ABSTRACT
A particular problem is to relate “soot” measures of particle emissions to “Black Carbon” measures of ambient air aerosols. But light reflection depends on particle size and composition, and it is difficult to model the relation between emission and concentration in ambient air, as particle size and composition changes in a complex way. Particles differ in size, form and composition. The reason it is meaningful to classify them and link them to specific impacts is that most particles in ambient air originate from a limited number of sources and processes. The uncertainty for the impact factor of CO2’s impact on diarrhea was estimated to a factor of 3. The environmental impact factor will vary significantly depending on local conditions, such as population density and ventilation premises. Risk estimates for As relies on work environment observations, while the risk for PM2.5 is determined in cohort studies on large population groups.
