Air Quality Index Hub

Overview

An Air Quality Index (AQI), also known as an Air Pollution Index (API) or Pollution Standard Index (PSI), is an indicator used to inform the public about air quality. An AQI is a unitless value, often accompanied by a color and categorical label, summarizing the concentration of a single pollutant or multiple pollutants on a standardized scale. AQIs help communities understand the potential health impacts of current air quality conditions and take necessary precautions. By translating complex pollutant concentration data into a simple, understandable format, AQIs can empower individuals to make informed decisions about how to protect their health, such as curbing outdoor activities.

AQIs are shaped by public health considerations, atmospheric chemistry, and political factors. Consequently, countries and other regulatory bodies develop their own AQIs to reflect their particular air quality standards and health guidelines.

What is the AQI Hub?

The AQI Hub is a comprehensive online resource dedicated to deepening the public’s understanding of their own AQI and AQIs worldwide. The AQI Hub provides detailed descriptions of various national and regional AQI systems, enabling users to understand how an AQI is built and to compare and contrast how different countries assess and communicate air quality. By exploring the methodologies, scales, and health implications associated with each AQI, the AQI Hub empowers individuals to better interpret air quality data, fostering informed decisions about health and environmental protection.

Many people do not know how AQIs are calculated and do not realize that they vary significantly. This can lead to misunderstandings about the risks posed by air pollution and difficulty in comparing AQIs across regions. By “decoding” the opaque nature of AQIs and centralizing fragmented information, the AQI Hub provides clarity and transparency. People can better assess their exposure to air pollution and take appropriate actions to safeguard their health and well-being.

The chart below shows how AQIs representing a 24-hour average concentration for PM2.5 vary greatly across nations, demonstrating the importance of understanding each country’s methodology:

Belgium China Colombia Costa Rica European Union India Indonesia Ireland Israel Kuwait Macao Mexico Mongolia Peru Philippines Ecuador Singapore South Korea Sri Lanka Taiwan Thailand United Kingdom United States of America Vietnam 0 50 100 150 200 250 300 350 400 450 500 National AQI PM2.5 24 hr. avg. µg/m³ →

Note: Adapted from “Why we should have a universal air quality index?” (2024), https://doi.org/10.1016/j.envint.2024.108698. Accessed 5 Aug. 2024.

Who built the AQI Hub?

OpenAQ, a nonprofit non-governmental organization, built the AQI Hub. OpenAQ is the world’s first and largest open-source, open-access database of real-time and historical outdoor air quality measurements. OpenAQ harmonizes the data for easy comparison and shares the data in physical units rather than as an air quality index. OpenAQ serves as a resource for air quality analysis, communications, advocacy and more, enabling countless applications and initiatives. Data on OpenAQ are accessible via an API or via OpenAQ Explorer, a map-based interface showing real-time data and related visualizations.

References

Ravindra, Khaiwal et al. “Why we should have a universal air quality index?” Environment International, Vol. 187, May 2024, https://doi.org/10.1016/j.envint.2024.108698.

“How to Calculate AQI and NowCast Indices.” Met One Instruments, https://metone.com/how-to-calculate-aqi-and-nowcast-indices.