Question 1

When is Bangkok's air quality worst?

Accepted Answer

January through April is 'burning season' — agricultural burning across northern Thailand and the central plains combines with low winds and a temperature inversion to trap PM2.5 over Bangkok. Daily averages routinely hit 80–150 µg/m³ in February and March (vs the WHO 24-hour guideline of 15 µg/m³). May to October is much better — monsoon rains wash particulates out of the atmosphere and AQI is usually 'moderate' to 'good'.

Question 2

What is PM2.5 and why does it matter?

Accepted Answer

PM2.5 refers to particulate matter smaller than 2.5 micrometres — small enough to pass through the lungs into the bloodstream. Long-term exposure is linked to cardiovascular disease, lung cancer, stroke, and reduced life expectancy. Short-term exposure triggers headaches, sore throat, asthma flare-ups, and irritated eyes. Sensitive groups — children, elderly, asthmatics, pregnant women — feel effects at much lower thresholds than healthy adults.

Question 3

Which apps should I use to monitor Bangkok air quality?

Accepted Answer

IQAir AirVisual is the most-used app, pulling data from a dense network of community sensors plus the Thai government's monitoring stations. The 'air4thai.com' site (and matching app) is the Thai Pollution Control Department's official source. AirGradient's open dashboard is good for tracking individual neighbourhoods. Apple Weather and Google Weather both show a simplified AQI badge in Thailand. Cross-check IQAir against air4thai if a reading looks suspicious.

Question 4

Are N95 masks enough? What about cloth or surgical masks?

Accepted Answer

N95 (or KN95 / KF94) is the minimum standard for PM2.5 protection — they filter at least 95% of 0.3 µm particles when fitted properly. Surgical masks block droplets but only a fraction of PM2.5. Cloth masks are essentially useless against fine particulates. 7-Eleven, Watsons, Boots, and most pharmacies sell N95s for 25–80 THB each; reusable models like 3M Aura 9210, Airinum, or O2 Canada last weeks of daily wear. The fit matters more than the brand — gaps around the nose halve filtration.

Question 5

Do I need an air purifier in Bangkok?

Accepted Answer

Strongly recommended if you live in Bangkok or stay during burning season. Choose a unit with a true HEPA filter rated for the room size — typical Bangkok bedroom (12–20 m²) needs a Clean Air Delivery Rate (CADR) of at least 200 m³/h. Reliable brands: Xiaomi/Mi (best value, 4,000–8,000 THB), Philips, Dyson, IQAir HealthPro (top-tier, 30,000+ THB). Run continuously on auto mode during AQI events. Replace HEPA filters every 6–12 months in Bangkok — they clog faster than in cleaner cities.

Question 6

Should I cancel a trip during burning season?

Accepted Answer

Not unless you're in a high-risk group. AQI in central Bangkok is usually in the 100–180 range during burning season — uncomfortable and not great for long outdoor exertion, but tolerable for normal sightseeing with N95s and indoor breaks. Travellers with asthma, COPD, heart conditions, or young children should consider Phuket or Koh Samui instead (coastal southern Thailand stays clean year-round). Chiang Mai is dramatically worse than Bangkok in March–April and should be avoided entirely by sensitive groups during those months.

Question 7

What's the AQI scale and what should I do at each level?

Accepted Answer

0–50 Good: do anything outdoors. 51–100 Moderate: sensitive groups should limit prolonged outdoor exertion. 101–150 Unhealthy for sensitive groups: kids, elderly, asthmatics wear N95 outdoors, others fine. 151–200 Unhealthy: everyone should reduce outdoor time and wear N95; sensitive groups stay indoors. 201–300 Very unhealthy: avoid outdoor exercise entirely, indoor air purifier running. 300+ Hazardous: stay indoors, sealed windows, N95 even briefly outside. Bangkok rarely exceeds 200 in central districts; northern Thailand (Chiang Mai, Chiang Rai) routinely does in burning season.

Question 8

Will the air quality issue ever get better?

Accepted Answer

Slowly. The Thai government passed a Clean Air Act in 2024 with tighter agricultural burning controls and industrial emissions standards. Enforcement is inconsistent. The structural drivers — sugarcane burning, rice-stubble burning, vehicle emissions, regional transboundary pollution from neighbouring countries — won't disappear overnight. Bangkok's air has improved measurably since 2018 with stricter Euro 5/6 vehicle emissions and reduced industrial coal use, but burning-season spikes are likely to remain a feature of January–April for at least the next decade.

Bangkok Air Quality Guide

Why Bangkok's Air Quality Matters

AQI Levels — What to Do at Each

Monitoring Tools

IQAir AirVisual

air4thai.com (Thai Government)

AirGradient

Apple Weather / Google Weather

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Sources & official references

Frequently Asked Questions