Health and Environment
In this 2012, reasearchers compared the concentrations of ultrafine particles in emissions coming from Waste-to-Energy plants, vehicular traffic, wood combustion boilers, oil combustion boilers, natural gas combustion. They also assessed these concentrations in comparison to ambient air.
“For all [Waste-to-Energy] plants studied, the concentrations measured are consistently lower by at least two orders of magnitude compared with those found for wood and oil combustion in domestic boilers, and only slightly higher than those produced by natural gas boilers;” p. 30
An English summary can be found here.
Reference: S. Cernuschi, S. Consonni and M. Giugliano, Emissioni di Polveri Fini e Ultrafini da impianti di combustione, Politecnico di Milano, 2012.