Appendix 7 

Acute Impacts Refined Analysis Figures
Refined Acute Modeling Approach

Initial acute screening risk calculations were performed with the HEM-3 model. 

HEM-3 estimates acute (1-hour) impacts at both polar and census block receptors. It is 

assumed for this short period of time that an exposed individual could be located at any 

off-site location. The lack of readily available detailed property boundary information 

for many of the facilities evaluated made it difficult to determine whether receptors were 

on- or off-site. In the absence of such information, the first ring of polar receptors was 

placed 100 meters from the plant center for many facilities. However, these polar rings 

often transected on-site locations, restricting public access to exposures at these levels 

and thereby overestimating exposures.

The screening approach used by HEM-3 to estimate maximum 1-hour exposures 

also likely overestimates. To estimate maximum 1-hour concentrations at each receptor, 

HEM-3 sums the maximum concentrations attributed to each source, regardless of

whether those maximum concentrations occurred during the same hour. In other words, 

HEM-3 assumes that the maximum impact from each source at each receptor occurs at 

the same time. In actuality, maximum impacts from different sources may occur at 

different times.

This appendix addresses refinements to determine the maximum offsite values by

plotting the HEM-3 polar grid results on aerial photographs of the facilities. These 

photographs were examined to determine off-site locations that may be accessible to the 

public (e.g., roadways and public buildings.). The attached figures present the estimated

hazard quotient values (the modeled 1-hour concentration of a pollutant divided by its

short-term health benchmark) at the polar receptors near the facilities. 
Mineral Wool Production Mineral Wool Production

• Figure 1 - NEI32636 ; maximum 

offsite acute HQ for formaldehye of 

20 to the north of 20 to the north of the facility the facility
Figure 1 - NEI32636 Acute Formaldehyde HQ (REL)
Wool Fiberglass 

Man fact ring Manufacturing

• Figure 2- NEI32855 ; maximum offsite 

acute HQ for formaldehye of 30 (REL) to acute HQ for formaldehye of 30 (REL) to

the northeast of the facility

• Figure 3- NEI120375 ; maximum offsite 

acute HQ for formaldehye of 11 to the acute HQ for formaldehye of 11 to the

northwest of the facility

• Figure 4 – NEI11393; maximum offsite 

acute HQ for formaldehye of 6 to the acute HQ for formaldehye of 6 to the

north of the facility

• Figure 5 – NEIGA1210021; maximum 

off it t HQ f f ld h f 3 t ffsite acute HQ for formaldehye of 3 to 

the north and east of the facility

• Figure 6 – NEI11202; maximum offsite 

acut HQ f f ld h f 3 t th te HQ for formaldehye of 3 to the 

south and west of the facility

• Figure 7 NEI11431; maximum offsite 

acute HQ for formaldehye of 3 to the 

nprth and west of the facility
Figure 2 – NEI32855 Acute Formaldehyde HQ (REL)
Figure 3 – NEI12037 Acute Formaldehyde HQ (REL)
Figure 4 – NEI11393 Acute Formaldehyde HQ (REL)
Figure 5 – NEIGA1210021 Acute Formaldehyde HQ (REL)
Figure 6 – NEI11202 Acute Formaldehyde HQ (REL)
Figure 7 – NEI11431Acute Formaldehyde HQ (REL)