Since road traffic is a source of both air pollutants and noise, it is very important to disentangle the health effects of the two very different types of environmental exposures related to road traffic. There are indications that both noise and air pollu tion are associated with increased risk of cardiovascular disease. No studies have been published thus far that have systematically taken both factors into account. If environmental effects on cardiovascular morbidity and mortality are primarily related t o noise, abatement measures directed against air pollutants could only have a limited effect. If on the other hand, effects are primarily related to air pollutants, abatement measures directed at noise reduction could conversely have little impact. This p roject proposal outlines a study to be conducted in four European countries (UK, Sweden, The Netherlands and Norway) in the framework of ongoing studies. The Norwegian contribution will combine data on noise exposure and air pollution exposure with data f rom two large health effect studies of individuals living in Oslo. The Oslo I study is a follow-up study initiated in 1972-73 consisting of 16 206 males. The Oslo Health Study (HUBRO) was conducted in 2000-2001, and consists of more than 18 000 females an d males, enabling also the study of possible gender differences. The relationship between noise, air pollution and self reported health status, cardiovascular risk factors, and premature mortality will be analysed. These investigations on the combined ef fects of the two stressors, as well as the independent role of each, should provide important new information and policy relevant data with potentially great public health consequences.