Summary of WHO Air Quality Guidelines

Oct 24, 2024

WHO Global Air Quality Guidelines

Overview

  • Focused on air pollutants: Particulate matter (PM 2.5 and PM 10), ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide.
  • Published by World Health Organization (WHO) in 2021.
  • Available under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 IGO licence.
  • Aims to protect public health by reducing human exposure to harmful air pollutants.

Objectives

  • Provide evidence-informed guidelines for air quality management.
  • Offer quantitative recommendations for pollutant concentrations.
  • Serve as a tool for informing legislation and policy.
  • Provide interim targets for areas with high pollution levels.

Development Process

  • Followed a rigorous process involving WHO groups and external experts.
  • Involved systematic reviews and meta-analyses of scientific evidence.
  • Guidelines revised every few years based on new evidence.

Air Pollutants and Guidelines

Particulate Matter (PM 2.5 and PM 10)

  • PM 2.5: Annual guideline level of 5 µg/m³; 24-hour level of 15 µg/m³.
  • PM 10: Annual guideline level of 15 µg/m³; 24-hour level of 45 µg/m³.

Ozone

  • Peak season guideline level of 60 µg/m³ (average of daily maximum 8-hour mean).
  • Short-term guideline of 100 µg/m³ for daily maximum 8-hour average.

Nitrogen Dioxide (NO2)

  • Annual guideline level of 10 µg/m³.
  • Short-term (24-hour) guideline level of 25 µg/m³.

Sulfur Dioxide (SO2)

  • Short-term (24-hour) guideline of 40 µg/m³.

Carbon Monoxide (CO)

  • Short-term (24-hour) guideline of 4 mg/m³.

Good Practice Statements

Black Carbon and Elemental Carbon

  • Measure and reduce emissions.
  • Develop standards where appropriate.

Ultrafine Particles (UFP)

  • Quantify ambient UFP.
  • Integrate UFP monitoring into existing systems.
  • Define high and low particle number concentration (PNC) thresholds.

Sand and Dust Storms (SDS)

  • Implement air quality management and early warning systems.
  • Conduct research on health impacts and improve monitoring.
  • Promote regional cooperation to combat desertification.

Implementation and Monitoring

  • Guidelines serve as a reference for setting air quality standards globally.
  • Encourage capacity-building and cooperation among sectors.
  • Monitoring and evaluation to track guideline adoption and impact.

Future Research

  • Explore health impacts of low-level exposure and diverse pollutants.
  • Investigate multipollutant interactions and effects on vulnerable populations.
  • Develop improved methods for exposure assessment and intervention effectiveness.

Updates

  • Guidelines expected to remain valid for up to 10 years.
  • Continuous monitoring of scientific advances to inform future revisions.

Note: Interim targets provide incremental steps for pollution reduction and vary by pollutant and context.