Air quality comparison is the process of evaluating and comparing air quality metrics between different geographical locations. The Air Quality Index (AQI) is a standardized measurement system that quantifies air pollution levels and their potential health impacts. AQI values range from 0 to 500+, with higher values indicating worse air quality. This tool allows you to compare real-time air quality data from two different locations, including detailed pollutant measurements such as PM2.5 (fine particulate matter), PM10 (coarse particulate matter), O₃ (ozone), NO₂ (nitrogen dioxide), SO₂ (sulfur dioxide), and CO (carbon monoxide).
Air quality comparison tools are valuable for a wide range of users:
Comparing air quality between locations provides numerous benefits:
Our air quality comparator uses real-time data from the World Air Quality Index (WAQI) API:
The Air Quality Index (AQI) is a standardized scale from 0 to 500+ that indicates how polluted the air is. AQI values are calculated based on measurements of major air pollutants: PM2.5, PM10, O₃, NO₂, SO₂, and CO. Each pollutant has its own sub-index, and the highest sub-index becomes the overall AQI. The scale is color-coded: 0-50 (Good, green), 51-100 (Moderate, yellow), 101-150 (Unhealthy for Sensitive Groups, orange), 151-200 (Unhealthy, red), 201-300 (Very Unhealthy, purple), and 300+ (Hazardous, maroon).
PM2.5 refers to fine particulate matter with a diameter of 2.5 micrometers or smaller. These tiny particles can penetrate deep into the lungs and even enter the bloodstream, causing serious health problems. PM2.5 is considered one of the most harmful air pollutants because of its small size and ability to carry toxic substances. Sources include vehicle emissions, industrial processes, and wildfires. Long-term exposure to high PM2.5 levels is linked to respiratory diseases, heart problems, and premature death.
Air quality data is updated in real-time from monitoring stations worldwide. Update frequency varies by station, but most stations report new measurements hourly or more frequently. The tool displays the last update timestamp for each location so you can see how current the data is. Some stations may have slight delays, but the data typically reflects conditions within the past hour.
If your city doesn't appear in search results, it may not have an active air quality monitoring station in the WAQI network. The tool only shows locations where monitoring stations are available. Try searching for:
Coverage is best in major urban areas, but the network is continuously expanding.
PM2.5 and PM10 are both particulate matter, but differ in size:
Both are harmful, but PM2.5 is generally considered more dangerous due to its ability to reach deeper into the body. PM10 levels are often higher than PM2.5 because they include larger particles from dust, construction, and road traffic.
While the AQI scale (0-500+) is standardized, different countries may use slightly different calculation methods or color-coding systems. The US EPA AQI, European Air Quality Index, and Chinese AQI all use similar scales but may weight pollutants differently. Our tool uses the World Air Quality Index (WAQI) standard, which provides consistent measurements across countries. The health categories and color codes are universal, making it easy to compare locations globally.
If air quality is unhealthy (AQI above 100), consider these precautions:
Currently, the tool allows comparison of two locations at a time. To compare multiple locations, you can:
This approach allows you to evaluate multiple destinations systematically.