Air emissions facilities are clustered in and around the Providence metropolitan area. Within the City of Providence, the Washington Park and Lower South Providence neighborhoods are exposed to a higher level of toxic air emissions than are other areas of the city. This was determined by mapping facilities listed in the RI Air Emissions Inventory (AEI), modeling their emissions with the SCREEN3 air dispersion model, and incorporating toxicity data for chemicals listed in the inventory. (See this study's risk versus DEM's risk)

Within Washington Park, the neighborhoods closest to the Narragansett Bay Commission's (NBC) Field's Point Sewage Sludge Incinerator bear the most significant burden from air toxic emissions. Emissions from smaller facilities, when located close together, can cumulatively be important, but singularly each small facility's emissions are insignificant. In the study area, small area sources did not significantly impact the surrounding neighborhoods. Washington Park and Lower South Providence's facility emissions expose not only the study neighborhoods, but also areas outside the study area (in Providence), and outside the city (East Providence, Cranston, Warwick). Facilities in those cities may also have emissions extending to our study area, ultimately increasing risk. This is one example of why intercity cumulative exposures must be addressed in future studies.