ADMS-Urban

World leading software for urban air quality management

What is ADMS-Urban?

ADMS-Urban pollution model is a comprehensive tool for tackling air pollution problems in cities and towns. It can be used to examine emissions from 6000 sources simultaneously.

ADMS-Urban is used to model the impact of major developments such as the Beijing Olympic Village, airport expansion and traffic management schemes. It is used to assess current and future air quality with respect to the air quality standards such as the EU Air Quality Directive, UK NAQS, US NAAQS, Chinese Class I, II and III and WHO guidelines.

Who uses ADMS-Urban?

ADMS-Urban is used across the world for air quality management and assessment studies of complex situations in towns, cities, motorways, counties and large industrial areas. It is currently being used in cities across Europe and Asia, including China, and also the USA to compare pollution levels with relevant air quality standards. In the UK, over 70 local authorities used the model to help with their review and assessment and in developing air pollution action plans and remedial strategies.

DEFRA (UK Department for the Environment, Food and Rural Affairs) has contracted CERC to use ADMS-Urban to model air pollutants in a number of urban areas in the UK (DEFRA project EPG 1/3/176), including London.

Why use ADMS-Urban?

ADMS-Urban is distinctive in its ability to describe in detail what happens on a range of scales, from the street scale to the city-wide scale, taking into account the whole range of relevant emission sources: traffic, industrial, commercial, domestic and other less well-defined sources.

The science of ADMS-Urban is significantly more advanced than that of most other air dispersion models (such as CALINE, ISC and R91) in that it incorporates the latest understanding of the boundary layer structure, and goes beyond the simplistic Pasquill-Gifford stability categories method with explicit calculation of important parameters. The model uses advanced algorithms for the height-dependence of wind speed, turbulence and stability to produce improved predictions.

Predicting pollutant concentrations from an urban area is a complex modelling problem. ADMS-Urban has been developed with a number of features to simplify the modelling process and help users. For example:

Visualisation	ADMS-Urban has links to ArcGIS and MapInfo Professional GIS (Geographical Information System) packages as well as Surfer contour plotting package. The GIS link can be used to enter and display input data and display output, usually as colour contour plots.
Emissions inventory	Source and emissions data can be imported from a Microsoft Access database created by the user or exported from CERC's Emissions Inventory Toolkit, EMIT. EMIT contains current and future emission factors including those for vehicles, industrial processes and fuel consumption.
Emission factors	The latest UK DMRB emission factors (released February 2003) can be used to calculate emissions from traffic flows and speeds.
Intelligent gridding	ADMS-Urban includes an intelligent gridding option which places extra output points in and adjacent to road sources to give excellent spatial resolution in areas of particular interest.
User-defined outputs	The user defines the pollutant, the averaging time (which may be an annual average or a shorter period), any percentiles and exceedence values that are of interest, and whether or not a rolling average is required. The output options are designed to be flexible to cater for the variety of air quality limits which can vary from country to country and over time.

Modelling scenarios and future years[top]

In most cases, ADMS-Urban is first used to model the emissions from a base case scenario, that is, data (emissions, meteorology, background, etc.) are used to produce results that can be verified against locally monitored data from a recent previous year or the current year. Once the base case scenario has been validated, it is possible to investigate different scenarios, for example:

Impact of major development

ADMS-Urban is often used to compare air quality before and after major developments. An emissions inventory is compiled using the best available estimates for after the development. ADMS-Urban allows many What if? scenarios to be tried out, predicting concentrations at key receptors or across a wider area.

Future years

The majority of air quality limits are objectives for future years. These scenarios can be modelled in ADMS-Urban using the DMRB emission factors for future years, future predictions from EMIT or the user's own estimate. Likely changes in traffic flows, fleet compositions and background concentrations if known, can also be included in the future scenarios.

Traffic management

If the predictions for future years indicate that concentrations of certain pollutants are likely to exceed the objectives, it is usual to consider traffic management and emission reduction scenarios. For example, some local authorities in the UK are considering introducing Low Emission Zones within which only vehicles that have achieved a particular low-emission standard are allowed. The effect on air quality of introducing such measures can be investigated using ADMS-Urban. CERC's Emissions Inventory Toolkit, EMIT can be used for investigating the effect on emissions.