Appendix 7

Dispersion Model Receptor Revisions and Additions for Pulp and Paper
Dispersion Model Receptor Revisions and Additions for the Seven Chemical Sector 

Source Categories

To estimate ambient concentrations for evaluating long-term exposures, the HEM-3 

model uses the geographic centroids of census blocks (currently utilizing the 2000 Census) as 

dispersion model receptors. The census block centroids are generally good surrogates for where 

people live within a census block. A census block generally encompasses about 40 people or 10-

15 households. However, in cases where a block centroid is located on industrial property, or 

where a census block is large and the centroid less likely to be representative of the block’s 

residential locations, the block centroid may not be an appropriate surrogate.

Census block centroids that are on facility property can sometimes be identified by their 

proximity to emission sources. In cases where a census block centroid was within 300 meters of 

any emission source, we viewed aerial images of the facility to determine whether the block 

centroid was likely located on facility property. The selection of the 300-meter distance reflects a 

compromise between too few and too many blocks identified as being potentially on facility 

property. Distances smaller than 300 meters would identify only block centroids near the 

emission sources and could exclude some block centroids that are still within facility boundaries, 

particularly for large facilities. Distances significantly larger than 300 meters would identify 

many block centroids that are outside facility boundaries, particularly for small facilities. Where 

we confirmed a block centroid on facility property, we moved the block centroid to a location 

that best represents the residential locations in the block.

In addition, census block centroids for blocks with large areas may not be representative 

of residential locations. Risk estimates based on such centroids can be understated if there are 

residences nearer to a facility than the centroid, and overstated if the residences are farther from 

the facility than the centroid. To avoid understating the maximum individual risk associated 

with a facility, in some cases we relocated block centroids, or added dispersion model receptors 

other than the block centroid. We examined aerial images of all large census blocks within one

kilometer of any emission source. Experience from previous risks characterizations show that in 

most cases the MIR is generally located within 1 km of the facility boundary. If the block 

centroid did not represent the residential locations, we relocated it to better represent them. If 

residential locations could not be represented by a single receptor (that is, the residences were

spread out over the block), we added additional receptors for residences nearer to the facility 

than the centroid. 

For these source categories, the table below contains each census block for which we 

changed the centroid location because it was on facility property or was otherwise not 

representative of the residential locations in the block. The table also contains the locations of 

additional receptors that were included to represent residential locations nearer to the facility 

than the block centroid.
Revised Census Block Centroid Locations and Additional Receptors 

for Pulp and Paper Source Category

Centroid Revisions

Recommended Corr.

Source Category NEI ID

HEM Census 

Block Latitude Longitude Note

Pulp and Paper 

(MACT 1 and 3) NEI8196 031270007006006 31.193187 -81.506957

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI26309

120330037002000 30.610445 -87.321823 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI26309

120330037002004 30.605553 -87.329065 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI8261 120890501001014 30.688076 -81.456573

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI8261 120890501001035 30.677285 -81.458327

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI8265

121079501002098 29.71139 -81.71614 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI8265

121079501002102 29.708550 -81.716600 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI47091 121239504001252 30.054765 -83.530415

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEIIL0215971

170219585001011 39.55270 -89.28170 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI46835

230299554001015 45.155561 -67.403942 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI33945 261019907002048 44.216462 -86.28748

HEM Centroid on-site 
Pulp and Paper 

(MACT 1 and 3) NEI12411 270719902002036 48.603817 -93.41346

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI12411 270719902007009 48.594318 -93.399499

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI11172 280779601002062 31.620888 -90.084459

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI34064 280870011001039 33.3701 -88.479896

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI34070

281499501002027 32.523733 -90.78031 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI39968 360910602001001

43.304061 -73.633324 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI39968 361130705002019

43.310451 -73.631706 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEINY5533400 361150890002065

43.099505 -73.458657 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI11600 390170008001024 39.405852 -84.564164

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI11602 390170128001000 39.51994 -84.38576

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI11461 390319913002001 40.278089 -81.866312

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI11610 390610054001006 39.160574 -84.422065

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEIWI45005 391650325006004 39.550672 -84.311252

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI40553 410099707004000 45.853760 -122.80624

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI45182 410390019032005

44.048273 -122.961822 HEM Centroid on-site 
Pulp and Paper 

(MACT 1 and 3) NEI40648 410710302022001 45.290885 -122.96266

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI40648 410710302022002 45.290955 -122.965094

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI7106 420130101022000 40.677876 -78.237306

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI40686

420479905003005 41.491699 -78.675082 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI43472 450310103001019 34.390166 -80.066199

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI41552

470719806002011 35.045417 -88.26225 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI12492 483610211001001 30.231333 -93.744831

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42211 510190303002000 37.533863 -79.358067

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI208 510853201001071 37.823909 -77.448832

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42254 511019503002007

37.549069 -76.813387 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42254 511019503002013

37.545667 -76.806142 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42254 511019503002059

37.532944 -76.79925 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42329 530099807001004 48.132684 -123.474666

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI46599 530110414003004 45.583321 -122.414535

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42357 530319505002012 48.092833 -122.808055

HEM Centroid on-site 
Pulp and Paper 

(MACT 1 and 3) NEI2WAT18798 530519702003167

48.31204 -117.28274 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42482 550090102011039 44.447553 -88.068801

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42689

550730010001021 44.885043 -89.632150 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI42689 550730012012041 44.787667 -89.690379

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI43202 550859714004020 45.638895 -89.424058

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI43207

550870120001000 44.270007 -88.29402 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEI43207

550870120001015 44.269413 -88.30436 HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEIWI7500086 550979611003006 44.520670 -89.584477

HEM Centroid on-site 

Pulp and Paper 

(MACT 1 and 3) NEIWI4710355 551390029001002 44.203319 -88.458409

HEM Centroid on-site 
Additional Receptors

Recommended Corr.

Source Category NEI ID Latitude Longitude Note

Pulp and Paper 12089NEI8261 30.687903 -81.45658 Add User Defined Receptor

Pulp and Paper 12089NEI8261 30.688298 -81.45261 Add User Defined Receptor

Pulp and Paper 12123NEI47091 30.046987 -83.539535 Add User Defined Receptor

Pulp and Paper 22011NEI7559 30.869429 -93.356629 Add User Defined Receptor

Pulp and Paper 22011NEI7559 30.860808 -93.383871 Add User Defined Receptor

Pulp and Paper 22011NEI7559 30.88408 -93.38334 Add User Defined Receptor

Pulp and Paper 23017NEI6273 44.552802 -70.536573 Add User Defined Receptor

Pulp and Paper 23019NEI33103 44.917033 -68.639405 Add User Defined Receptor

Pulp and Paper 23019NEI33103 44.91869 -68.640304 Add User Defined Receptor

Pulp and Paper 23019NEI33103 44.915477 -68.639984 Add User Defined Receptor

Pulp and Paper 24001NEI33135 39.47489 -79.05747 Add User Defined Receptor

Pulp and Paper 24001NEI33135 39.47384 -79.05795 Add User Defined Receptor

Pulp and Paper 27061NEI34030 47.22971 -93.53091 Add User Defined Receptor

Pulp and Paper 41009NEI40553 45.854133 -122.804377 Add User Defined Receptor

Pulp and Paper 41009NEI40553 45.855088 -122.80388 Add User Defined Receptor

Pulp and Paper 41039NEI45182 44.051448 -122.970113 Add User Defined Receptor

Pulp and Paper 41041NEI40600 41.6555 -123.932194 Add User Defined Receptor

Pulp and Paper 41041NEI40600 44.614793 -123.931106 Add User Defined Receptor

Pulp and Paper 48361NEI12492 30.226318 -93.738393 Add User Defined Receptor

Pulp and Paper 51019NEI42211 37.532709 -79.357766 Add User Defined Receptor

Pulp and Paper 51085NEI208 37.819036 -77.453027 Add User Defined Receptor

Pulp and Paper 51580NEI759 37.797843 -79.99079 Add User Defined Receptor

Pulp and Paper 53009NEI42329 48.130770 -123.470715 Add User Defined Receptor

Pulp and Paper 53011NEI46599 45.582800 -122.415091 Add User Defined Receptor

Pulp and Paper 53031NEI42357 48.090916 -122.804924 Add User Defined Receptor

Pulp and Paper 55073NEI42690 45.026841 -89.651652 Add User Defined Receptor

Pulp and Paper 55079NEIWI0793640 43.062013 -87.889484 Add User Defined Receptor

Pulp and Paper 55085NEI43202 45.638582 -89.421621 Add User Defined Receptor

Pulp and Paper 55085NEI43202 45.639874 -89.424034 Add User Defined Receptor

Pulp and Paper 55139NEIWI4710355 44.206271 -88.4559 Add User Defined Receptor

Pulp and Paper 39165NEW45005 39.555043 -84.304069 Add User Defined Receptor

Pulp and Paper 39165NEW45005 39.554643 -84.304651 Add User Defined Receptor