The benefits of reducing 1 ton of air pollution

The influence of location, source, and emission type in estimates of the human health benefits of reducing a ton of air pollution (8 page pdf)

Key Quotes

"The benefit per ton ($/ton) of reducing PM2.5 varies by the location of the emission reduction, the type of source emitting the precursor, and the specific precursor controlled. This paper examines how each of these factors influences the magnitude of the $/ton estimate."

"This heterogeneity is a product of source location, meteorology, mix of pollutants emitted, and atmospheric conditions, including baseline atmospheric concentrations of pollutants."

"Three inter-related sources of heterogeneity affect the magnitude of PM2.5 $/ton estimates.

The first relates to the chemical processes that govern the formation of PM2.5 in the atmosphere....

The second source of heterogeneity relates to the characteristics of the emitting source...

The third factor that may influence the heterogeneity in PM2.5-related $/ton estimates is the size of the population exposed to PM2.5 and the susceptibility of that population to adverse health outcomes."

"It should be noted that, while NOx reductions may occasionally generate PM2.5 disbenefits in certain urban areas, because NOx is also an O3 precursor, additional NOx reductions—even in areas where PM2.5 disbenefits are possible—may produce a downwind O3 benefit."

"The PM2.5 $/ton estimates in this paper reflect three principal sources of heterogeneity:

Variability across precursors. The $/ton for certain pollutants, such as directly emitted PM2.5, is much higher than others...

Variability across sources. Certain sources may emit a common precursor, but may produce very different $/ ton estimates...

Variability across location. The $/ton for a given pollutant showed some degree of variation based on the urban area in which the pollutant was emitted."