Very often, when there is noise there is air pollution and vice versa, air pollution from traffic (and for example building sites) goes hand in hand with noise.
An interesting Commentary in the January (yes, I am slightly behind with reading) 2011 issue of the journal Environmental Research (here) discusses the correlation between the two and their links to cardiovascular effects. So is it air pollution? or is it noise?
There is both evidence for a link between noise and increased risk for cardiovascular outcomes such as hypertension, myocardial infarction and ischemic heart disease, but there is also substantial scientific evidence linking (long term) air pollution to cardiovascular morbidity and mortality. Moreover, plausible biological mechanisms have been described for both exposures and evidence from related scientific disciplines such as toxicology and occupational epidemiology support independent cardiovascular health impacts of both exposures.
So what does this mean in practice? Obviously if you had the choice, living very close to a major road is not a very good idea; be it from the traffic-related pollution levels or from the noise (especially it seems, when you are easily annoyed). However, from an epidemiological perspective this argument suggests that there may be confounding between air pollution and noise. So when conducting these studies it seems like a good idea to include estimates of both and assess their independent effects as well as their interaction (how to actually obtain these estimates. preferably based on measurements (or “real” data) with as little misclassification as possible is a different issue and may be the topic of a future post)…
Sense about Science
The Fun Police 
Ian Bennett
June 14, 2011
The science is rather lost under the impact of poor Mellissa (photo) who is apparently worried about the effects of noise of jack hammers on her unborn child – so worried in fact that she is still smoking! Love her to bits!. There may be an over lap, but is there a full correlation, noisy processes do not always emit pollution and polluters can sometimes be SBD- Silent But Deadly!
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FdV
June 14, 2011
I agree, and luckily there is not a 100% correlation. Those sites where there is no, or only a very small correlation (combined with single exposure laboratory studies) may well provide the key to disentangling these “competing risks”.
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