Population weighted annual mean PM2.5 in cities

Data source
PM10 and PM2.5 data: data compiled from AirBase (13), with additional data provided by the European Environmental Agency (EEA). For Belarus and Russian federation: national data sources.
Population data: WHO’s Health for All Database HFA-DB (14) and Urban Audit database (15).
Percentage of population living in cities: HFA-DB (14).

Description of data
PM10 and PM2.5 monitoring data are submitted by national authorities to the AIRBASE of the European Environment Agency. Only data from urban or suburban background monitoring stations, for which PM measurements are available for at least 75% of days in the year, were used in this analysis. Monitoring stations located near heavy traffic or industrial sites were excluded from this analysis. Data quality check and verification of the station’s location classification are carried out by the European Topic Centre on Air and Climate Change (16).
For several countries, the assessment is based on data from one, or few, cities only. In five countries, coverage of the urban population was 20% or less in 2011.

Method of calculating the indicator
Exp = SUM {(Pi/P)*Ci}, where:
Ci = annual mean PM10 or PM2.5 concentration in sub-population Pi,
P = SUM (Pi), which is the total population in cities with data.

Geographical coverage
All data from cities with PM10 or PM2.5 measured in urban (or suburban) background locations included in the AirBase have been used for this analysis (Table 1 & 2). In addition, data obtained by WHO from Belarus and the Russian Federation (Moscow only) were used. PM10 and PM2.5 monitoring is not conducted in many of the non-EU countries, which makes it difficult to assess exposure in those parts of the Region.

Period of coverage
PM10 and PM2.5 data used in this analysis cover the period from 2004 to 2011. Data from earlier years are only available for a limited number of countries. In the EU, PM10 and PM2.5 monitoring is required under the EU Directive 2008/50/EC. (8).

Frequency of update
Air quality data (daily concentration of PM10 and PM2.5) are submitted by national authorities to AirBase annually. After data quality checks and data processing, the data are made available on-line (with a delay of about one year). Although city-specific population data are updated less frequently, it does not affect the indicator values appreciably due to the relative stability of European urban populations.

Data quality
Quality assurance and control procedures apply to the PM10 and PM2.5 data submitted to AirBase (13).