Air Quality index

Search Location

Enter a city name, postal code, or zip code to check air quality

Search for a location or use your current location to check air quality

What is the Air Quality Index (AQI)?

The Air Quality Index (AQI) serves as a global numerical scale that indicates how clean or polluted the air is in a particular area on any given day. By converting complex air pollution data into an easy-to-understand single number and colour, it helps people grasp the health implications related to the air they breathe.

Generally, a higher AQI number indicates increased pollution levels and associated health risks. For instance, an AQI of 50 signifies good air quality, while an AQI of 300 falls into the hazardous category.

How Does AQI Work & Why Should You Care?

The AQI monitors the concentrations of significant air pollutants, including:
– Particulate Matter (PM2.5 and PM10)
– Ground-level Ozone (O₃)
– Nitrogen Dioxide (NO₂)
– Sulfur Dioxide (SO₂)
– Carbon Monoxide (CO)

Each pollutant is assigned an AQI value, and the highest value recorded on that day determines the official AQI. It’s also important to note that the AQI is divided into six categories, each associated with a unique colour and specific health warning, helping you understand what to expect and how to protect your health.

AQI Range	Color	Air Quality	Health Concern
0–50	Green	Good	No risk
51–100	Yellow	Moderate	Little risk, sensitive groups may notice effects
101–150	Orange	Unhealthy for Sensitive Groups	Sensitive groups may be at risk
151–200	Red	Unhealthy	Everyone may be at risk
201–300	Purple	Very Unhealthy	Health alert for everyone
301+	Maroon	Hazardous	Health warning emergency

Why Is the AQI Important for Health?

Understanding AQI numbers is crucial because air pollution can lead to various health issues, including:

– Breathing difficulties and asthma flare-ups
– A heightened risk of heart and lung diseases
– Deteriorating health conditions for children, the elderly, and individuals with pre-existing health issues
– A reduced life expectancy in regions with consistently poor air quality

Even if you consider yourself healthy, extremely high AQI days can impact how you feel. They may limit your opportunities to enjoy outdoor activities.

1. What countries have the worst and best AQI right now?
In 2025, the most polluted areas include India (average AQI: 155), alongside Senegal, Italy, Nepal, and DR Congo. Conversely, the cleanest regions are Thailand (average AQI: 14), Taiwan, and Norway.

2. How often should I check the AQI?
If you live in urban settings or are close to known pollution sources, it’s a good idea to check the AQI daily. Always check it before engaging in outdoor activities, particularly if you’re sensitive to air quality.

3. How do I protect myself when the AQI is bad?
Try to limit outdoor exercise, especially during times when the AQI is high. Keep your windows and doors shut, utilise air purifiers indoors, and consider wearing N95 masks if you need to go outside on hazardous days.

4. Can AQI be predicted?
Thankfully, many environmental and weather agencies now offer real-time updates and forecasts on AQI, which can help you plan your activities more effectively.

How Does AQI Affect Children, the Elderly, and People with Lung Issues?

Children’s lungs are still developing and are more sensitive to pollution.
Elderly and those with asthma, COPD, or heart issues feel the effects sooner and more severely.
On “orange” AQI days, sensitive groups should limit strenuous outdoor activity. On “red” days, everyone should take precautions.

What Can You Do to Improve Air Quality at Home?

Here are practical, low-cost ways you can boost your indoor air quality:

Open windows daily (unless outdoor AQI is high)
Use HEPA air purifiers
Keep your home and car smoke-free
Avoid burning wood, candles, or incense
Choose low-VOC (volatile organic compound) paints and cleaning products
Vacuum and dust often
Add air-purifying indoor plants (like peace lilies and spider plants)
Change furnace/AC filters regularly
Test your home for radon

Air Quality Index vs. Air Quality Health Index—Is There a Difference?

Some countries, like Canada, use the Air Quality Health Index (AQHI), which directly links numbers to health advice on a scale from 1 to 10+. Both AQI and AQHI help people understand air pollution in the context of personal health, but AQHI places a primary focus on health impact rather than only pollution concentrations.

What does 'PM2.5' mean in AQI?

PM2.5 is “particulate matter” smaller than 2.5 microns—a significant health risk because these particles go deep into your lungs.

Is it safe to exercise outside on a 'yellow' AQI day?

Yes, for most people, but those who are sensitive to pollution (asthma, elderly) may want to exercise caution.

Which apps or websites give reliable AQI data?

Try official government platforms, international sites like IQAir, World’s Air Pollution AQI, and your country’s meteorology department.

Can poor AQI cause permanent lung damage?

Long-term exposure, especially to high AQI levels, can cause lung and heart diseases, reduce lung growth in kids, and shorten lifespan.