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Risk topic
Air quality & wildfire smoke
What AQI and PM2.5 readings really mean, when to mask up, which destinations have a serious burning season — and how to get push alerts when air quality crashes.
TL;DR
- AQI > 100: unhealthy for sensitive groups. AQI > 150: unhealthy for everyone. AQI > 200: very unhealthy.
- PM2.5 is the fine particulate that drives most travel-relevant health risk.
- N95/KF94 masks block ~95% of PM2.5; surgical and cloth masks do not.
- HEPA-equipped hotels make a major difference during smoke events.
- TravelAlert surfaces IQAir, WHO and GDACS air-quality and wildfire alerts for your destinations.
Wildfire smoke and seasonal air-quality crises now affect more travel destinations every year. Chiang Mai's burning season, California and Pacific Northwest wildfires, Greek and Turkish summer fires, and the Indonesian peatland fire seasons all push PM2.5 readings into 'hazardous' territory for weeks at a time.
Reading AQI and PM2.5
The US EPA AQI scale is the most widely used standard worldwide. PM2.5 (fine particulate under 2.5 microns) is the metric that matters most for travel health — it lodges deep in the lungs and bloodstream and is the main driver of smoke-related symptoms.
- 0–50 (Good): no precautions needed
- 51–100 (Moderate): unusually sensitive groups should limit prolonged outdoor exertion
- 101–150 (Unhealthy for sensitive groups): mask outdoors if asthmatic, pregnant, elderly or with cardiac history
- 151–200 (Unhealthy): everyone should reduce prolonged outdoor exertion; wear N95 outdoors
- 201–300 (Very unhealthy): avoid outdoor activity; stay in HEPA-filtered indoor spaces
- 301+ (Hazardous): avoid all outdoor exposure; reconsider travel timing
Destinations with serious burning seasons
Several major travel destinations have predictable annual air-quality crises. Plan around them — or build in flexibility:
- Chiang Mai & northern Thailand (Feb–Apr) — PM2.5 routinely 200–300 µg/m³
- Singapore, KL, Indonesia (Aug–Oct) — peatland fire haze
- Western US & Canada (Jul–Sep) — wildfire smoke can affect SF, LA, Seattle, Vancouver
- Greece, Turkey, southern France (Jun–Sep) — wildfire smoke and heat-haze
- Delhi & northern India (Oct–Jan) — crop-burning + winter inversion, AQI 300+
- Mexico City (Mar–May) — pre-monsoon ozone and PM peaks
What actually works (and what doesn't)
Effective: N95/KF94 masks correctly fitted; staying indoors in HEPA-filtered spaces; closing windows and running HVAC on recirculate; checking AQI before outdoor activity. Not effective: surgical masks, cloth masks, bandanas, drinking water 'to flush toxins'. Sensitive groups (children, pregnant, elderly, asthmatic, cardiac) should reconsider travel timing rather than rely on workarounds.
Official sources for this topic
No rumors — only verified agencies.
- IQAir AirVisual
Real-time global AQI map; the most widely used reference for travelers.
- WHO Air Quality Database
Health-based PM2.5 thresholds and country data.
- AirNow (US EPA)
US official AQI source; wildfire smoke maps.
- Copernicus Atmosphere Monitoring
European satellite-based smoke and air-quality modelling.
Agency names and trademarks are property of their respective owners. TravelAlert is not affiliated with, endorsed by, or sponsored by any of these organizations. We surface their publicly available data; we do not speak for them and do not guarantee accuracy, completeness, or timeliness.
Frequently asked questions
Is wildfire smoke actually dangerous for healthy travelers?
Short exposure (a few days) at AQI 150–200 causes irritation but few lasting effects in healthy adults. Sustained exposure above 150 raises cardiovascular and respiratory risk for everyone, not just sensitive groups.
What mask should I bring?
N95 or KF94. Pack at least 3 per person — they degrade with humidity and wear. Surgical and cloth masks do not block PM2.5.
Should I cancel a trip during burning season?
Sensitive groups (children, elderly, asthmatic, cardiac, pregnant) should reconsider Chiang Mai trips between mid-February and mid-April, and Delhi trips in November. For healthy adults, mid-trip mask use and HEPA-equipped hotels are usually sufficient.
How accurate is IQAir vs official government data?
IQAir aggregates both official sensors and a large network of consumer sensors. Government readings (US EPA AirNow, EEA in Europe) are more accurate at specific stations but sparser. For travel planning, IQAir's coverage is more useful.
Do air purifiers in hotel rooms really help?
Yes — HEPA-equipped rooms can drop indoor PM2.5 by 80%+ within an hour. Several Chiang Mai and Delhi hotels now market 'clean-air rooms' specifically; book ahead during peak season.
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Open TravelAlertLast updated: 4 June 2026.