Air Quality

Air Quality

European Union Air Quality Policy

Action to manage and improve air quality is largely driven by European (EU) legislation. The 2008 ambient air quality directive (2008/50/EC) sets legally binding limits for concentrations in outdoor air of major air pollutants that impact public health such as particulate matter (PM10 and PM2.5) and nitrogen dioxide (NO2). As well as having direct effects, these pollutants can combine in the atmosphere to form ozone, a harmful air pollutant (and potent greenhouse gas) which can be transported great distances by weather systems.

Separate legislation exists for emissions of air pollutants with the main legislation being the UNECE Gothenburg Protocol which sets national emission limits (ceilings) for SO2, NOX, NH3 and volatile organic compounds for countries to meet from 2010 onwards. Similar ceilings have since been set in European law under the 2001 National Emission Ceilings Directive (2001/81/EC), which was subsequently made into national law of Member States (in the UK, the National Emission Ceilings Regulations 2002).

The European Commission is required to review the directive in 2013 and it is expected that they will initiate work with stakeholders and Member States later in 2011. The review is expected to look at strengthening provisions for fine particulate matter (PM2.5) and consolidate the 4th Air Quality Daughter Directive.

European Union Air Quality Limits

There are a wide range of terms and concepts in national and international initiatives, for example, standards, objectives, target values and limit values. The EU Ambient Air Quality Directive and fourth Daughter Directive contain Limit Values and Target Values. The EU limit and target values with which the Estate members must comply are related to each National air quality objectives and strategies.


  • Air Quality Standards are concentrations recorded over a given time period, which are considered to be acceptable in terms of what is scientifically known about the effects of each pollutant on health and on the environment. They can also be used as a benchmark to indicate whether air pollution is getting better or worse.
  • An exceedence is a period of time (defined for each standard) where the concentration is higher than that set out in the Standard. In order to make useful comparisons between pollutants, (the Standards may be expressed in terms of different averaging times), the number of days on which an exceedence has been recorded is often reported.
  • An objective is the target date on which exceedences of a Standard must not exceed a specified number.
  • EU Limit values are legally binding EU parameters that must not be exceeded. Limit values are set for individual pollutants and are made up of a concentration value, an averaging time over which it is to be measured, the number of exceedences allowed per year, if any, and a date by which it must be achieved. Some pollutants have more than one limit value covering different endpoints or averaging times.
  • Target values – are used in some EU Directives and are set out in the same way as limit values. They are to be attained where possible by taking all necessary measures not entailing disproportionate costs.


The 2008 ambient air quality directive replaced nearly all the previous EU air quality legislation and was made law in England through the Air Quality Standards Regulations 2010, which also incorporates the 4th air quality daughter directive (2004/107/EC) that sets targets for levels in outdoor air of certain toxic heavy metals and polycyclic aromatic hydrocarbons. Equivalent regulations exist in Scotland, Wales and Northern Ireland.

Leave a Comment