What is the difference between the US AQI and WHO air quality guidelines? – IQAir

Comparison of U.S. Air Quality Index and WHO Air Quality Guidelines

Introduction

The U.S. Air Quality Index (AQI) and the World Health Organization (WHO) air quality guidelines serve the critical purpose of informing the public about health risks associated with air pollution. Both systems aim to protect public health, aligning with the Sustainable Development Goals (SDGs), particularly SDG 3 (Good Health and Well-being) and SDG 11 (Sustainable Cities and Communities). However, they differ significantly in their threshold values, especially concerning particulate matter (PM2.5).

Threshold Differences for PM2.5

1. U.S. AQI: Utilized by platforms such as AirNow and IQAir’s U.S. AQI⁺, which aggregates hourly data, categorizes PM2.5 concentrations below 9 μg/m³ as “Good”.
2. WHO 2021 Guidelines: Recommend an annual average PM2.5 concentration of 5 μg/m³ to minimize long-term health risks.

The WHO acknowledges that no level of air pollution is completely safe, establishing its guideline as the authoritative global benchmark for reducing exposure to PM2.5 over time. This distinction highlights the importance of continuous improvement in air quality to meet SDG targets.

Implications for Public Health and Sustainable Development

• While the U.S. AQI⁺ reflects real-time hourly concentrations, these levels may still exceed the WHO’s stricter annual guideline, underscoring the need for sustained air quality management.
• Both systems emphasize public health protection by providing essential guidance to reduce exposure to harmful air pollutants, supporting SDG 3 by aiming to reduce respiratory and cardiovascular diseases linked to air pollution.
• Improving air quality contributes to SDG 13 (Climate Action) by addressing pollution sources and promoting cleaner environments.

Visual Comparison of PM2.5 Concentrations

The following image illustrates the comparison between the U.S. AQI and WHO guidelines for PM2.5 concentrations, highlighting the significantly higher threshold for the “Good” category in the U.S. AQI system:

Additional Pollutants and Revised WHO Guidelines

For further reference, the chart below provides information on PM2.5, AQI, and additional pollutants as outlined in the revised WHO guideline, reinforcing the comprehensive approach needed to achieve SDG 3 and SDG 11:

Further Information

To understand how air quality data is gathered and the methodology behind the AQI, please refer to the following resource:

What is the air quality index (AQI)?

1. Sustainable Development Goals (SDGs) Addressed

1. SDG 3: Good Health and Well-being
   • The article discusses air quality and its impact on public health, specifically focusing on particulate matter (PM2.5) and its health risks.
2. SDG 11: Sustainable Cities and Communities
   • Air quality indices and guidelines are essential for creating healthier urban environments and sustainable communities.
3. SDG 13: Climate Action
   • Reducing air pollution contributes to climate action by mitigating pollutants that affect atmospheric conditions.

2. Specific Targets Under Those SDGs

1. SDG 3 – Target 3.9:
   • By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water, and soil pollution and contamination.
2. SDG 11 – Target 11.6:
   • By 2030, reduce the adverse per capita environmental impact of cities, including air quality improvements.
3. SDG 13 – Target 13.2:
   • Integrate climate change measures into national policies, strategies, and planning, which includes managing air pollution.

3. Indicators Mentioned or Implied in the Article

1. Indicator for SDG 3.9:
   • Concentration of fine particulate matter (PM2.5) in the air (measured in μg/m³), as indicated by both the U.S. Air Quality Index (AQI) and WHO air quality guidelines.
   • Annual average PM2.5 concentration, with WHO recommending 5 μg/m³ as a threshold to minimize long-term health risks.
2. Indicator for SDG 11.6:
   • Air Quality Index (AQI) levels, specifically the categorization of PM2.5 concentrations into “Good” or other categories based on thresholds.
3. Indicator for SDG 13.2:
   • Monitoring and reporting of hourly and annual PM2.5 concentrations to inform climate and environmental policies.

4. Table of SDGs, Targets, and Indicators

Source: iqair.com