The contribution of nonroad equipment to overall risk is substantially lower in the 2002 national-scale assessment than it was in 1996. Is this due to changes in methodology or real reductions?
There are a number of factors contributing to these reductions. These include several methodological changes. • EPA used the Integrated Risk Information System (IRIS) cancer potency estimate for formaldehyde which is several orders of magnitude higher than the CIIT-based value used in the 1999 and 2002 assessments. • There were improvements in data and methods used to develop nonroad air toxics inventories since the 1996 assessment was conducted. These data changes result in larger reductions in emissions for several key pollutants, but may not reflect actual emission reductions. • There were changes in how emissions were spatially allocated for several types of nonroad equipment. Some emissions were re-located in lower populated areas resulting in lower exposure and risk estimates. These coupled with actual improvements in nonroad emissions since the 1996 assessment, contribute to the overall reductions seen.
Related Questions
- The contribution of nonroad equipment to overall risk is substantially lower in the 1999 national-scale assessment than it was in 1996. Is this due to changes in methodology or real reductions?
- WHAT CAN AN INMATE DO IF THE PAROLE BOARD WANTS HIM/HER IN A LOWER SECURITY BUT THE RISK ASSESSMENT SCORE IS TOO HIGH TO BE CLASSIFIED AS SUCH?
- Based on this national-scale assessment, can EPA determine which areas and/or populations are at greatest risk from air toxics?
