The effect of urban air - ambient Munich air - on aphid growth was investigated. Rose bushes (Rosa sp., cv. Nina Weibull) were fumigated with either ambient Munich air or charcoal-filtered air. Then the plants were infected with aphid Macrosiphon rosae nymphs. The mean relative growth rate of aphids feedings on roses in ambient air was about 20% higher than those feeding in the filtered atmosphere. This result confirms previous studies that air pollution enhances the pest potential of aphids.