Paul Landau highlights the sources of both data and information on air-pollution measurements — both nationally and internationally — and summarises a selection of the main databases available.

Throughout the European Union (EU), there are many thousands of automatic, continuous monitoring systems for measuring ambient air quality and industrial emissions, monitoring a wide variety of regulated pollutants. Each one of these instruments will typically take a reading over 10 seconds, and then use these 10-second values to calculate a one-minute average. These one-minute averages, in turn, are then stored within data-recording systems, which will then calculate both short and long-term averages as required by legislation.

Such instruments for measuring air pollution are designed and installed with the aim of taking measurements every hour of every day. Even taking into account some time offline for both scheduled and unscheduled maintenance, such instruments will each typically amass around half a million one-minute averages each year. Taking into account the vast number of automatic monitors scattered and clustered throughout Europe, this results in a huge volume of air-pollution data.

Additionally, many regulated industries may have to calculate their emissions using empirical, validated methods, especially when such emissions do not have to be directly measured.

For anyone needing to examine or use these different types of data, both accessing the data and then making sense of it can be a complex and daunting task. Fortunately, both national and international organisations have already processed, summarised and arranged the data to make it readily accessible, while for those wishing to go further and perform their own analyses, there are publicly available tools to do this too.

Both national and international sources of available databases typically fall within five types.

  1. Statistical summaries of data and trends.

  2. On-line measurements and archived data, showing averaged values for regulatory purposes.

  3. Inventories of data compiled from either measurements or empirically calculated values.

  4. Gateway sites that provide simplified, targeted and often filtered links to complex databases.

  5. Tools for analysing data, and applications of analysed data.

The main national and international databases will be covered in the next section, with their website locations listed in Table 1.

National databases

The principle air quality and emissions databases in the UK are managed by the Department for Environment, Food and Rural Affairs (Defra), often in partnership with other organisations, such as sub-departments within Defra, national environmental regulators and universities. In terms of data, there are three main UK-wide sources of air-quality and emissions data.

  • Database of National Air Quality Statistics1: This includes summary data on ambient concentrations and emissions of air pollutants that are included within the National Air Quality Strategy (eg benzene, 1,3-butadiene, carbon monoxide, sulphur dioxide nitrogen oxides, particulate matter as PM10 and PM2.5, ozone and lead). The site also includes summary data and information on 16 other pollutants, including heavy metals in addition to lead, and toxic organic micro-pollutants. The database includes data and summaries of long-term trends in air quality.

  • UK Ambient Air-Quality Database2: This source is the primary portal for ambient air-quality data in the UK. It includes live data from automatic networks required by EC legislation, applied through national regulations. The site is also a gateway with links to sites managed by local authorities in the UK. As well as live data, it includes huge volumes of archived data. Data from the site is used within the database on National Air Quality Statistics, while the database also includes information on the different monitoring networks, covering both automated and non-automated monitoring stations.

  • National Atmospheric Emissions Inventory (NAEI)3: This database contains emissions data from industrial and transport sources, required by legislation such as the National Emissions Ceiling Directive and Convention on the Long Range Transport of Air Pollution (CLRTAP).

While the NAEI is wide ranging, there are also specific emissions inventories, such as the Greenhouse Gas Inventory4 operated by the Department of Energy and Climate Change, and the national Pollution Inventory5 for industrial sources managed by the Environment Agency. The Environment Agency also operates a database called What’s In My Backyard?6, which allows a user to determine which specific industrial sites are located within a specified area, together with a summary of the releases from any local sources.

There are also gateway sites for inventories and air-quality databases, such as a website operated by the Scottish Executive7, which provides links to data for emissions and ambient air quality in Scotland, and The London Air Quality Network8, which focuses on the London-based monitoring stations in the national Automatic Urban Network. The Northern Ireland Environment Agency and Scottish Environmental Protection Agency also host gateway sites.

The UK has two sources notable for applying monitoring data; the first of these, the OpenAir Project9, is managed by the Environmental Research Group at King's College London, in collaboration with the University of Leeds, and supported by the Natural Environment Research Council. The purpose of the OpenAir Project is to provide a set of freely available tools to analyse air-pollution data, enabling users, for example, to perform statistical analyses of trends and to compare different sets of data.

The second source for applying air-pollution data is the UK Air Pollution Information System (APIS)10, a database of the effects of air pollution on habitats and species. APIS is supported by several bodies and regulators in environmental research and protection, such as the Environment Agency, Natural England and Scottish Natural Heritage.

International databases

For anyone investigating local air quality or national air quality and emissions for projects such as environmental research, environmental impact assessments for planning applications, or permit applications, then the national databases should be able to provide sufficient data and information. However, if a wider perspective is required, such as a comparison with air quality or emissions in other European countries, there are a number of sources which can provide this information.

For example, EioNet11 is a gateway site for databases on a variety of releases of pollutants and air quality, including industrial emissions, GHG emissions, and ambient air quality. EioNet is operated by the European Commission, while several of the databases are hosted by the European Environment Agency (EAA) in Copenhagen. One of these EAA databases is Airbase12; this is a publicly accessible database containing data and information on ambient air quality for over 30 nations throughout Europe. Each year, for example, European countries have to report their data in ambient air quality for air pollutants, using data from a representative selection of stations. The reporting must follow the requirements of the Council Decision 97/101/EC, a reciprocal Exchange of Information on ambient air quality.

The EAA also manages databases for air emissions and greenhouses gases. It uses the data and information from these databases for the reports required for annual EU inventories, and for the two UN conventions on climate change and the long-range transport of air pollutants.

Finally, the World Health Organization manages a database called Air Pollution in Cities13. This database hosts the measurements of urban air-pollution monitoring for around 1100 cities located in 91 nations. The measurements focus on the annual mean concentrations of respirable particulate matter, ie PM10 and PM2.5. The data covers the years from 2003 to 2010, while the main sources of data are publicly available international sources such as Airbase and the Asian Clean Air Initiative, national sources of data, regional networks, and selected publications. The developers of the database planned it to be representative for assessing human exposure, and hence mainly uses measurements from monitoring stations sited in urban-background locations, sites with traffic, and residential and commercial areas. An examination of the data shows, for example, that the average exposure to PM10 globally is 71µg.m3 — well above the daily EC limit value of 50µg.m3 — while the regional values vary between around 20µg.m3 to 142µg.m3. In summary, for anyone needing to access anything from raw ambient air-quality data to tools for analyses summaries of measurements on air pollution, there are several sources available both in the UK and beyond.

Table 1




Defra Air Quality Statistics

A variety of summary statistics on statistics, with links to sites on emissions and air quality.


UK Air Quality

Live air-quality data, archived data, and information on monitoring networks


National Atmospheric Emissions Inventory

The UK’s emissions from industry and transport


UK GHG Inventory – National System

The UK’s emissions of GHGs


Pollution Inventory

An inventory of industrial emissions, required by EC legislation


What’s In My Backyard?

The Environment Agency’s site for determining localised sources and their reported emissions for the Pollution Inventory


NAEI and LAQD for Scotland

A gateway to parent sites for emissions data and air-quality data, focusing on Scotland


London Air Quality Network

A gateway specific to London’s air-quality network of monitoring stations


OpenAir Project

A set of freely available tools for analysing air-pollution data


UK Air Pollution Information System (APIS)

Provides a searchable database and information on pollutants and their impacts on habitats and species

International sites



A gateway for databases on industrial emissions, GHG emissions, and ambient air quality



Ambient air quality in 30 European countries


World Health Organization — Air Pollution in Cities

Air quality for PM10 and PM2.5 in major cities worldwide

Last reviewed 11 April 2012