Forty years ago, smoke and sulphur dioxide pollution from domestic coal burning caused an air pollution episode that led to the premature deaths of 4,000 Londoners. These so-called smogs have been all but eliminated by a combination of measures of which the most important were the Clean Air Acts of 1956 and 1968, the move away from domestic coal burning for home heating and the centralisation of electricity generation in large power stations away from towns and cities. Largely because of pollution emissions from motor traffic, urban air quality is once more causing public concern.

Air pollution has been associated with an increased incidence of respiratory disease. However, significant differences may exist between air pollution levels measured at conventional fixed monitoring stations and actual levels inhaled by a subject. Furthermore, studies of effects of air pollution might best be done using asthmatics as study subjects, since they have irritable airways. This is a preliminary report of a study using a control and asthmatic group in which effects of air pollution are assessed by symptom and medication diaries and simple pulmonary function tests.

Vehicle emissions depend directly on urban driving patterns which are an integral part of a wider range of urban features including density of settlement, car ownership, status of public transport, etc. Thus the conditions vehicles experience and their consequent emissions are directly related to the urban fabric. A methodology of sampling an urban area is developed by defining homogeneous areas within the city in terms of their activity intensity, modal split and social/economic status.

The purpose of the study is to evaluate the influence of an urban road tunnel in the atmosphere of contiguous working premises. Biological monitoring (COHb) on maintenance staff is added. Tunnel pollution levels are strongly correlated with the traffic intensity and influence the air quality of technical rooms in the same way as COHb concentration of employees.

Urban air quality makes headline news, and a recent Royal Commission report has stepped up the campaign against pollution from road vehicles. Better detection methods and monitoring mean that we are learning more about the air that we breathe.

In the poorer countries of the world, where energy consumption per capita is lower than in the industrialized nations, the process of rapid urbanization is a strong feature of the dynamic of economic development. Population growth rates in cities are consistently higher than in the countryside, due both to higher natural increases and to net migration. Although the majority ·of Asia's population is still rural, this dominance is expected to shift sometime around the tum of the century.