|1||Pai, Mae Hong Son|
|2||Ban Bang Kadi Pathum Thani, Phra Nakhon Si Ayutthaya|
|3||乌汶叻差他尼, Changwat Ubon Ratchathani|
|4||Nam Phong, Khon Kaen|
|5||Si Chiang Mai, Nong Khai|
|6||Lop Buri, Lop Buri|
|7||Suphan Buri, Suphan Buri|
|8||Bang Pa-in, Phra Nakhon Si Ayutthaya|
|9||北欖坡, Nakhon Sawan|
|星期三, 4月 14|
不健康 170 美国 AQI
|星期四, 4月 15|
不健康 178 美国 AQI
|星期五, 4月 16|
非常不健康 255 美国 AQI
非常不健康 218 美国 AQI
|星期日, 4月 18|
中等 97 美国 AQI
|星期一, 4月 19|
中等 89 美国 AQI
|星期二, 4月 20|
中等 88 美国 AQI
|星期三, 4月 21|
对敏感人群不健康 108 美国 AQI
|星期四, 4月 22|
对敏感人群不健康 109 美国 AQI
|星期五, 4月 23|
对敏感人群不健康 113 美国 AQI
Pai is a small city located in the northernmost region of Thailand, part of the Mae Hong Son province and directly adjacent to the Myanmar border. It is well known as a popular tourist destination, with a very small population of some 2,284 people living there as of 2006, with no other recent census data available. In regards to the quality of its air, Pai suffers from some particularly bad pollution, which is unusual for a town with so few people as well as having a high altitude and being surrounded on all sides by heavy forest.
High altitude and large amounts of greenery often go a long way in reducing pollution levels, so for Pai’s readings to be so elevated shows there is a cause for concern. In 2019, Pai came in with a PM2.5 reading of 38.9 μg/m³, which puts it into the ‘unhealthy for sensitive groups’ bracket, a rating that requires a PM2.5 number anywhere between 35.5 to 55.4 μg/m³ to be classed as such.
With a yearly average this high, it means that Pai indeed suffers from above average levels of pollution, to the extent that it could cause harm to sensitive demographics such as young children, those with respiratory problems as well as pregnant mothers. This reading of 38.9 μg/m³ put it in 3rd place out of all cities ranked in Thailand in 2019, as well as 250th place out of all cities ranked worldwide, a very high rating with all factors considered.
Due to being a popular tourist destination, there would be a larger number of vehicles on the road catering specifically to tourists. These would include motorbikes and buses, as well as cars, although not as dense in number as would be seen in other more populous cities in Thailand such as Bangkok. Despite this though, a high concentration of these vehicles all squeezed into a tiny city can have a fairly significant effect on its ambient pollution levels year-round, especially with many of the vehicles running on unclean fuel sources such as diesel, a fossil fuel that gives off larger amounts of pollution that its cleaner alternatives.
The main cause of pollution in Pai however, is the problem of open burning sources. Farmers resort to the highly illegal practice of crop burning, as well as setting fire to forest areas to clear room for more farmland. These practices are usually practiced at the dead of night and in areas that are hard to reach, thus making enforcement a difficult task. It is such a large problem than many residents, particularly expatriates, will often flee from the northern region (including Chiang Mai) due to how bad these pollution levels can actually get.
Going off of the readings taken in 2019, one can see that there are a large number of discrepancies between the months of the year, with some coming in with super clean readings, and others coming in with highly elevated numbers. The months that stood out as being the worst were February, March and April, with PM2.5 readings of 65.3 μg/m³, 141.4 μg/m³ and 120.3 μg/m³ respectively, making March the most polluted month by a long shot.
This PM2.5 reading of 141.4 μg/m³ is somewhat disastrous, when compared to its cleanest month of July, which came in with a reading of 5.4 μg/m³. The differences are worlds apart, with 141.4 μg/m³ putting Pai into the higher end of the ‘unhealthy’ rating bracket, which requires a PM2.5 reading of anywhere between 55.5 to 150.4 μg/m³ to be classed as such. A few units higher than this would put it into the ‘very unhealthy’ bracket, meaning that the air would be extremely hazardous for anyone to breathe, as well as having adverse effects on the environment and wildlife.
Due to the large concentration of vehicles such as cars and motorbikes travelling in and out of Pai, slightly elevated levels of pollutants such as nitrogen dioxide (NO2) and sulfur dioxide (SO2) would be present in the air, although not in such a large quantity as major cities like Bangkok or Chiang Mai.
Other pollutants released from motor combustion would include materials such as black carbon and volatile organic compounds (VOC’s), both of which can be caused by the incomplete combustion of fossil fuels as well as organic materials. Thus, they both would arise as the result of vehicular use, as well as the aforementioned forest and farmland fires.
In regards to the pollutants released by the open burning practices, the smog and haze given out by these fires would be packed with chemicals such as benzene, carbon monoxide (CO), aldehydes, polynuclear aromatic hydrocarbons as well as the previously mentioned black carbon and VOC’s. In the month of March when the PM2.5 levels reached 141.4 μg/m³, these pollutants would be found in such high quantity that anyone inhaling the air during this time would be subject to a large variety of health problems, as well as an increased rate of them occurring.
Once again in regards to the months that showed the highest levels of PM2.5 (February through to April), a large number of health issues may arise. These would include ones primarily affecting the respiratory system as well as the circulatory and cardiovascular systems.
With exposure to large amounts of PM2.5 and PM10, irritation to the nose, throat eyes and skin can occur, triggering off allergies and reactions in those sensitive to chemical exposure. Incidences of lung cancer would also skyrocket, as the PM2.5 can make its way deep into the lung tissue and accumulate deep within the alveoli, causing a decrease in overall lung function as well as having the chance to cross the blood barrier and enter into the circulatory system. Once these toxic materials have found their way into the blood, damage to the blood vessels, kidneys, liver and reproductive system all become possible.
Expecting mothers who are overexposed to such levels of pollution may find themselves at risk of miscarriage, or giving birth prematurely to a baby that can suffer from both physical and cognitive defects. These are to name but a few of the negative health problems associated with breathing the air during the worst months of the year. Instances of such ailments occurring during cleaner months are reduced drastically, with preventative measures in keeping pollution exposure as low as possible during the worst months being of utmost importance.