Air Quality Index Calculator

The Air Quality Index (AQI) is an internationally recognized tool used to communicate how polluted the air currently is or how polluted it is forecast to become. Public health risks increase as the AQI rises.

Historical Background

The AQI was developed as a way to standardize the reporting of air quality across different countries. It simplifies complex air quality data, making it understandable and actionable for the general public.

Calculation Formula

The AQI is calculated using a linear segment of the AQI scale defined by two breakpoints:

\[ \text{AQI} = \left( \frac{\text{High AQI} - \text{Low AQI}}{\text{High Concentration} - \text{Low Concentration}} \right) \times (\text{Pollutant Concentration} - \text{Low Concentration}) + \text{Low AQI} \]

Where:

• High and Low AQI are the AQI values corresponding to the higher and lower concentration breakpoints.
• High and Low Concentration are the concentration breakpoints that encompass the pollutant concentration.

Example Calculation

Suppose the breakpoints for a particular pollutant are as follows:

• High AQI: 150
• Low AQI: 100
• High Concentration: 75 μg/m³
• Low Concentration: 50 μg/m³
• Pollutant Concentration: 60 μg/m³

\[ \text{AQI} = \left( \frac{150 - 100}{75 - 50} \right) \times (60 - 50) + 100 = 120 \]

So, the AQI for this pollutant concentration is 120.

Importance and Usage Scenarios

1. Public Health: Provides critical information about the air quality to the public.
2. Environmental Policy: Helps governments in making informed decisions about air quality regulations.
3. Urban Planning: Guides city planners in considering air quality in their designs.
4. Health Research: Assists researchers in studying the effects of air quality on health.

Common FAQs

1. What do the AQI numbers mean?

   • The AQI scale typically ranges from 0 to 500, where higher values indicate worse air quality and increased health risks.

2. Can the AQI be used for indoor air quality?

   • While primarily used for outdoor air, similar principles can be applied to indoor environments.

3. How often does the AQI change?

   • It can change throughout the day as the concentration of pollutants in the air varies.