vehicle emissions

Describes an assessment using carbon monoxide and volatile organic compounds as IAQ indicators for indoor air quality in a representative underground parking facility. Measurements were made at different time intervals throughout the day. The EMFAC7F1.1 model was used to estimate vehicular emission factors. Concentration profiles were then assembled using a transient mass balance model.

All internal combustion engines produce exhaust gases containing noxious compounds: carbon monoxide (CO), nitrogen oxides (NOx, carbon oxides (CxHy) and smoke. With the help of a mathematical model the concentrations of some dangerous substances at the end of the tunnel were calculated, and were replaced by a criteria! number. A corresponding computer program was also developed thus enabling quick and simple calculations of some concentrations and the criteria! number.

This paper examines three different ventilation strategies aimed at reducing the indoor concentration of traffic pollutants by ventilation control. In the strategies the air change rate is adjusted in response to (a) the outdoor concentration of the pollutant (single-sensor strategy), (b) the outdoor and indoor concentration (double-sensor strategy) and (c) the time of the day (peak-period strategy). A double sensor was found to be twice as effective as the single sensor, reducing the mean indoor concentration of carbon monoxide by 34% over a 48-hour period.

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.