HomeBlogThe most dangerous types of air pollution

The most dangerous types of air pollution

Due to its complexity, air pollution is not an easy problem to solve. Understanding the influence of particular pollutants on our health and environment is crucial to adopt appropriate protective measures and fight the problem with success. In our complex guide, you’ll get to know the specifics of each air pollutant and its sources. Find out which pollution is most dangerous.

What is the most dangerous pollution?

Aside from climate change, air pollution is one of the most urgent problems we’re facing as a society – and solving it requires broad research, planning, and cooperation. For now, we dispose of a lot of tools that enable measuring the levels of particular emissions. Airly’s air pollution sensor integrated with an interactive map is one of the examples.

What is the most dangerous pollution? To understand the impact of air pollution on our wellbeing and the state of the environment, it’s worth starting from scratch. Let’s take a look at the characteristics of the pollutants. We’ve put them in order, starting from the most to the least dangerous to human health.

Most dangerous air pollutant – particulate matter

This group of air pollutants refers to solid particles that appear as a result of mixing the droplets present in the air with soot, dust, and mineral elements. It can have a natural origin – for example, wildfires or volcanic eruptions. However, the majority of particulate matter emissions come from burning processes and have an anthropogenic background.

Within the category of particulate matter, we can distinguish three different types. Their differentiation is based on the diameter measured in micrometers – a unit that also serves for defining the size of blood cells and bacteria. That reflects their dangerous potential – some are small enough to get into our bloodstream and reach the organs directly.


PM1 are air pollutants with a diameter of 1 micrometer (micrometer = one-thousandth of a millimetre) or less. PM1 is very dangerous to human health. The vast majority of these particles are small enough to pass directly into the bloodstream and lead to cancer, cardiovascular disease, or dementia.

PM 2.5

PM2.5 are air pollutants with a diameter of 2.5 micrometers (micrometer = one-thousandth of a millimetre) or less. Fine dust fractions can enter the bloodstream, and prolonged exposure to high concentrations can have a significant impact on heart disease such as hypertension, heart attack, or even increase the risk of cancer, especially lung cancer.


PM10 are air pollutants with a diameter of 10 micrometers (micrometer = one-thousandth of a millimetre) or less. Dust with a diameter of less than 10 micrometers is absorbed in the upper respiratory system and bronchi. When it enters the lungs, it can cause coughing and difficulty with breathing. PM10 contributes to an increased risk of respiratory infections and the occurrence of exacerbations of allergic diseases such as asthma, hay fever, and conjunctivitis.

Toxic gases

Just as particulate matter, gases can contribute to smog and pose a danger to human health in the case of a long exposure. Some gases listed – like, for instance, NO – can have a beneficial influence on our bodies in smaller amounts. Others are toxic, even in small doses. The majority of these gases have an anthropogenic origin, coming from coal-burning, industrial emissions, and exhaust fumes.


NO2 is a toxic air pollutant gas whose main source is emissions from road transport. Nitrogen dioxide damages immune system cells in the lungs and causes increased susceptibility to respiratory infections. It can make asthmatics more sensitive to allergens.


CO is a highly toxic compound that results from the incomplete combustion of fossil fuels and biofuels. Long-term exposure to CO causes changes in the cardiovascular system.


SO₂ is one of the most widespread gases polluting the atmosphere, emitted by heating and industrial plants. High concentrations of SO2 negatively affect the respiratory system, damaging the epithelium of the airways (nose, throat, lungs) and causing their narrowing.


NO, or nitric oxide (III), is a colourless gas that behaves as a free radical. In the presence of oxygen, it is oxidized to nitrogen dioxide (NO2). Nitrogen dioxide NO2 damages immune cells in the lungs and causes increased susceptibility to respiratory infections.


O3 Ozone (O₃) is a highly toxic gas that is produced by photochemical reactions in the atmosphere, especially during spring and summer. Ozone attacks and damages the cells lining the respiratory system, causing swelling and inflammation, as well as coughing and pharyngitis. It impairs lung function, increases symptoms of bronchitis and emphysema, and promotes asthmatic attacks. It also reduces the resistance of the respiratory system to infections.

Conclusion on the most dangerous type of pollution

Airly’s air pollution sensors can detect the key pollution markers included on the lists above. We make sure the measurements are the most accurate by calibrating the devices and continuously verifying them. Within a short period, we’ve created a dense net of sensors that monitor the emission levels worldwide and provide the interactive pollution map with real-time data. Try it out to have a better consciousness of pollution levels in your area!

Recent Posts

More and more people in society realise how dangerous smog and air pollutants can be to health. That’s why they look for approachable solutions that […]

Although most of us know that it’s crucial to minimise our exposure to smog and harmful substances, very few people realise that there is a […]

It’s been known for a long time that smog and contaminants don’t bring any benefits to the health, to say the least. Is air pollution […]