Diurnal variations of air pollution from motor vehicles in residential area

This paper employs the air quality data assembled by the Kuwait University mobile air pollution monitoring laboratory (Chemical Engineering Department). The experimental work has been conducted in the urban atmosphere of Khaldiya residential area in Kuwait University during 1997. The site was selected to represent a typical residential area which is mainly under high traffic influences. The data collected consist mainly of measurements of carbon monoxide (CO), nitrogen oxides (NO_x), non-methane hydrocarbon (NMHC) and Ozone (O₃). It is important to determine the behavior of these pollutants relative to meteorological parameters. Wind speed and direction were monitored simultaneously. The first objective of this paper is to measure the atmospheric levels of these pollutants and then compare their values with the international standard limits for an urban area. The second objective is to understand the diurnal and monthly variations of these pollutants. The third objective is to study the distribution levels of these pollutants with respect to meteorological parameters such as wind speed and direction. The results showed that the levels of NMHC and NO_x exceeded the proposed ambient air quality standard for residential areas in Kuwait The monthly mean distributions of NMHC, CO and NO_x showed distinct patterns with the lower concentrations during the summer period (July and August). The distribution of O₃ was different from the other gases. The maximum was seen in July and August. The hourly mean distribution of pollutants reported two types of concentration variations. The hourly mean distribution of NMHC, CO and NO_x were generally characterized by three peaks which were associated with the traffic loads on the main streets. On the other hand, the variation corresponding to O₃ revealed the occurrence of two daily maxima. The main distribution of the various pollutants according to wind speed indicated a marked drop with stronger winds and this was common to NMHC, CO and NO_x. The mean O₃ level with the wind speed showed an opposite picture.