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Dashboard (Tableau)

European city air quality viewer

Dashboard (Tableau)
Prod-ID: DAS-271-en
Published 17 Jun 2021
9 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, as long term exposure to air pollution causes the most serious health effects.

In 2021, the World Health Organization (WHO) updated its health-based guidelines for air quality, and recommended a maximum level of 5 μg/m3 for fine particulate matter for long term exposure in order to protect health. In 2008, the European Union (EU) set an annual limit value for fine particulate matter of 25 μg/munder policies to deliver clean air in Europe. The Ambient Air quality Directive 2008/50/EC is currently under revision to, among other things, align the EU standards more closely with the WHO recommendations.

The viewer categorises air quality as:

  • good for levels of fine particulate matter that do not exceed the annual guideline value of the World Health Organization of 5 μg/m3,
  • fair for levels above 5 and not exceeding 10 μg/m3
  • moderate for levels above 10 and not exceeding 15 μg/m3;
  • poor for levels above 15 and not exceeding 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 340 cities from across EEA member countries. Data comes from on the ground measurements of fine particulate matter, taken by over 400 monitoring stations.

The current version of the viewer includes links to the Urban PM2.5 Atlas produced by the European Commission’s Joint Research Centre. The Urban PM2.5 Atlas estimates the contribution that different sources of emissions make to the total PM2.5 concentration in 150 European cities. It also includes information about precursors pollutants that contribute to the formation of PM2.5Additional information on how to read the Urban PM2.5 Atlas pages can be found here.  

More information

 

Why are some cities missing?

If the city is not represented by a dot on the map, it means that the city could not be included in the viewer for one of the two reasons below.

  • The city is not included in the database of cities established under the European Commission’s Urban Audit.
  • The city does not have urban or suburban background or traffic air quality monitoring stations for PM2.5.

The dot representing a city on the map is grey when:

  • PM2.5 is only monitored at traffic stations; or
  • None of the urban/suburban background air quality monitoring stations in the city reported data covering more than 75% of the days in either of the two years considered.

     

How to use the viewer

Hover on a city on the map to see:

  • the city’s name and country
  • the city’s rank,
  • the average PM2.5 concentration over the past two full years
  • the air quality categorised as good, fair, moderate, poor or very poor,
  • the number of stations, regardless of their type, that measured fine particulate matter in the city (please be aware that, according to the description above, the city will be ranked only in the case of having background stations with enough data coverage)
  • the population of the city, according to the most recent EUROSTATdata and
  • a link to the information on the spatial and sectoral contributions to the city air pollution, from the Urban PM2.5 Atlas, when available. Some of the cities in the viewer are not covered by the Urban PM2.5 Atlas.

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, fair, moderate, poor and very poor, to display the cities with air quality in that category.

Clicking on a city on the map shows a detailed view of the locations of the PM2.5 monitoring stations, regardless of their type, in the city. The stations on the detailed map are represented according to average concentration of PM2.5 for the city as a whole. Hovering on the stations on the detailed map shows:

  • the station code
  • the station type
  • the city’s name and country
  • The country name
  • the average PM2.5 concentration at the station over the past two full years
  • the years included in the average
  • the average data coverage

 

Methodology

Which cities are included in the viewer?

The viewer presents cities as defined by the European Commission’s Urban Audit, in its 2020 edition. 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 2020 version of that dataset with the most recent population numbers from Eurostat).

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 annual average. This data is reported to the EEA on an hourly basis by member countries (known as E2a).
  • For the calendar year before last, data used 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 industrial stations and traffic 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 industrial areas and roads and do not measure the exposure of the general population. In addition, industrial and traffic stations are unevenly distributed in cities across Europe, which might introduce bias when making comparisons. Nevertheless, concentrations at traffic stations are shown when clicking on the cities, as explained above.

Air quality is also monitored in rural areas, with the aim, for instance, 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 its urban background stations and suburban background stations over the past calendar year. For this we use the up-to-date’ air quality data (E2a). Unrealistic concentrations above 1000 ug/m3 are removed from the E2a time series prior to the calculation of the average.
  2. We calculate the annual mean concentration of fine particulate matter for a city by averaging the daily means for all its urban background stations and suburban background stations 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, 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).

Which are the missing cities?

  • Cities that are not included in the database of cities established under the European Commission’s Urban Audit.
  • Cities that do not have any air quality monitoring stations for PM2.5 regardless of their type.
  • Cities that do not have urban and/or suburban background PM2.5 monitoring stations but have traffic monitoring stations are represented by a grey dot on the map and do not appear in the table.
  • Cities with urban and/or suburban background PM2.5 monitoring stations that have reported data with a temporal coverage less than 75% are represented by a grey dot on the map and do not appear in the table. 

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

We display five categories of air quality, including good, fair, 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 an annual air quality guideline for PM2.5 exposure of 5 μg/m3, as well as several interim targets. These values have been used to define the bandwidths for the five categories of air quality.

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

PM2.5 (μg/m3)
Interim target 1 35
Interim target 2 25
Interim target 3 15
Interim target 4 10
Air quality guideline level 5

 

Source: Adapted from WHO, 2021

 

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 differently. 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.

Information on the air quality of your city in the past years can be found in the Air quality statistics viewer. It presents information from the past years for all the air pollutants considered in the Ambient Air quality Directives.    

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 and here for the latest briefing on the status of air quality. 

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