Air Quality SPD

Ended on the 17 October 2018
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Annual average daily traffic flows

Air Quality Assessment (AQA)

An assessment of the impact of a development on the levels of certain pollutants in the local area and the impact of pollution levels on future occupants.

Air Quality Management Areas (AQMAs)

Areas where the air quality objectives are likely to be exceeded. Declared by way of an order issued under the Section 83(1) of the Environment Act 1995.

Air Quality Objectives

Air quality targets to be achieved locally as set out in the Air Quality Regulations 2000 and subsequent Regulations. Objectives are expressed as pollution concentrations over certain exposure periods, which should be achieved by a specific target date. Some objectives are based on long term exposure (e.g. annual averages), with some based on short term objectives. Objectives only apply where a member of the public may be exposed to pollution over the relevant averaging time.

Clean Air Zones (CAZ)

Zone implemented by a local authority setting nationally set emission standards for vehicles. Non-charging zones can be implemented through policies covering bus and taxi emissions. Charging zones require non-compliant lorries and possibly vans to pay a charge to enter the zone.

Damage costs

Damage costs are a simple way to value changes in air pollution. They estimate the cost to society of a change in emissions of different pollutants

Environmental Impact Assessment (EIA)

Assessment required for projects specified in Environmental Impact Assessment Directive. Governed by the Town & Country Planning (Environmental Impact Assessment) Regulations 2017

EU Limit Value

Legally binding pollutant concentration limit on Governments of EU Countries

Euro Standards

European Emission Standard (progressively tightened emission standards for vehicles. Euro Standards for cars and small vans are stated in Hindu-Arabic numbers and HDVs in Roman numerals)


Concentrations of a specified air pollutant greater than the appropriate Air Quality Objective.


Heavy duty vehicle (lorry or bus greater than 3.5 tonnes gross vehicle weight)


Local Air Quality Management Technical Guidance (2018). This document provides national advice on how local authorities should assess air quality.

Low Emission Strategy (LES)

Overarching council strategy to integrate policies and practices to achieve year on year vehicle emission reductions, optimising opportunities for national funding assistance

Low Emission Zone (LEZ)

Council area in which emission standards apply for either road transport vehicles or power generation/industrial emissions. The council can set emission standards that differ in standard and scope from the Government requirements for implementing Clean Air Zones for vehicles


Light duty vehicle (car or small van less than 3.5 tonnes gross vehicle weight

Limit Values/EU limit values

The maximum pollutant levels set out in the EU Daughter Directives on Air Quality. In some cases the limit values are the same as the national air quality objective, but may allow a longer period for achieving.


Mitigation measures will minimise, but not necessarily remove, the impact of or effect of poor air quality on a development

National Air Quality Objectives

See Air Quality Objectives

National Air Quality Plan

Government Plan to improve roadside concentrations of nitrogen dioxide (July 2017)

Non-road mobile machinery (NRMM)

Diggers, cranes, bulldozers, plant etc used on construction sites


Nitrogen dioxide


NOx = nitrogen oxides, which includes nitric oxide and nitrogen dioxide. Most pollution sources emit nitrogen oxides primarily as nitric oxide. However, once in the atmosphere nitric oxide can be converted to nitrogen dioxide. Therefore, it is important to know the concentrations of both NOx and NO2


Measures which 'compensate' for anticipated increases in pollution in the area but not necessarily at the exact locality. This might be for example by funding more general measures in the air quality action plan.


Particulate matter


Particulate matter with a diameter of 2.5 microns or less


Particulate matter with a diameter of 10 microns or less.

Part A1 and A2 Processes

Industrial processes which are regulated under the Pollution Prevention and Control (PPC) Regulations and subsequent Integrated Pollution Prevention and Control (IPPC) for emissions to all media (i.e. atmosphere, land and water).

Part B Processes

Industrial processes which are regulated under the Local Air Pollution Control (LAPC) and Local Air Quality Pollution Prevention and Control (LAPPC) Regulations for emissions to air only.

Point sources


Polluting development

A development which will directly or indirectly increase levels of relevant pollutants. This may include industrial processes but may also include developments which could cause increased traffic emissions.

Sensitive development

A development which would allow users of the site to potentially be exposed to pollutants above the objective for the relevant period. For example, the introduction of a new residential development into an area where an air quality objective is already exceeded, would create the potential for the exposure of residents to poor air quality above the objective. Incidentally, this type of development may also generate significant additional traffic flow and also be a polluting development.

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