IFs uses PM 2.5 concentration in urban areas (ENVPM2PT5) as a proxy for outdoor air pollution. Outdoor air pollution impacts mortality related to respiratory infections, respiratory disease, and cardiovascular disease for adults 30 or older.

The distal driver formulation for ENVPM2PT5 uses the following formula:

In the above equation GDPPCP is GDP per capita at purchasing power parity and EDYRSAG25 is average years of formal education for adults over 25.

The full driver formulation for ENVPM2PT5 uses the following formula:

T is time expressed as the current year

GDSHealth%GDP is the government expenditures in health as a percentage of GDP

The first formula returns PM10 concentration levels which then are converted to PM2.5 using a conversion factor. The WHO (Ostro 2004 and EBD spreadsheet) recommends the following conversion factors:

• 0.5 - developing countries outside of Europe
• 0.65 - developed countries outside of Europe
• 0.73  - European countries

In the case of outdoor air pollution we can assume that all persons in urban areas are exposed to the same level of air pollution and therefore the same relative risk. Therefore we can simplify the mortality effect as follows:

where the recommended value for β is 0.1161. ^[1]