La air quality in Greece It has become a central issue for those who live there, travel frequently to the country, or simply want to better understand what they are breathing in cities like Athens, Thessaloniki, or coastal areas. Although Greece is often associated with islands, beaches, and clear skies, the reality is that air pollution also plays a significant role in public health and in planning outdoor activities.
When we talk about air quality index in Greece We're referring to a standardized way of translating complex pollution data into a simple number, usually represented with colors, that anyone can interpret at a glance. This index draws on meteorological measurements and models, but it's important to know that not all the values we see on maps and in apps are validated in real time, and therefore there's always some margin of uncertainty.
What is the air quality index and how is it interpreted in Greece?
In much of Europe, the following has been used since 2006: Common Air Quality Index (CAQI)A numerical scale that ranges approximately from 1 to 100. The lower the value, the better the air quality; beyond certain thresholds, the color changes from green to yellow, orange, and red to indicate increasingly polluted and potentially harmful air.
This index is also used to characterize the air quality in Greek cities like Athens, where the combination of heavy traffic, mountainous terrain and episodes of Saharan dust It can cause pollution levels to spike on certain days. The colors associated with the CAQI are used in meteograms and pollution forecast maps, making it easy for anyone to quickly understand whether the air quality is good, moderate, or poor.
It is important to distinguish that the CAQI considers different situations: there is an index for air of urban or regional background (areas far from the edge of roads) and another for air next to roads with heavy traffic, which is called the "roadside" index. The weather models commonly used for forecasts, such as those integrated into specialized platforms, can only accurately represent the background index, because they do not capture the very small-scale variations that occur right next to a busy highway or avenue.
For this reason, direct measurements from stations located next to roads They often show higher pollution levels than those predicted by air quality models. This doesn't necessarily mean the forecast is wrong, but rather that it describes an average situation for the area and not the exact spot where hundreds or thousands of cars pass by every hour.
In Greece, as in the rest of Europe, the air quality index is used not only to inform the public but also to support public health decisions, pollution alerts, and recommendations. vulnerable groups, such as children, the elderly, or people with chronic respiratory illnesses.
Warnings and limitations of air quality data
All data related to air quality that we see in near real time Forecasts and other information have several limitations that should be kept in mind. In many cases, the information is published before it has undergone the full validation process of official agencies, so it may be subject to subsequent corrections without prior notice.
Projects like the World Air Quality Index European meteorological services use advanced numerical models and observation networks to generate this data. However, they make it clear in their legal notices that, although reasonable care has been taken in collecting and processing the information, they cannot accept contractual or extra-contractual liability for any loss, damage, or injury arising directly or indirectly from the use of this data.
Something similar happens with European organizations such as the European Commission or with prediction centers like ECMWF and platforms like meteoblue. They themselves point out that air pollution forecasts have a limited spatial resolution (for example, on the order of 12 km) and that the modeled values may not correlate in detail with the actual concentrations at street level, especially in places with very marked urban microclimates.
For this reason it is always recommended Consult official information from local air quality agencies from Greece, especially during pollution spikes, smog episodes, or public health alerts. Global models and maps are an excellent reference for identifying trends, but they do not replace the monitoring carried out by national or regional networks.
In summary, air quality data should be understood as a guidance and support tool: very useful for planning activities, comparing areas or anticipating pollution events, but it cannot be considered infallible or used as the sole source for critical health or emergency management decisions.
Particulate matter in the air in Greece: PM10, PM2.5 and desert dust
One of the key components of the air quality index in Greece is the suspended particles or particulate matter (PM)Particulate matter consists of tiny solid fragments or liquid droplets that float in the atmosphere. Their microscopic size allows them to be inhaled and reach deep into the respiratory system, with significant health impacts.
Among the most closely monitored factions are the PM10That is, particles with a diameter of less than 10 microns (about one-seventh the thickness of a human hair). These particles can be of natural origin—such as mineral dust, sea salt, or volcanic ash—or anthropogenic, originating from industrial processes, road traffic, biomass combustion, forest fires or construction.
PM10 is not a homogeneous pollutant, but a mixture of very diverse substances This can include soot, smoke, road dust, metal fragments, acids, salts, and other chemical compounds. In addition, some of these particles are formed secondarily when gases, such as those emitted by vehicles or industries, react in the atmosphere, generating aerosols that end up in the PM10 fraction.
In many cities, including large Greek cities, PM10 particles are visually manifested as a kind of brownish mist or fogThis is commonly known as smog. When PM10 levels are high, visibility can be reduced and the landscape appears duller, even on theoretically sunny days.
From a health perspective, PM10 particles are among the most harmful air pollutantsVarious studies have shown that they can increase the number and severity of asthma attacks, trigger or worsen bronchitis and other lung diseases, and decrease the body's ability to cope with respiratory infections.
Within PM10 there is an even finer fraction, the PM2.5These particles are made up of particles with a diameter of 2,5 microns or less. They are so small that they not only reach the deepest parts of the lungs, but can also enter the bloodstream, causing an even more serious long-term health impact.
Prolonged exposure to PM2.5 is associated with increased mortalityThis is especially true for older adults and those with cardiovascular conditions. Clear links have been observed with an increased risk of heart attack, ischemic heart disease, and the worsening of pre-existing respiratory illnesses. Therefore, PM2.5 levels have become a crucial indicator for assessing the actual dangers of air pollution.
In the case of Greece, there is an added factor: the desert dustAir masses originating from the Sahara carry mineral particles that can travel thousands of kilometers and reach the eastern Mediterranean. This dust is typically composed of particles smaller than 62 microns, and a significant portion falls within the PM10 and PM2.5 ranges, causing localized increases in pollution.
When intrusion incidents are recorded Saharan dust over GreeceParticulate matter levels spike, increasing the risks associated with exposure to PM10 and PM2.5. Sensitive individuals—especially those with asthma, COPD, or other respiratory conditions—may experience increased coughing, shortness of breath, or eye and throat irritation, making it advisable to reduce strenuous outdoor physical activity on these days.
Main polluting gases: ozone, sulfur dioxide, nitrogen dioxide and carbon monoxide
In addition to the particles, the The air quality index in Greece incorporates various polluting gases. These play a key role in health problems and in the formation of other secondary pollutants. Among the most relevant are tropospheric ozone (O₃), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and carbon monoxide (CO).
El ground-level ozone Tropospheric ozone should not be confused with stratospheric ozone, which protects us from ultraviolet radiation. Tropospheric ozone is generated in the lower atmosphere when pollutants such as nitrogen oxides (NOx) and volatile organic compounds (VOCs), emitted by vehicles and industries, react under the influence of sunlight. This gas is one of the main components of photochemical smog in urban environments.
Exposure to high concentrations of surface ozone It can make deep breathing difficult, cause a feeling of suffocation or pain when inhaling deeply, and lead to coughing, throat irritation, and chest discomfort. Furthermore, it inflames and damages the airways, aggravates conditions such as asthma, chronic bronchitis, or emphysema, and increases the frequency of asthma attacks in people already diagnosed.
Ozone can also cause the lungs are more vulnerable to infections and continue to damage lung tissue even when symptoms are no longer clearly noticeable. Repeated exposure to high levels is linked to the development of chronic obstructive pulmonary disease (COPD) or to the worsening of this condition in those who already have it.
Another key gas in assessing Greek air quality is sulfur dioxide (SO₂)It is a colorless gas with a strong, unpleasant odor, which is mainly generated by burning fossil fuels containing sulfur (coal, fuel oil) for heating, electricity generation or industrial use, as well as in processes of smelting sulfide minerals.
Short-term exposures to high concentrations of SO₂ They can significantly irritate the respiratory system and make breathing difficult, especially in people with asthma. SO₂ reacts readily in the atmosphere with other compounds to form acids such as sulfuric and sulfurous acids, as well as sulfate particles, contributing to acid rain and the deterioration of sensitive ecosystems. Children, the elderly, and people with respiratory illnesses are the most vulnerable to its effects.
El nitrogen dioxide (NO₂) Carbon monoxide is another major contributor to urban pollution in Greece and the rest of Europe. It is a reddish-brown gas with a pungent odor, produced primarily by the burning of fossil fuels (coal, oil, gas) in power plants, boilers, and, most notably, in vehicle and ship engines.
In large metropolitan areas, the main source of NO₂ are the exhaust pipes of vehiclesespecially diesel. This gas is not only harmful in itself: it also acts as a precursor in the formation of tropospheric ozone and secondary particles, thus indirectly influencing several components of the air quality index.
Nitrogen dioxide irritates the lining of the lungs and reduces the body's capacity to combat respiratory infections. Prolonged or repeated exposure can cause or aggravate problems such as wheezing, persistent cough, frequent colds, flu-like episodes, and bronchitis, and is of particular concern in areas of heavy urban traffic.
Finally, the carbon monoxide (CO) It is a colorless and odorless gas that forms during incomplete combustion of fuels. Although it doesn't always appear as prominently on air quality maps as other pollutants, it remains an important indicator, especially in poorly ventilated environments or areas with heavy traffic.
When inhaled at high concentrations, the CO interferes with oxygen transport in the blood, potentially causing headaches, dizziness, nausea, and vomiting. Repeated exposure over time, even at lower levels, has been linked to cardiovascular problems and an increased risk for people with pre-existing heart conditions.
Impact on health and recommendations for the population in Greece
All these pollutants—particulate matter, ozone, SO₂, NO₂, and CO—end up being reflected in the air quality index that we see for different areas of GreeceBut its real effect translates into very specific symptoms and illnesses. That's why it's important not to focus solely on the index number, but to understand what it can mean for your health.
On days with high levels of PM10 or PM2.5Eye and throat irritations, coughing, shortness of breath, or asthma attacks may appear or worsen. Repeated exposure to fine particulate matter is also linked to the development and worsening of chronic respiratory diseases and an increase in cardiovascular problems, especially in the elderly and people with pre-existing conditions.
In the case of ground-level ozoneThe effects are most noticeable during the middle of the day, when solar radiation is most intense and photochemical reactions are most active. Sensitive individuals may find it difficult to breathe deeply, experience chest pressure, or be more easily triggered by asthma attacks. Reducing strenuous outdoor physical activity during these times is usually a good preventative measure.
Pollutants such as nitrogen dioxide and sulfur dioxide They further increase the risk for vulnerable groups: children, the elderly, pregnant women, and patients with asthma, chronic bronchitis, COPD, or heart disease. During periods of high pollution, it is recommended to avoid areas with heavy traffic, close windows if the outside air is very unhealthy, and closely follow the warnings issued by health authorities.
The recommendations for the population in Greece also include paying attention to the Saharan dust peaksThese storms can significantly increase particle concentrations, even if only for a few days. Warnings are usually issued when these dust-laden air masses are expected, and during these periods it's advisable to reduce strenuous outdoor activities, especially for more sensitive individuals.
Technological solutions and air monitoring systems
In response to growing concerns about air quality, multiple initiatives have emerged in recent years. Technological solutions to monitor and improve the atmosphere in cities, also applicable to the Greek context. These initiatives are often integrated into "smart city" projects that seek to combine environmental data, mobility, and public health.
Among the most widespread tools are the air quality monitors High-resolution sensors are installed on streetlights, public buildings, schools, and transportation hubs. These devices measure levels of key pollutants (PM2.5, PM10, NO₂, O₃, etc.) in near real-time and send the data to cloud platforms, where it is processed and displayed on maps or interactive panels.
They are also being developed drones equipped with environmental sensors They are capable of conducting systematic flights over specific areas to detect pollution hotspots, assess the dispersion of industrial fumes, or study how air quality varies with altitude. This information can be invaluable for planning green spaces, school routes, or changes in urban mobility.
Another line of work is the outdoor air purifiersThese devices are designed to filter particles and certain gases in particularly problematic areas, such as near busy roads, crowded squares, or school playgrounds. While they do not replace structural emissions reduction measures, they can serve as a supplement in places where exposure is high.
All these devices are usually connected to a data visualization platform This allows municipal technicians, researchers, and sometimes the public to analyze how pollution levels change throughout the day or year. In the case of Greece, integrating these technologies with official data and European models can provide a much more complete picture of the actual situation in each neighborhood or city.
WHO information on major pollutants
La World Health Organization (WHO) It has studied in depth the effects of the various air pollutants and has issued very specific guidelines on the risks associated with each one, which are fully applicable to the Greek context.
In the case of nitrogen dioxide (NO₂)The WHO highlights that the main anthropogenic sources are combustion processes, both in heating and power generation, as well as in vehicle and ship engines. Epidemiological studies indicate that prolonged exposure to NO₂ is associated with an increase in bronchitis symptoms in asthmatic children and with a higher frequency of reduced lung function in the general population.
According to the particulate matterThe WHO emphasizes that particles larger than 2,5 micrometers can be deposited in the respiratory tract and cause various health problems. Prolonged exposure can lead to eye and throat irritation, coughing, difficulty breathing, and worsening of asthma. If exposure is more frequent and higher, the health effects become more severe and can lead to chronic illnesses.
For sulfur dioxide (SO₂)The WHO states that it is a colorless gas with a strong odor that originates primarily from the burning of fossil fuels containing sulfur or from the processing of sulfide minerals. Exposure to SO₂ can affect the respiratory system and lung function, cause eye irritation, coughing, increased secretions, worsening of asthma and chronic bronchitis, and make people more susceptible to respiratory tract infections.
As to tropospheric ozoneThe WHO identifies it as one of the main components of photochemical smog. It forms when nitrogen oxides from vehicles and industries, along with volatile organic compounds emitted by solvents, fuels, or other sources, react in sunlight. The result is respiratory problems, exacerbation of asthma, reduced lung function, and the development or worsening of lung diseases.
The fine particles (PM2.5) They receive special attention from the WHO due to their ability to penetrate deep into the respiratory system and enter the bloodstream. The most severe impacts are observed in the lungs and heart, including an increase in asthma attacks, the development of chronic respiratory diseases, and a higher risk of serious cardiovascular events.
Finally, the carbon monoxide (CO) It is described by the WHO as a colorless and odorless gas that, when inhaled at high levels, can cause headaches, nausea, dizziness, and vomiting. Repeated and prolonged exposure has been linked to the onset or worsening of heart disease, due to its role in reducing the blood's capacity to carry oxygen.
All this body of scientific evidence serves as the basis for the reference values and air quality guidelines recommended by international health authorities and used by countries, including Greece, as a framework to establish their regulations and air quality improvement plans.
With all of the above in mind, the air quality index in Greece ceases to be just a number in an app and becomes a fundamental tool for to protect health, plan activities and guide public policiesKnowing what the colors mean, what pollutants are involved, what limitations the data has and what specific effects they can have on the body helps to make more informed decisions, both individually and collectively, in a country where the Mediterranean climate and episodes of Saharan dust add extra complexity to the air pollution equation.
