The cause of air pollution in the city is largely due to both road transport and industry, and to a lesser extent, other processes that burn fossil fuels, such as commercial or domestic heating systems (for example gas boilers).
We have a statutory duty to manage local air quality in Sheffield under the Environment Act 1995.
We declared an Air Quality Management Area in March 2010 across the whole of the urban area of the city for nitrogen dioxide (NO2) gas and fine particulate matter (PM10) dust. This is because we didn't meet the standards set in the national Air Quality Strategy.
Our Air Quality Action Plan describes the actions that have been taken since 2010 to improve air quality and what more needs to be done. It aims to reduce pollution in Sheffield in order to achieve health-based national air quality objective and EU limit values by 2015.
About the pollutants
Pollutants mainly come from human activities such as from industry, road traffic and building heating. Some come from natural sources such as wind blowing dust about and decomposing organic matter.
The pollutants in Sheffield we are mainly concerned about are Nitrogen Dioxide (NO2) and fine particulate matter (PM10 and PM2.5). They come from burning diesel and also petrol, gas, wood and coal.
Other pollutants of less concern include Sulphur Dioxide (SO2), Carbon Monoxide (CO), Ozone (O3), Lead (Pb) and 1,3-Butadiene.
Health problems from pollutants
Pollutants cause the following health problems:
- Nitrogen Dioxide, Sulphur Dioxide, Ozone – these gases irritate the airways of the lungs and increase the symptoms of people suffering from lung diseases
- fine particulate matter can travel deep into the lungs where they can cause inflammation and a worsening of heart and lung diseases
- Carbon Monoxide prevents the uptake of oxygen by the blood. This can lead to a significant reduction in the supply of oxygen to the heart, particularly in people suffering from heart disease
Air pollution also causes damage to plants and animals, and affects biodiversity and crop yields.
The air quality of Sheffield is measured 24 hours a day 365 days a year by both sophisticated automatic equipment, and simple manual methods.
We currently own 6 automatic monitoring stations, measuring a variety of pollutants. The locations of the sites vary from time to time. In general they are sited in areas where we think air pollution may be at risk of going above Government air pollution objectives.
We have automatic air quality monitors sited at:
- Tinsley Infant School - measuring fine particles (PM10 and PM2.5) and nitrogen dioxide
- Lowfield School - measuring fine particles (PM10), sulphur dioxide and nitrogen dioxide
- King Ecgbert's Old School Site - measuring fine particles (PM10), ozone and nitrogen dioxide
- Wicker - measuring fine particles (PM10), ozone and nitrogen dioxide
- Fir Vale School - measuring fine particles (PM10), sulphur dioxide and nitrogen dioxide
- Waingate - measuring fine particles (PM10) and nitrogen dioxide
In addition there are 2 sites owned by the Department for Environment, Food and Rural Affairs (DEFRA). These are stationary sites in the city centre and Tinsley.
Nitrogen dioxide levels are also monitored at around 160 locations across Sheffield by ourselves and a number of community groups. Instead of complex and expensive analysers, simple passive diffusion tubes are used.
The tubes are cheap, manual, yet reliable indicators of air pollution.
Predicting Air Quality
In areas of Sheffield where we do not measure air pollution, we use a sophisticated Dispersion Model called Airviro, to predict the levels there.
We also use the model to forecast the likely future levels of air pollution in all areas of the city and to decide whether we will breach Government objectives and EU limit values or not.
Airviro takes into account hills, wind, temperature, cloud cover and the amount of pollution coming from different sources (eg road traffic, industry, commercial and residential heating).