Surat Thani has no heavy industry and no equivalent to the northern burning season — air quality here is generally good year-round. The main local sources are ordinary traffic and diesel exhaust from the ferries and longtail boats that connect the mainland to Koh Samui, Koh Phangan and Koh Tao, plus an occasional regional haze episode drifting in from Indonesia, typically August to October.
Surat Thani's economy runs on fisheries, rubber, palm oil and durian orchards rather than heavy manufacturing, and its main role for most visitors is as the mainland ferry gateway to Koh Samui, Koh Phangan and Koh Tao. Between the lack of industry and the region's long monsoon calendar, air quality here is generally good year-round — a genuine advantage over northern Thai cities. One dated, attributed reference point: IQAir data put the 2019 annual PM2.5 average at roughly 16.6 µg/m³, comfortably in the good-to-low-moderate range. The real local sources of what pollution does occur are ordinary traffic plus diesel exhaust from ferry and longtail-boat engines around the piers, and there's an occasional, inconsistent August–October transboundary haze risk from Indonesian peatland fires drifting north on the southwest wind. We deliberately don't invent precise current numbers here — check Air4Thai or IQAir directly for today's reading. For the wider picture, see the Surat Thani hub.
These are directional, typical bands, not measured monthly averages specific to Surat Thani. Always check a live AQI source for today's actual reading.
| Month | Typical AQI band | What's happening |
|---|---|---|
| January | Good | Cool, dry season; clean air typical |
| February | Good | Dry season continues |
| March | Good | Warm and mostly dry |
| April | Good | Hot season; occasional haze possible but not the norm |
| May | Good → Moderate | Southwest monsoon builds; rain helps ventilate the air |
| June | Good | Monsoon rains; clean, well-ventilated air |
| July | Good | Monsoon continues |
| August | Good → Moderate (watch) | Start of the window when transboundary haze from Indonesian peatland fires can occasionally reach southern Thailand |
| September | Good → Moderate (watch) | Peak window for any regional haze episode, in years when the fires are severe |
| October | Good → Moderate (watch) | Haze risk tapers as the monsoon shifts |
| November | Good → Moderate | Northeast monsoon begins; heavy rain and flood risk becomes the bigger seasonal concern |
| December | Good | Wettest part of the northeast monsoon on this coast; flooding, not air quality, is the main weather risk |
US AQI reference: 0–50 good · 51–100 moderate · 101–150 unhealthy for sensitive groups. Surat Thani rarely goes beyond moderate.
Surat Thani doesn't carry the two big pollution drivers that hit other Thai cities hard: it has no significant heavy industry, and its province doesn't practice large-scale crop-residue burning the way northern and northeastern Thailand do. What local pollution exists is dominated by ordinary vehicle traffic and, distinctively for a transit-gateway city, diesel exhaust from the ferries and longtail boats that shuttle passengers and goods between the mainland and Don Sak pier out to Koh Samui, Koh Phangan and Koh Tao — those engines are often older and less efficient, and contribute a real if modest share of PM2.5 and PM10 around the busiest pier areas. It's a genuinely different pollution profile from an industrial or agricultural-burning city: more a function of Surat Thani's role as a busy transport hub than of manufacturing or farming.
Southern Thailand's one recurring outside risk is transboundary haze from large-scale peatland and forest fires in Indonesia, mainly during that region's own dry season. Smoke can drift north on the southwest monsoon wind and affect southern Thailand in the worst years, roughly within an August to October window — the same broader phenomenon that periodically blankets Malaysia and Singapore. Surat Thani is generally less affected than areas further south or closer to Sumatra, and the risk is inconsistent year to year rather than an annual certainty: some years pass with barely a noticeable effect. It's worth a quick check on an aggregator app during that window if you're planning outdoor time or an island crossing.
Thailand's Pollution Control Department (PCD) runs the national monitoring network, reported through Air4Thai:
The official app and website from Thailand's Pollution Control Department (PCD) — the authoritative source for a current reading anywhere in Thailand, including a monitoring station covering the Surat Thani area.
A widely used app blending official and independent-sensor data with live AQI, PM2.5 and short forecasts — a quick way to check conditions before a ferry crossing to Koh Samui, Koh Phangan or Koh Tao.
A free web map aggregating stations across Thailand, useful during the Aug–Oct window for tracking whether a reported regional haze episode is actually reaching the Surat Thani area.
Primary and official sources are cited above. Government rules, fees and procedures in Thailand change over time and vary by office; always confirm current requirements with the relevant authority before relying on them. BAANLYY never takes paid placement in editorial content.
Not really. Surat Thani is a mainland Gulf-coast provincial capital with no heavy industry — its economy runs on fisheries, rubber, palm oil and durian orchards rather than manufacturing — and its main function for most visitors is as the transit gateway to Koh Samui, Koh Phangan and Koh Tao. Air quality is generally good year-round, and there is no equivalent of the severe agricultural burning season that affects Chiang Mai or the northeast.
Local pollution here is mostly ordinary traffic exhaust plus diesel emissions from the boats that run tourists and goods to and from the islands — ferry and longtail-boat engines are frequently older and less efficient, and contribute a meaningful share of local PM2.5 and PM10 around the piers and town. It's a different profile from northern Thailand's crop-burning-driven haze: more a function of Surat Thani's role as a busy transport gateway than of industry or agriculture.
Occasionally, and usually less severely than areas further south or closer to Sumatra. Large-scale peatland and forest fires in Indonesia, mainly during that region's own dry season, can send haze drifting into southern Thailand on the southwest wind, typically within a broad August–October window. It doesn't happen with the same severity every year — some years pass largely unaffected, while others (usually El Niño-driven) bring a more noticeable regional haze episode.
We deliberately avoid inventing precise daily or monthly figures here, since conditions vary year to year. One dated, attributed historical reference point: IQAir data put Surat Thani's 2019 annual PM2.5 average at roughly 16.6 micrograms per cubic metre, at the lower end of the 'moderate' US AQI band — a genuinely good reading by Thai standards. For a current number, check Air4Thai or IQAir directly rather than relying on any static figure, including this one.
Not typically for health reasons — but it's worth knowing that diesel exhaust from ferry and longtail-boat engines is one of the more noticeable local sources of air pollution around the piers, more a nuisance than a genuine health concern for most travelers. If you have a respiratory sensitivity, it's a minor factor to be aware of at busy pier areas like Don Sak, though nothing on the scale of a genuine burning-season city.
Seasonal monsoon rain and flood risk during the November–December northeast monsoon is a more practical everyday concern here than air quality, along with checking sea conditions before an island ferry crossing in that same window. Most residents don't think about air quality day to day the way they would in Chiang Mai or Bangkok.
Good year-round air is one of Surat Thani's quieter advantages — find the right base for your mainland-to-island lifestyle.
Hero photo by Laura Meinhardt on Pexels.