when compared to WHO recommendations. In the first six months of 2017,
Greenpeace Thailand monitored PM2.5 in 14 provinces, as they have done since 2015, and found that every station recorded levels higher than the WHO recommendation of less than 10 milligrams per cubic meter of air. PM2.5 refers to airborne particulates smaller than 2.5 microns, particles so small that they can be inhaled into the blood system and cause cancer and heart disease. Chiang Mai, Tak, Khon Kaen, Bangkok, and Saraburi were among the worst cities with the highest PM2.5 levels in 2017. In February 2018 and 2019, Bangkok suffered under a haze of smog and ultra-fine dust. The Pollution Control Department issued warnings that particulate levels had soared to 94
micrograms per cubic metre of air in some areas, almost double the safe limit of 50 mcg. Residents were urged to wear N95 or KN95 protective dust masks. Bangkok City Hall reassured residents that conditions will "permanently improve" in 11 years (2029) with the launch of many new and improved modes of public transport. Bangkok City Hall failed to mention that it is constructing 1,047 km of new roads due to be completed by 2029 or that in the decade 2008 to 2018 the number of cars registered in Bangkok rose from 5.9 million to 10.2 million. In January 2019, Bangkok authorities employed
cloud seeding to ease air pollution in parts of the city. That month, high-pressure cannons were blasted around Bangkok's City Hall and other areas to combat the smog, leading to debate as to whether the method was effective at washing away the particularly harmful smaller particles. In January 2020, a National Institute for Development Administration survey showed that "81% of the 1,256 local residents questioned agreed that the [Thai] government" was ineffective at solving Bangkok's air pollution, with 2.7% of respondents approving the government's efforts.
Field and forest burning Fires in Thailand fall into three main categories: forest fires, agricultural burning, and roadside burning. Forest fires are set deliberately, as they are thought to increase forest product yields, especially the earth star mushroom (
Astraeus hygrometricus (Pers.) Morgan; or in Thai), which has seasonal availability and a high market price. In order to collect these fungi, local farmers use fire either to clear the forest floor to make it easier to find the mushroom or because fire is thought to stimulate the growth of this mushroom. The burning of agricultural fields and forested areas in Southeast Asia is a yearly event, mainly during the "burning season", January through March. It is particularly widespread in the northern and northeastern provinces of Thailand. Northern Thailand has the highest rates of lung cancer in the country. The incidence of other chest diseases and cardiac conditions is also high. According to the
Bangkok Post, corporations in the agricultural sector, not farmers, are the biggest contributors to smoke pollution. The main source of the fires is forested area being cleared to make room for new crops. The new crops to be planted after the smoke clears are not rice and vegetables to feed locals. A single crop is responsible:
maize. The haze problem began in 2007 and has been traced at the local level and at the macro-market level to the growth of the animal feed business. "The true source of the haze ... sits in the boardrooms of corporations eager to expand production and profits. A chart of Thailand's growth in world corn markets can be overlaid on a chart of the number of fires. It is no longer acceptable to scapegoat hill tribes and slash-and-burn agriculture for the severe health and economic damage caused by this annual pollution." These data have been ignored by the government. The end is not in sight, as the number of fires has increased every year for a decade, and data show more pollution in late-February 2016 than in late-February 2015.
Charoen Pokphand (CP) Group, Thailand's largest agro-industrial and food conglomerate, and the leading purchaser of northern maize, in March 2016 announced an "agricultural social enterprise" to steer
Nan Province's
Pua District villagers away from maize farming. CP Group has incurred criticism for the way it purchases maize harvests for animal feed from farmers in Nan and other provinces.
Suphachai Chearavanont, vice-chairman of CP Group, said that corn planters will be encouraged to grow cash crops such as coffee, which requires less farmland and makes a higher profit than maize. Not only will this address deforestation, he said, but it will also help reduce the spring haze in the north which is caused by slash-and-burn practices to prepare land for the next maize season. Chearavanont said crops like coffee take about 3½ years to show a yield, but stated that CP Group would stand by farmers and provide assistance in the meantime. The Thai government has encouraged farmers to abandon rice farming and cultivate sugarcane instead. As a consequence, fields planted in sugarcane have soared from 6.8 million
rai in harvest year 2008–2009 to 11.5 million rai in 2017–2018. Sugarcane fields are a major locus of open fires. Despite anti-burning regulations, 66% of the sugarcane that entering processing mills in 2019 had been burned prior to harvesting. "Cheap and fast" is a shorthand explanation for the intentional use of fire to clear overgrown roadsides and open areas. Cattle herders also burn areas to stimulate the growth of
Imperata grass which is able to quickly produce new leaves during the hot-dry season. New leaves produced on burnt areas have a higher nutrient value, which is perfect for cattle grazing. Roadside fires are set to clear vegetation from encroaching on roadways. Fires produce large amounts of smoke which stagnates low lying areas, causing eye irritation and respiratory ailments. Large areas of degraded forest are destroyed by fire each year.{{cite journal |last1=Vaidhayakarn ==Fisheries==