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Dashboard (Tableau)

European city air quality viewer

Dashboard (Tableau)
Prod-ID: DAS-271-en
Published 17 Jun 2021
7 min read
Topics:
Policies to reduce air pollution have led to improved air quality in Europe over the last three decades. However, in some European cities air pollution still poses risks to health. You can use the European city air viewer to check how the air quality was in your city over the past two years and to compare it with air quality in other cities across Europe.

Cities are ranked from the cleanest city to the most polluted, on the basis of average levels of fine particulate matter, or PM2.5, over the past two calendar years.

Fine particulate matter is the air pollutant with the highest impact on health in terms of premature death and disease. This tool is focused on long term air quality, with long term exposure to air pollution causing serious health effects.

The World Health Organization has established a health-based guideline for long term exposure to fine particulate matter of 10 μg/m3. The European Union has set an annual limit value for fine particulate matter of 25 μg/m3 under policies to deliver clean air in Europe.

The viewer presents air quality as:

  • good for levels of fine particulate matter that are under the annual guideline value of the World Health Organization of 10 μg/m3,
  • moderate for levels from 10 to below 15 μg/m3;
  • poor for levels from 15 to below 25 μg/m3; and   
  • very poor for levels at and above the European Union limit value of 25 μg/m3.

In Europe, we benefit from the most comprehensive air quality monitoring network in the world. Here we present levels of fine particulate matter in over 300 cities from across EEA member countries. Data comes from on the ground measurements of fine particulate matter, taken by over 400 monitoring stations.

 

  

  

More information

 

Why are some cities missing?

If the dot representing a city in the map and the city name in the table are grey, then the city could not be included in the viewer for one of the three reasons below.

  • The city does not have urban or suburban air quality monitoring stations.
  • The urban and/or suburban air quality monitoring stations in the city have not reported data covering 75% of the days in the year.  
  • The city is not included in the database of cities established under the European Commission’s Urban Audit.

How to use the viewer

Click on a city to see:

  • the city’s rank,
  • the air quality categorised as good, moderate, poor or very poor,
  • the average concentration over the past two full years
  • the number of stations that measured fine particulate matter in the city and a pop-up map showing their location, and
  • the population of the city.

The table ranks European cities according to their average levels of fine particulate matter over the past two full calendar years.

You can click on the air quality categories, good, moderate, poor and very poor, to display the cities with air quality in that category.

 

Methodology

Which cities are included in the viewer?

The viewer presents cities as defined by the European Commission’s Urban Audit. This geospatial dataset includes cities with a population over 50,000 inhabitants. A similar dataset is available for download from the Eurostat website (note that the European City Air Quality Viewer uses a processed 2014 version of that dataset with population numbers from 2011).

What data do we use?

We use data on concentration of fine particulate matter, or PM2.5, reported to the EEA by our member countries under the European Union Ambient Air Quality Directives. Two types of data are used.

  • For the last full calendar year, ‘Up-to-date’ air quality data is used to calculate the average for the past year. This data is reported to the EEA on an hourly basis by member countries (known as E2a).
  • For the calendar year before last, data that has been officially validated by the countries prior to being reported to the EEA (known as dataflow E1a).

Why do we focus on particulate matter?

Fine particulate matter is the air pollutant with the highest impact on health in terms of premature death and disease. Long term exposure to air pollution is associated with the most serious health outcomes, including cardiovascular and respiratory diseases.  

What air quality monitoring stations does the data come from?

To produce this tool, we use data from urban background and suburban background air quality monitoring stations that are situated within the boundaries of the cities, as defined by the Urban Audit, and for which countries report data to the EEA. These stations provide a robust picture of the exposure of the population to air pollution in cities.

Air quality is also measured at traffic stations and industrial stations. Data from these stations are not used for this tool, as they are used to measure levels in more polluted areas, such as around industrial sites and near motorways and major roads with dense traffic. As such, they measure the exposure of populations around major roads and do not measure the exposure of the general population. In addition, traffic stations are unevenly distributed in cities across Europe, which might introduce bias when making comparisons.

Air quality is also monitoring in rural areas, with the aim of understanding impacts on crops and natural ecosystem. Rural stations tend to be located away from the cities and are not included in this tool.

How do calculate the average concentrations of fine particulate matter over the past two years?

  1. We calculate the annual mean concentration of fine particulate matter for a city by averaging the daily means for all urban background stations and suburban background stations in a city over the past calendar year. For this we use the up-to-date’ air quality data (E2a).
  2. We calculate the annual mean concentration of fine particulate matter for a city by averaging the daily means for all urban background stations and suburban background stations in a city over the year before last. For this we used the validated air quality data (E1a).
  3. We use the results of step 1 and 2 to calculate the mean concentration across those two calendar years.

For some cities, we do not have data for either step 1 or step 2. In such cases, we use the annual mean for the available year. 

What are the requirements for data coverage?

For data from a station to be included, then a minimum of 75% temporal data coverage is required. This means that for an individual station, we consider those with more than 274 valid daily values per calendar year (or 275 days in a leap year).

Why are some cities missing?

  • Cities that do not have urban monitoring stations or suburban monitoring stations are not included.
  • Cities with urban and/or suburban monitoring stations that have reported data with a temporal coverage less than 75% are not included.  
  • Cities that are not included in the database of cities established under the European Commission’s Urban Audit.

What is the scientific basis for the different categories of air quality?  

We display four categories of air quality, including good, moderate, poor and very poor. These are defined by bandwidths of concentrations of fine particulate matter, as shown below.

 

In their guidelines for air quality, the World Health Organization established a lower annual air quality guideline for PM2.5 exposure of 10 μg/m3, as well as several interim targets. These values have been used to define the bandwidths for the four categories of air quality.

Table: WHO air quality guidelines and interim targeted for fine particulate matter, annual mean concentrations

 

PM2.5 (μg/m3)

Basis for the selected level

Interim target 1

35

These levels are associated with about a 15% higher long-term mortality risk relative to the air quality guideline

Interim target 2

25

In addition to other health benefits, these levels lower the risk of premature mortality by approximately 6 % (2-11%) relative to interim target 1.

Interim target 3

15

In addition to other health benefits, these levels lower the risk of premature mortality by approximately 6 % (2-11%) relative to interim target 2.

Air quality guideline

10

These are the lowest levels at which total, cardiopulmonary and lung cancer mortality have been shown o increase with more than 95% confidence in response to long-term exposure to PM2.5.  

 

Source: Adapted from WHO, 2005

 

What are the uncertainties?

All measurement methods used have a degree of error. In particular, the up-to-date data (dataflow E2a) is not checked for outlying datapoints, which may be errors, and validated by the countries. This may introduce a limited number of more extreme values to the dataset.  

In reporting the characteristics of monitoring stations to the EEA, countries may interpret the definitions of station types different. This can reduce comparability between cities.

It is assumed that all the urban and suburban monitoring stations in a single city represent background environments equally. The methodology does not account for the distribution of the urban population across the city. Treating stations equally may lead to an underestimate of the average concentration that the general population is exposed to, in the case where the area around a pollution hotspot is densely populated.

In large cities with dense urban centres where large parts of the population reside, stations in the city centre are likely to be traffic stations. Such stations are not included in the methodology and this may lead to an underestimation of concentrations of fine particulate matter.

Only measurements from urban and suburban stations that are in the urban audit geometries are considered in the calculations. 

Links to other EEA products

If you want to know what the air quality is in your city today, please visit the European Air Quality Index. The index presents information on air quality over the past two days and a 24-hour forecast, together with health-based recommendations for short term exposure to air pollution. It also covers a broader range of air pollutants, including particulate matter, nitrogen dioxide, sulphur dioxide and ozone.   

More information on the health impacts of air pollution in Europe is available here.

See here for the European Environment Agency’s latest annual report on air quality in Europe.  

 

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