Survey of carbon monoxide concentrations in selected urban microenvironments.

Carbon monoxide concentrations were measured in six shops situated in narrow busy streets of the city centre for ten days in winter and ten days in summer and correlated with the measurements simultaneaously performed at an outdoor background reference point. The correlation was significant for four out of six shops in winter, but not in summer. Day-to-day variations seemed to be influenced by gross contamination due to changing weather conditions whereas differences in concentration levels from site to site were strongly influenced by the proximity and density of traffic. The exposure of a pedestrian in winter was in good correlation with background outdoor levels and it was considerably lower than that of a car driver driving though the city.