Reading my data

Reading my data

The Plume AQI

The Plume AQI (Air Quality Index) gives you an immediate overview of what you are breathing, just as the temperature might give you a first indication of the weather outside.

What does the Plume AQI measure?

In order to easily communicate air pollution levels, governments and academics use an indicator referred to as an air quality index (AQI). The more polluted the air, the higher the number, the greater the share of the population that is likely to feel negative effects from pollution—be they short-term or long-term health impacts.

How is the Plume AQI calculated?

Plume Labs uses World Health Organisation (WHO) guidelines as well as international standards developed by the United States Environmental Protection Agency (EPA) and other scientific studies to define the Plume AQI and its seven associated categories.


The Plume AQI takes into account the concentrations of all different harmful pollutants your Flow is measuring and its overall value comes from the level of whichever pollutant is currently having the greatest impact on your health.

Pollution Thresholds

We base our recommendations on the WHO annual, daily, and hourly exposure guidelines, along with other global institutions, including the European Commission, the Chinese Air Quality Standards, and the United States EPA.


Each of the categories of the Plume AQI indicates something specific about the length of time that you can be exposed to such pollutant rates without an adverse impact on your health, so it ensures that you can get actionable information to take real steps towards improving your wellbeing.

0-20 Low Pollution

The air is clear—perfect for outdoor activities! Pollution levels are under the recommended exposure thresholds set by the World Health Organisation (WHO) for one year of pollution exposure. Nothing to worry about if your lights are green!

21-50 Moderate Pollution

Air quality is considered acceptable, though over the recommended WHO threshold for one year. This means that, unless you have these kinds of conditions all year round, you shouldn’t be experiencing adverse health effects. However, there may be certain health concerns for people with specific sensitivities. Always consult your physician!

51-100 High Pollution

The air is highly polluted—above twenty-four hour exposure recommendations from the World Health Organisation. Everyone may start to feel adverse health effects, and those with sensitivities should take care when performing outdoor activities.

101+ Very High Pollution and above

Everyone may start to experience more serious health effects at these levels, and long term exposure constitutes a real health risk. Levels have exceeded the recommended WHO exposure threshold for one hour.


In certain regions, or during exceptional pollution peaks, you may experience higher levels of pollution over 200 or even 300. These warnings constitute emergency conditions. There can be harmful impacts on the general public, even in the case of short-term exposure. All individuals should avoid physical activities until pollution subsides, regardless of sensitivities.

Understanding pollution

The air we breathe is made up of 99% oxygen and nitrogen but also of naturally occurring and human-induced pollutants, that may have a short or long-term impact on our health. Get an insight into the air pollutants covered by Flow!

Particulate Matter (PM10 and PM2.5)

What is it? These are small solid particles that can penetrate in the airways and lungs. The finest ones can even bind to blood vessels. PM10 (PM standing for particulate matter) refers to particles smaller than 10 microns in diameter and PM2.5 for those smaller than 2.5 microns.


Where do they come from? Human activities such as road traffic or energy transformation and from natural phenomenons such as volcanic eruptions. The PM concentration in the air significantly varies according to temperature and wind speed. They are particularly prevalent in cases of extreme cold and lack of wind, which prevents the particles from dispersing.


What are the risks? Fine particles cause many nasal allergies. Chronic exposure to fine particles is a risk factor for cardiovascular and respiratory diseases as well as lung cancer.

Nitrogen dioxide (NO2)

What is it? NO2 is a suffocating and irritating gas that can be easily recognized thanks to its red-brown color. It also has a pungent odor.


Where does it come from? Mainly from combustion (heating, electricity generation, vehicle and boat engines). 50% of NO2 emissions are due to traffic.


What are the risks? NO2 is responsible for bronchitis and asthma, especially for children. A high concentration of NO2 may also contribute to decreased lung function.

Volatile Organic Compounds (VOC)

What is it? These are molecules made mainly of carbon and found as gases in the air we breathe. They are very volatile and can spread a long way away from their emission source.


Where do they come from? VOCs are emitted by traffic, industries and the residential sector, and also by vegetation. Indoors, cleaning and DIY products are important emitters of VOCs, as well as some floor and wall coatings.


What are the risks? In cases of high concentration, they can cause irritation and decreased breathing capacity. Some VOCs are classified as carcinogenic.