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Vietnam · Tier 2
753 days · 2024–2026 · 5 sensors
Moderate confidenceSeasonal historical data — not for today's readings. For current air quality: IQAir ↗ · Methodology →
Independent modelled estimate for reference. Our data uses station sensors which may cover different years and locations. Methodology →
Berkeley Earth conversion: 22.0 µg/m³ PM2.5 ≈ 1 cigarette/day. This compares population-level mortality risk, not individual clinical outcomes. Acute vs chronic exposure differs significantly.
AQLI methodology: each 10 µg/m³ PM2.5 above WHO baseline (5.0 µg/m³) ≈ 0.98 years of life expectancy lost. Calculated from annual mean PM2.5 (long-term exposure), not annual median.
24-hour pattern from the most recent 7 days of hourly data. Dimmed arcs are unsafe for the selected activity.
This is a short-term trend view (not live minute-by-minute monitoring).
How does the air here compare to other health risks — and to peer cities?
Every day of the year, colored by PM2.5 air quality band.
The baseline view is No mask. You can switch to Surgical, KN95, or N95 to see a planning range for mask-adjusted exposure. Smoking-aware mode is optional and off by default.
Data-backed city context for Hanoi, with practical interpretation.
Coal power plants, motorcycles and brick kilns under northeast monsoon inversion
Affects: Nov, Dec, Jan, Feb
Agricultural burning transitions with monsoon onset
Affects: Mar
Southwest monsoon brings cleaner air from the Gulf of Tonkin
Affects: Jun, Jul, Aug, Sep
Hanoi residents lose an estimated 3.1 years of life expectancy on average due to PM2.5 air pollution — compared to living in a city that meets WHO air quality guidelines.
Each bar shows estimated life-years lost due to that risk factor. The orange bar is Hanoi. Gray bars are risk comparisons.
Source: AQLI methodology — each 10 µg/m³ above the WHO 5 µg/m³ baseline ≈ 0.98 life-years lost. Population-level statistical estimates, not individual predictions. Methodology →
Tip: tap a day cell to pin details, tap outside to close.
All-years view shows the median across available years per calendar day. Individual year views show actual measured values. Methodology →
Smoking-aware mode is optional. Turn it on only if you want combined smoking + air burden estimates.
Berkeley Earth conversion: 22 µg/m³ PM2.5 ≈ 1 cigarette/day. Statistical communication tool — not a clinical diagnosis.
Planning estimate from monthly median PM2.5 values. Air-equivalent burden is additive and does not replace smoking burden.
Based on monthly median PM2.5 values. Actual exposure varies by fit, wear time, location, activity, and daily conditions. Methodology →
Hanoi sits in the Red River Delta basin, where the northeast monsoon funnels winter pollution directly into the city. The annual median PM2.5 of 29.6 µg/m³ equates to 3.09 years of life expectancy lost—three times the impact of one cigarette per day by AQLI methodology.
The winter pollution season (November–February) is the critical period. Northeast monsoon winds transport combustion products from coal power stations, Hanoi's millions of motorcycles, and brick kilns operating at peak capacity during the dry season. Temperature inversions trap this mix in the basin. January median: 60 µg/m³, with over half of January days reaching Unhealthy levels and outdoor exercise inadvisable.
The summer monsoon (June–September) brings genuine relief. Southwest monsoon air from the Gulf of Tonkin carries cleaner maritime air and rain that washes particulates from the sky. June through August hover around 22–24 µg/m³—not clean by WHO standards, but the safest window the city offers. Cycling and outdoor activity are broadly feasible during this period.
October begins the deterioration. December median: 57 µg/m³, nearly matching January. If visiting for outdoor activity, June through early September is the clear choice. The city's motorcycle density ensures baseline pollution is elevated year-round; on bad winter days, an N95 mask is essential.
Data: OpenAQ API v3 · WHO 2021 AQI Guidelines · Berkeley Earth · Methodology →