Air Quality Video

The air quality video below explains about air quality and pollution in the Surrey County area.

This video is entitled "The Air We Breathe" and although it was produced in 1997, it contains very useful and interesting information about the air quality in this region still relevant today. This video is approximately 8 minutes in duration.

Overview of pollution in Surrey

The major source of air pollution in Surrey is from vehicle exhaust emissions. Surrey has a very high number of cars which are now subject to tight pollution standards first introduced in 1991. Car emissions must not exceed limits for carbon monoxide (a poisonous gas) or limits on hydrocarbons, arising from unburned fuel and oil.

Bonfires are one of the most common forms of complaint about air pollution in Surrey, with more than 2000 complaints made annually. Bonfires cause smells and produce smoke containing benzpyrene, which is a carcinogenic material. Garden waste is often burnt on bonfires to dispose of it, although a better way would be to shred or compost it.

Surrey generally has good air quality, but high levels of certain pollutants, such as nitrogen dioxide and particulates, may occur in town centres and close to major roads. Generally the further you are from main roads, the lower the concentration. In the Guildford area, the lowest recorded level of nitrogen dioxide is in the Chantry Woods - only 1 kilometre from the highest concentration in the town centre. Levels are lower in the Chantry Woods for three reasons:

• The site is free from main roads
• The vegetation and rural ozone mops up the nitrogen dioxide in the air
• The nitrogen dioxide diffuses and is dispersed by the wind

Other factors that affect pollution levels

Air pollution from Greater London can also effect Surrey when the wind is from that direction.

Pollution levels are also affected by the weather. When it is cold, pollution levels may rise because the pollutants do not disperse. However, when pollution does disperse, it may travel large distances - this is known as trans-boundary pollution as it travels across national borders.

The landscape can also play a part in how much pollution we experience. Hills, valleys and other geographical aspects can influence pollution on a local scale. A good example is in town and city centres where the "canyon effect" is recognised - pollution is walled in at the street level by high buildings and does not disperse.

Measuring pollution

Environmental Health Officers (EHO) in the Surrey region use a variety of techniques to monitor and measure pollution levels, including the nitrogen dioxide diffusion tube. These diffusion tubes are collected monthly from a range of sites in Surrey and use laboratory analysis to find out the concentrations.

The results will tell the what the average concentration of nitrogen dioxide has been at a particular site for the preceding month. While the diffusion tube is manual method, other techniques include using automatic monitoring stations.

You can see where the diffusion tube and automatic monitoring sites are within Surrey Heath by using the map on the air quality homepage.