What Is Air Quality Index? and What It Has to Do with Our Life?

We are going to kick off this article by answering the all-important question — what is AQI?

Air Quality Index, or AQI for short, is a numerical scale used to measure air quality. In other words, the AQI helps you to know the level of contamination of air in your immediate environment. From the numbers, you can tell whether the air in your area is clean or polluted and subsequently take appropriate measures to protect yourself and your family.

AQI is also the standard way of reporting air quality in many different countries, and it’s managed by the EPA (U.S. Environmental Protection Agency). The result is reported daily, and it gives the public an estimate of the level of air pollution.

A rise in AQI denotes an increasing level of air pollution, and this poses a serious risk to our health. The most common places you will find these reports are newspapers, websites, TV, and radio.

Air Quality Index and Pollutants

The EPA calculates the air quality index based on five major air pollutants. This includes ozone, nitrogen dioxide, particulate matter, carbon monoxide, and sulfur dioxide. Out of all these pollutants, it seems ozone and particulate matter are most harmful to us and the environment.

Let’s look at these pollutants individually:


Ozone is a colorless gas present in the air. It is normally formed in the upper atmosphere, where it acts as a screen for ultraviolet radiation. Bad ozone usually appears near the ground when polluted air is exposed to the sun and heat, especially during summer.

The majority of people who have ozone problems are those who do a lot of physical activities outdoor. This is because more ozone is taken in when breathing becomes deep and faster.

Particulate Matter

It is simply any small discrete mass of solid or liquid matter that remains individually dispersed in liquid or gas emissions.

Some may have particles that can be as small as 2.5 micrometers in diameters such as dust, soot, and smoke, while others may come coarse with particles up to 10 micrometers such as mold and pollen.

The smaller particles are usually the ones that have the most impact on your respiratory health as they are able to go deeper into the lungs leading to inflammation and difficulty in breathing.

Pollution by particulate matter is more commonly felt during winter and may be more pronounced in people with lung or heart disease problems.

Carbon Monoxide

This is another colorless gas that is emitted from incomplete combustion of carbon in fuels.

Common sources include gasoline-powered equipment, automobile exhausts, furnaces and chimneys, industrial processes, and so on. Carbon monoxide is a very poisonous gas that can reduce the amount of oxygen in the body. Apart from being colorless, it’s also odorless, which makes it very difficult to detect in homes.

Sulfur Dioxide

This is a colorless toxic gas often released in volcanoes and sometimes in industrial emissions. It is the main cause of acid rain.

Nitrogen Dioxide

Nitrogen is another poisonous gas, reddish-brown in color, and also present in some industrial emissions.

The amount of these pollutants in the air is taken daily by the EPA and interpreted as a number on a scale between 0 – 500. The scale itself is divided into different number ranges, each one is represented by a specific color.

How Does Air Quality Index Work?

As earlier indicated, the AQI is measured on a scaled between 0 – 500. For instance, when the AQI value is low (0 – 50), then it means the air quality is OK. Under this condition, air pollution poses no serious risk to human health.

On the other hand, a higher AQI value denotes a higher level of air pollution, which simply implies a greater health risk.

An AQI of 100 is the general standard set by the Environmental Protection Agency that is acceptable for public health, while anything above 300 is considered very dangerous.

In addition, as we mentioned earlier, a specific color is assigned a different number ranges to make it easier for the general public to know when the air quality is good or unhealthy.

The color grouping basically starts from green for AQI (0 – 50) and becomes a darker red shade as the number increases.

For better clarity, we will summarize all the AQI ranges, their color, and health implications.

Numerical Value Color Health Quality Meaning
0-50 Green Good Satisfactory; poses little to no risk
50-100 Yellow Moderate Acceptable. But there might be little concerns for people sensitive to air pollutants
101-150 Orange Unhealthy for Sensitive Groups Sensitive people may be adversely affected. But still safe for the general public
151-200 Red Unhealthy Not safe for everyone
201-250 Purple Very Unhealthy Very serious effect for the entire population

What Should You Do?

Many of the health problems we have today are direct results of the constant pollution of the air around us. These include cardiovascular diseases as well as respiratory conditions such as pneumonia, asthma, and allergies.

In order to ensure your well-being, it is important you try as much as possible to reduce your exposure to these pollutants, especially during days when the AQI level is high.

Below are some things you can do to protect yourself and your family.

Keep Track of the AQI in Your Area

To better protect yourself and your family, you should constantly keep yourself updated with the air pollution levels in your area. In other words, always be current with the AQI report for your area, and plan your day subsequently.

You don’t want to be out on a day the AQI level is very high, especially if you’re sensitive to air pollution. If you must exercise, then do it indoors.

Avoid High Traffic Areas

In addition to planning your day according to the AQI level, also try to reduce your exposure to these pollutants when you eventually go outside. Stay away from places with higher pollution levels, such as industrial and high traffic areas.

If you’re exercising, try not to go near those places. It is best to do your exercises or any other strenuous activities in the early morning hours, as ozone levels are usually low during this time.

Clean the Air in Your Home

Since you spend most of the time in your home, it’s extremely important to take appropriate steps to minimize the number of pollutants in the surrounding air.

These include eliminating all sources of smoke, minimizing (or avoiding) the use of certain chemicals, keeping your home well ventilated and so on. One of the recommended ways to purify the air in your home is to use an air purifier.

Do Your Part in Reducing Emissions

Do your part in making the world a safer place by reducing emissions. Consider using public buses or trains when you go out with your friends or family.

Even when you drive, drive at slow speed when you’re on freeways. This will not only make your car more efficient but also help in reducing global warming.

Don’t Skip Your Medications

If you or anyone in your home is having any issues with their respiratory health, make sure you see a doctor and adhere strictly to medications. Always be ready to act during emergencies. And keep the air as clean as possible.

To Wrap It Up

Hopefully, you now know what the air quality index is and its implications to our daily lives. Remember, prevention is better than cure.

So make sure you take the necessary steps to protect yourself and your family from overexposure to airborne pollutants. We hope you’ve found this article useful. Let us know if you are not clear about anything.