Atmospheric Environment 34 (2000) 4727}4736 Oslo tra$c study } part 1: an integrated approach to assess the combined e!ects of noise and air pollution on annoyance R. Klvboe*, M. Kolbenstvedt, J. Clench-Aas, A. Bartonova Institute of Transport Economics, P.O. Box 6110, N-0602 Oslo, Norway Norwegian Institute for Air Research, P.O. Box 100, N-2027 Kjeller, Norway Received 20 September 1999; accepted 16 June 2000 Abstract Vehicular tra$c is a common important source of air pollution, tra$c accidents, road tra$c noise as well as other environmental exposures. The relationship between each of these exposures and their respective impacts are nevertheless most often studied separately. An integrated alternative approach was adopted in the Oslo tra$c study to allow people's environmental annoyances to be studied relative to the indicators of air pollution, road tra$c noise and residential tra$c. These annoyances include annoyance with the smell of exhaust, with dust and grime, feeling insecure in tra$c and being annoyed with road tra$c noise. A hypothesis was that multiple exposures typical in city areas have combined impacts } that people exposed to both air pollution and road tra$c noise will be more annoyed than in the respective single-exposure situations. Three environmental studies in 1987, 1994 and 1996 each year comprising about 1000 respondents after a response rate of 50%, serve as before}after studies of two tunnel projects. Personal interviews were utilised in the before study in 1987 and telephone interviews in 1994 and 1996. Exposure indicators for air pollution as well as road tra$c noise and residential tra$c levels were produced for each respondent by comprehensive environ- mental modelling. Exposure}e!ect logistic regression models for the probability of people being highly annoyed by the smell of exhaust and by road tra$c noise, respectively, were estimated. The results indicate that the higher the road tra$c noise levels people are exposed to, the more likely they are to be highly annoyed by exhaust smell at a speci"ed air pollution level. The higher air pollution levels people are exposed to the more likely they are to be annoyed by road tra$c noise at a speci"ed noise level. Modifying factors were controlled for.  2000 Elsevier Science Ltd. All rights reserved. Keywords: Environmental surveys; Road tra$c noise; Air pollution; Annoyance; Tra$c measures 1. Introduction In addition to road tra$c noise, insecurity and sever- ance, an increasing number of studies are inquiring into the perception, annoyance, coping behaviour and subjec- tive health e!ects of air pollution (Evans et al., 1988; Forsberg et al., 1993, 1997a; Kolbenstvedt et al., 2000; Lercher and Ko#er, 1996; Lercher, 1996; Williams et al., 1992; Winneke et al., 1996). A common aspect of these studies is that dust/grime and the smell of exhaust can be perceived (Forsberg et al., 1997b), a!ect behaviour, and * Corresponding author. E-mail address: ronny.klaboe@toi.no (R. Klvboe). cause problems at levels well below current air pollu- tion limits and at levels often associated with urban tra$c. Most often annoyance reactions are studied with re- spect to each environmental exposure separately without taking other environmental exposures into account. However, air pollution, road tra$c noise and insecurity might all be regarded as ambient stressors (Campbell, 1983) that can have combined impacts. This paper inves- tigates whether there are combined e!ects of air pollution and road tra$c noise on annoyance with the smell of exhaust and with road tra$c noise, respectively. Are people exposed to higher levels of road tra$c noise more inclined to be annoyed with air pollution than those exposed to lower levels? Vice versa, are people exposed to 1352-2310/00/$ - see front matter  2000 Elsevier Science Ltd. All rights reserved. PII: S 1 3 5 2 - 2 3 1 0 ( 0 0 ) 0 0 3 0 4 - 6