The first real advancement in air pollution control legislation came through the Clean Air Act 1956. This was introduced almost directly as a result of the London smog of 1952. This Act was updated and amended by the Clean Air Act 1968, and then later repealed once more, and consolidated along with air legislation from the Control of Pollution Act 1974 and the Control of Smoke Pollution Act 1989 to give the Clean Air Act 1993.

There were 4 main provisions within the Clean Air Acts:

1. The Creation of Smoke Control Areas.

   This was basically a ‘planning control’, where the local authority established areas where smoke from domestic premises was disallowed. Industry wasn’t exempt either although there was a long list of specified exempted boilers/fireplaces, which effectively eased the burden on industry. Under the Act, the only smoke allowed is ‘smoke derived from the combustion of an authorised fuel’. The unauthorised fuels are generally wood, coal, and oil, unless they have been treated in such a way that they will not give rise to the formation of any smoke.

2. The Prohibition of Dark Smoke from any Chimney.

   This was originally aimed at Industry. However today, by means of the ‘93 Act this can now apply to any type of building. In order to define dark smoke an identity chart was introduced (in 1958) known as the Ringleman’s Chart. It was suggested that this was to be held up against the offending chimney, and if the shade of the emissions exceeded Shade 2 on the chart, then the smoke was Dark.

   
   

   There are a number of exemptions to all of this as provided by the Clean Air (Emission of Dark Smoke) (Exemption) Regulations 1969:

   • The burning of material on a demolition site (apart from rubber or feathers)
   • The combusting of explosives
   • Material burnt for the purposes of fire research
   • Bituminous materials used for road surfacing, roofing etc
   • The burning of animals that have died from disease

   These exemptions are subject to the proviso that:

   • No other method of disposal available at the time
   • To be carried out with minimal production of black smoke

   Other defences from the Dark Smoke (Permitted Periods) Regs. 1958 allow:

   • Starting from cold
   • Smoke through mechanical failure
   • Unavoidable use of an unsuitable fuel
   • Dark smoke may also be produced for a limited period of time in any 8 hour period, dependent upon the number of furnaces in use, (ie.1 furnace - 10 minutes)
   
   
3. The Installing of Dust and Grit Arresters

   The basis of this was that certain new furnaces (unless exempted) had from now on, to be fitted with arresters for control of dust and grit. This did not apply to domestic appliances. (They were distinguishable by their burning capacity).

   
   
4. Chimney Heights

   All chimney heights must be approved by the local authority.There are a number of documents currently available, such as the commonly used guidance document written by Hall, Kukadia, and Emmott. The height of the chimney is now calculated after careful consideration of the following:

   • the characteristics of the flue gases
   • the rate of emission
   • the quality of the emission (eg. optical density of the plume)
   • the sulphur content of the fuel burned
   • the characteristics of the surrounding area
   • the location of nearby buildings
   • the height of nearby windows
   • the local topography
   • the prevailing wind directions

The fundamental aspect of this being that it introduced the cross-media approach to pollution control that had been sadly lacking. For the first time in our pollution control history, we realised that the control of pollution to one medium could, and more often did, have a detrimental effect on one or more other media.

Air pollution control is covered in Part 1 of the Act.

Basically, the Act attempted to introduce a complete new approach to controlling industrial airborne emissions. The cornerstone being:

• the introduction of Integrated Pollution Control (IPC) ( a cross-media approach to pollution control)
• new powers to local authorities in dealing with air pollution
• a new regulatory body for IPC, HMIP…… now the EA

• changing the process or product specifications
• changing the process technology, (making it more efficient)
• training operatives to perform to a specified standard
• install equipment that prevents release of harmful emissions into the environment

One of the primary aims of this legislation was to consolidate IPC/IPPC. This was partially achieved by setting up the Environment Agency, as the primary regulator.

However, air quality is covered in Part IV of the Act, and its approach differs from that of the EPA90 in the fact that while the EPA90 has its basis in the regulation of industrial emissions (and dealing with pollution at source) the EA95 deals more with overall air quality.

One aim of the Act was to produce the UK National Air Quality Strategy. The purpose of which being:

• To identify air quality standards
• To state the long-term objectives for reducing levels of airborne pollution
• To propose the action to be taken by central Government, in order to meet these objectives
• To propose action to be taken by the local authorities, in order to meet these objectives

• promoting alternative fuels
• the continual control over vehicle emissions
• fuel quality standards
• restrictions on vehicle fleets
• tighter BAT controls on industry

• Identify which standards are not being met
• Identify the reasons why they are not being met
• Propose a method of meeting them in future by drawing up an action plan

• the introduction of local transport plans
• targets for traffic reduction, air pollution, public transport, cycling, and walking
• road charging schemes
• car parking taxation
• investment in public transport
• networked public transport across the whole country
• road building projects
• reduction in road freight
• targets to reduce driving distances by 20%
• tax concessions on the use of alternative fuels

• roadside testing of vehicular emissions, with a roadside fixed-fine system for excess emissions
• the introduction of fiscal measures to reduce vehicle numbers (ie. by offering financial incentives for car-sharing, or through direct taxation/penalisation ie. increase fines, parking fees etc.)
• bus and cycling prioritisation
• increased areas of pedestrianisation, and/or reduction in parking areas
• temporary prohibition of vehicles during peak emission periods