The World Health Organization (WHO), today classified diesel engine exhaust as carcinogenic to humans
http://www.iarc.fr/en/media-centre/iarcnews/2012/mono105-info.php
The main takeaway is that:
-- the WHO is unanimously saying there is no longer any doubt.
--that the results shown in the higher risk/dosage tests on miners will be born out in the general population
--that even diesel released from new higher standard emission sources needs research to determine how dangerous it is
And before you can say "Tier 4 Clean Diesel" read this: " However, while the amount of particulates and chemicals are reduced with these changes, it is not yet clear how the quantitative and qualitative changes may translate into altered health effects; research into this question is needed.
Build the Airport Link right the first time: Go Electric !