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WHO tightened global air quality guidelines, cutting annual PM2.5 target to 5 µg/m³

Dated 22 September 2021: WHO tightened global air quality guidelines, cutting annual PM2.5 target to 5 µg/m³. In the causal graph this event strengthens Air Pollution, a driver that strengthens Exposed to air pollution — a worsening welfare path.

Who was responsible

Contribution type and responsibility level for each recorded actor — not sole-author shorthand.

No public contributors are listed for this fact.

What changed

Fact → Driver → Indicator. Relationship strength orders the paths; it is not the observed indicator movement.

    1. FactWHO tightened global air quality guidelines, cutting annual PM2.5 target to 5 µg/m³
    2. strengthensDriverAir Pollution
    3. strengthensIndicators (2)Exposed to air pollution
    Worsening path

    provisional weight · verified

    • Exposed to air pollution

      via Air Pollution

      Worse

      Strengthens · 88% impact strength (driver → indicator)

      Observed

      95.9% of population · 3.28 below the normal line (2020)

      Better than normal

      3 readings, 2018–2020: fell from 97.6% of population to 95.9% of population.

      Above normal = worse

    • Age-standardised mortality rate from diseases of the circulatory system

      via Air Pollution

      Worse

      Strengthens · 76% impact strength (driver → indicator)

      Observed

      403 deaths per 100,000 population · 164 above the normal line (2023)

      Worse than normal

      6 readings, 2018–2023: fell from 435 deaths per 100,000 population to 403 deaths per 100,000 population.

      Above normal = worse

Causal path

How this event connects to drivers and indicators in the graph.

  1. FactWHO tightened global air quality guidelines, cutting annual PM2.5 target to 5 µg/m³
  2. strengthensDriverAir Pollution
  3. strengthensIndicatorExposed to air pollution

Cite this page

Factrail. (2026). WHO tightened global air quality guidelines, cutting annual PM2.5 target to 5 µg/m³. Factrail. https://factrail.ai/facts/who-global-air-quality-guidelines-2021

https://factrail.ai/facts/who-global-air-quality-guidelines-2021

Accessed 16 October 2026.

By the Factrail desk · Method: how we source and score · Last reviewed

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