Air quality in Thailand

Air quality index (AQI) and PM2.5 air pollution in Thailand

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Real-time Thailand
Most polluted city ranking

#cityUS AQI
1The national flag of International Sam Phran, Nakhon Pathom


2The national flag of International Din Daeng, Bangkok


3The national flag of International Phaya Thai, Bangkok


4The national flag of International Taling Chan, Bangkok


5The national flag of International Wang Thonglang, Bangkok


6The national flag of International Mae Rim, Chiang Mai


7The national flag of International Sathon, Bangkok


8The national flag of International Ayutthaya, Phra Nakhon Si Ayutthaya


9The national flag of International Bang Phli, Samut Prakan


10The national flag of International Cha-am, Phetchaburi


(local time)



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Real-time Thailand
Cleanest city ranking

#cityUS AQI
1The national flag of International Wiang Nuea, Mae Hong Son


2The national flag of International Pai, Mae Hong Son


3The national flag of International Mae Hi, Mae Hong Son


4The national flag of International Hang Dong, Chiang Mai


5The national flag of International Ratchaburi, Ratchaburi


6The national flag of International Chiang Mai, Chiang Mai


7The national flag of International Chiang Rai, Chiang Rai


8The national flag of International Mae Sot, Tak


9The national flag of International Thanyaburi, Pathum Thani


10The national flag of International Uttaradit, Uttaradit


(local time)


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How polluted is Thailand?

The national flag of International

2023 Air quality average

Human face indicating AQI level


2023 average US AQI





2023 average PM2.5 concentration in Thailand: 4.7 times the WHO annual air quality guideline value

2023  Thailand cleanest city Ko Chang Tai , Trat


2023  Thailand most polluted city Phan , Chiang Rai


2023 aqi country ranking

How does Thailand rank globally in air pollution?


Which country had the worst air quality in 2023?

1The national flag of InternationalBangladesh169,356,251


2The national flag of InternationalPakistan231,402,117


3The national flag of InternationalIndia1,407,563,842


4The national flag of InternationalTajikistan9,750,064


5The national flag of InternationalBurkina Faso22,100,683


6The national flag of InternationalIraq43,533,592


7The national flag of InternationalUnited Arab Emirates9,365,145


8The national flag of InternationalNepal30,034,989


9The national flag of InternationalEgypt109,262,178


10The national flag of InternationalDemocratic Republic of the Congo95,894,118


36The national flag of InternationalThailand71,601,103




Is Thailand very polluted?

Thailand as a country can be counted as a place that has numerous polluted cities, some of which are famous for their levels of smoke and haze. Bangkok has always topped the list of polluted cities, and even Chiang Mai, once renowned and hailed as a cleaner and less densely populated version of Bangkok, has in recent years exploded in terms of the level of pollution, having overtaken Bangkok in 2019, with the readings of PM2.5 sitting at a yearly average of 32.3 μg/m3, as opposed to Bangkok’s 22.8 μg/m3. Amongst all its major cities, these increases in dangerous particles and chemicals in the air push the AQI rating up to potentially hazardous levels.

The citizens of Thailand are definitively aware of this, but everyday life continues to go on, cars continue to get people back and forth from work, all the while emitting tons of toxic smoke and fumes, with many older vehicles such as buses and trucks, a great number of which are in various states of disrepair, sharing the road that give out their fair share of pollution and toxic fumes. Despite measures having been put into place by the government to remove such offending vehicles from the road, the preventative measures are not often fully enforced and the polluting trucks and buses continue to drive around the country, spreading their insidious PM2.5 content wherever they go.

It is for reasons such as this that Thailand could be considered as very polluted. In 2019, Thailand was ranked as the 28th most polluted country out of the 98 countries ranked in IQAir’s 2019 World Air Quality Report, with a yearly PM2.5 rating of 24.3 μg/m3, putting it at a rating of moderate risk to health according to the US Air Quality Index. Whilst this is not particularly terrible when compared to the world’s biggest offenders, it is still 2 times over the WHO’s exposure recommendation of PM2.5 and other dangerous chemicals such as nitrogen dioxide (NO2) sulfur dioxide (SO2) and carbon monoxide (CO) to name a few.

Whilst going from ground level experiences in cities such as Bangkok, one might be able to say that the pollution is extremely palpable and can cause a number of instant effects that leave a more profound imprint on a person’s memory, as opposed to the hidden long-term effects that we tend to push under the rug and forget about. These instant effects can include sore throats, other respiratory ailments and headaches when caught in areas of heavy traffic and during rush hour, with mask usage being extremely prevalent amongst the population of Bangkok and other cities long before the arrival of the 2020 COVID era.

For the average citizen or tourist, they would hardly even need to look at an air quality index to be able to tell that the air that they are breathing is not clean, however when the numbers for 2019 statistics regarding PM2.5 are examined, you can see that the top two most polluted countries in the world, Bangladesh and Pakistan, have an average PM2.5 concentration more than double than that of Thailand’s, with Bangladesh averaging 83.3 μg/m3, and Pakistan following closely behind with an annual average PM2.5 concentration of 65.8 μg/m3.

This can give some perspective that whilst Thailand most certainly has pollution problems as well as cities that have high concentrations of haze, smog and other contaminants in the air, it does not have air quality that is an immediate danger, unless you belong to the demographic of people who suffer from respiratory issues.

Many improvements could be made, and are currently being implemented that will surely bring its rating down over the coming years, but for now it could just simply be known as a moderately polluted city, where individuals with sensitivity towards certain chemicals found in the common pollutants should take preventative measures to keep themselves safe, and perhaps even resorting to using apps such as AirVisual by IQAir, which show constantly updating statistics of the levels of pollution in certain areas, so that these individuals who are at risk can take the appropriate action when levels of PM2.5 are detected as being higher.

What are some problems that Thailand faces with its air quality?

To put it simply, the main offending factors involving Thailand (that are not entirely unique to this country but rather something that many countries around the world and in the regions share or suffer from) are the exhaust fumes from traffic, in particular older buses and trucks that still flood the roads countrywide and permeate the atmosphere with their polluting and heavily outdated engines. The amount of PM2.5 that can be emitted from these defunct or old vehicles is extremely pertinent, with areas surrounding highways often caked in thick black soot, which is a collection of these fine particle matters that have become so concentrated that they start to visually change their surroundings.

On to the next offending phenomena, construction work is another culprit. Building sites use heavy machinery that runs on fossil fuels, emitting their own heavy amount of pollution and smoke, and the materials used in construction can produce a variety of different fine particulate matter with many that have toxic effects on our health, as well as industrial runoff that can find its way into the ecosystem via waterways or numerous other means. This includes microplastics, and a myriad of the previously mentioned chemicals plus more, such as volatile organic compounds (this is also a byproduct of farming and food industries) otherwise known as VOC’s, as well as heavy metals such as lead and unburned hydrocarbons, which have the potential, on a microscopic level, to bind to each other and other naturally occurring or man-made chemicals in the air or environment to cause even more dangerous pollutants to appear and enter into the biosphere of the country.

Since Thailand is still experiencing considerable annual growth, this sector may continue to press the AQI numbers up, as the ever increasing need for more construction of housing, condominiums, shopping malls and other urban areas of interest shows no sign of slowing down, which in turn go on to produce their own forms of pollution and PM2.5, as well as providing an artificial shelter of sorts whereby the trapped pollution within the concrete jungle of a city has nowhere to go, coalescing within and above the area. As such, the domino effect of this urban expansion often causes the growing city to eat into forested or areas of nature surrounding it, compounding the situation.

Crop burning in rural areas, as well as the fires from other regions in southeast Asia, contribute heavily to the particles found floating in the air, super fine burnt carbon from organic matter can become part of the PM2.5 collective, with the super fine particles easily finding its way into people’s lungs, and blood stream due to their small size, as well as ending up in the PM10 category as well, less serious due to its larger size but still with the potential to cause numerous health problems.

Lastly, factories and the industrial sector also contribute heavily to the levels of PM2.5, smoke and overall pollution. Thailand produces a huge amount of goods for the region of south east Asia, particularly food and household products. The processes involved in this industry produce a large amount of its own pollution, with the chemicals involved in the creation of plastics and other storage items being released into the atmosphere in microscopic forms, the factories themselves giving off large amounts of smoke and pushing PM2.5 into the atmosphere, and with this great demand comes the result that ever more pollution will be produced by the industry. The production of food on a large scale also pushes up the increase in farming demands, causing the opening of even more factories and fast production farms, furthermore all of this requires transport which leaves its own impact on overall levels of pollution. So, Thailand is so polluted because of a number of reasons related to the topical ‘urban diseases’ such as overcrowding and population boom, industry sector growth as well as less stringent rules being placed on companies or individuals that produce large amounts of noxious emissions.

What is Thailand doing about air pollution?

In recent years the particularly bad air quality of Bangkok as well as its other cities, has sent the government shuffling quickly to come up with some fast solutions to help ease the issue, as well as looking at long term goals that can be implemented to lessen the environmental crisis that their country and many major cities are undergoing.

It is important to note that Bangkok, typically known as one of the more polluted cities in Thailand, actually ranked in at number 48 out of 50 cities in Thailand, putting it at the lower end of the AQI spectrum, something that may come as a surprise to many, with its huge pollution and high concentrations of smoke and haze being something that residents and visitors alike have to stay concerned about.

In the minds of the Thai populous, the country may have somewhat of an innate structural inability to clean the quality of its air, with many of its root problems compounded by multifaceted issues that will take potentially years to reverse, let alone improve upon.

To give an example of why this is hard, in the beginning of 2019 another 180,000 vehicles were added and registered to the land transport department in Bangkok, and this was in the first two months alone. Local governments across Thailand are actively attempting to implement more stringent rules on the burning of materials outdoors, but even whilst these plans are being put into proposition (not action) another 320,000 hectares of corn crops came to life in the agricultural sector between late 2018 and early 2019. This is a large number that brings with it many more issues regarding the production of pollution, PM2.5 and further reduction in air quality, having visible effects on the registered AQI.

Regarding the automobile industry, attempts have been made to reduce the sulphur content put out by combustion in car and other vehicle engines, but the implementation of this was delayed by 13 years from its initial proposition date, and even by 2018 many oil refinery companies and supplies demanded a five year period of grace in which they can make the preparation for change, putting the date well past 2020 before such a change will happen.

On a more instantaneous but somewhat superficial level, when the levels of pollution and PM2.5 rise to particularly high levels, the government is known to implement measures such as the ‘seeding’ or creating artificial rainclouds in order to manifest a downpour to cleanse the air of fine particles, haze and other atmospheric smoke contaminants. Measures of reducing traffic, or at least the density of it in certain areas and certain times have also been implemented, along with the cleansing of roads with water via hoses in an attempt to drain away the thick accumulations of pollutions that line the underpasses and highways of Bangkok and other major cities. These implementations have had little impact, being transient or temporary at best and not addressing the root cause of the issue.

What is the most polluted city in Thailand?

According to the data obtained from the rankings on IQAir’s website, in regards to the level of PM2.5 in a particular region, the most polluted city in Thailand over 2019 was Nakhon Ratchasima.

The average PM2.5 rating in Nakhon Ratchasima during 2019 was 42.2 μg/m3, which is over double Bangkok’s 22.8 μg/m3. The first three months at the beginning of the year experienced the worst air quality, with January averaging 42.1 μg/m3, and then a huge spike in February to 67.9 μg/m3, and then 68 μg/m3 in March.

The months of February and March would be counted as being in the unhealthy air quality range, according to the US AQI ratings. The numbers drop substantially after this down to moderate levels (between 32 and 17 on the AQI rating) with data missing from August through to November. However, the recorded months alone stand to put it as the most polluted city in the whole of Thailand.

The reasons for this may have several causes behind them. It is one of the largest provinces in Thailand, located a few hours away from Bangkok by car. Nakhon Ratchasima, also known as Korat, are both interchangeable names of the city and province. The inhabitants are mainly engaged in the agricultural trades, so the number of farms and related industries are high. The burning of crops, as well as the pollution and smoke output from factories are contributing factors to the high levels of PM2.5. There are in excess of seven thousand industrial factories, and since the farming trade there mainly deals in rice, sugar cane and various fruits, the organic waste produced by these products as they make their way from farm to factory is of a considerably high volume.

Organic matter would be burnt as a result, releasing large amounts of smoke and pollution into the air, not to mention the other processes involved in any industrial sector, the chemicals used would contribute to the pollutive effect, and with high concentrations of industrial factories, it is only natural to expect a high level of pollution, especially when proper guidelines are not followed, or at least enforced by a governing body.

Nakhon Ratchasima has for a long time been well known as a gateway to the northern section of Thailand. Due to this positioning, it is inevitable that it will have a large number of cars, trucks and buses passing through it, thus contributing further to the pollution levels in the area. An increase in traffic generally means an increase in the consumption of fossil fuels, which in turn leads to a subsequent increase in smoke and other air contaminants entering the atmosphere.

These are all reasons that could contribute towards Nakhon Ratchasima being so highly ranked on the PM2.5 index and its unusually high spikes of pollution during certain months of the year. Nakhon Ratchasima is followed closely by the city of Saraphi air quality at an PM2.5 average of 41.3 μg/m3 during 2019, and then in third place the city of Pai air quality with an average of 38.9 μg/m3. There are eight Thai cities in total that are classed as being in the 'unhealthy for sensitive group' range of the US Air Quality Index, with the other 42 cities following behind in the moderate bracket. Getting a few cities into the ‘good’ range of annual AQI rating would certainly be an achievable goal within the next few years with a few small adjustments and changes.

Should you wear a mask in Thailand?

Based on the statistics of the 2019 readings of Thailand’s air quality index, on average the whole country has a yearly rating of being ‘moderately’ polluted. The PM2.5 concentration is two times above the WHO’s recommended guideline for annual PM2.5 exposure (10 μg/m3), coming in at a reading of 24.3 μg/m3. Those with respiratory issues or sensitivity to pollution or the other chemicals found in common city smoke (such as CO, SO2, NO2) should take precautions to wear a mask, particularly in certain areas or times of the day, or months of the year.

January through to May seem to be months with the highest concentrations of PM2.5, with the remaining months being less polluted until December when the pollution level begins to climb again, making mask wearing a good choice to go with.

This data can be found on the air quality map with active real time updates, as well as on the AirVisual app that can be accessed with ease on the go. Special high-quality air pollution masks are also available via the IQAir online shop, that provide a higher standard of protection to those that may need them.

Thailand air quality data attribution


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