Given below in sober scientific language is the outcome of decades of deliberation:
After a week-long meeting of international experts, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), today classified diesel engine exhaust as carcinogenic to humans (Group 1), based on sufficient evidence that exposure is associated with an increased risk for lung cancer.
The New York Times explains that the implications are more serious for people in developing countries :
The W.H.O. decision, the first to elevate diesel to the “known carcinogen” level, may eventually affect some American workers who are heavily exposed to exhaust. It is particularly relevant to poor countries, where trucks, generators, and farm and factory machinery routinely belch clouds of sooty smoke and fill the air with sulfurous particulates.
Second hand smoke is considered less dangerous, but just yesterday I wrote that it is significant negative externality that should be discouraged through taxation.
Electro magnetic radiation from mobile handsets and towers is even less dangerous according to the WHO:
Based largely on these data, IARC has classified radiofrequency electromagnetic fields as possibly carcinogenic to humans (Group 2B), a category used when a causal association is considered credible, but when chance, bias or confounding cannot be ruled out with reasonable confidence.
So in sum, electromagnetic radiation from mobiles is less dangerous than second-hand smoke, which is less dangerous than diesel fumes.
What do we worry about the most? What is dissuaded by punitive taxes?