Can cause permanent lung damage even in the healthy by increasing mucous production causing choking and impaired lung function. Urban air pollution has many sources. Whilst vehicle emissions have the single largest impact on ground level concentrations of most urban air pollutants, other sources have some effect. Many of these pollutants in urban areas arise from the combustion process and urban areas contain a wide variety of these which arise from domestic and commercial activity as well as industry. This has led, not surprisingly, to a rapid increase in UK air pollution emissions, despite the recent introduction of emission controls.
Diesel engines emit small particles, which are known to be toxic.
Perhaps, one of the main pollutants from domestic sources, which effects urban air quality is black smoke, in areas where coal is still being used. Belfast is a prime example of this. Domestic sources cause emissions of nitrogen dioxide into the atmosphere through the use of gas fired appliances and oil stoves. Power stations are still a the of urban air pollution. Power generation may release sulphur dioxide and nitrogen dioxide into the atmosphere.