HomeMy WebLinkAboutAppendix H - Screening Level Health Risk Assessment❖ APPENDICES ❖
7106/Summit Avenue Warehouse Project
Initial Study/Mitigated Negative Declaration May 2022
APPENDIX H
Screening Level Health Risk Assessment
Corporate Office – Orange County Telephone: 949.788.4900
16431 Scientific Way Facsimile: 949.788.4901
Irvine, CA 92618-4355 Website: www.ultrasystems.com
MEMO
TO: Bobby Allard, Allard Engineering
FROM: Michael B. Rogozen, D. Env.
DATE: April 19, 2022
PROJECT #: 7106
RE: Screening Air Toxics Health Risk Assessment for the Summit Avenue Warehouse
Project, Fontana, California
This screening health risk assessment (HRA) was conducted in support of an Initial Study/Mitigated
Negative Declaration (IS/MND) prepared under the California Environmental Quality Act (CEQA). It
covers a proposed warehouse facility at Sierra Avenue and Summit Avenue, in Fontana, California.
The project site is adjacent to industrial uses on the north, east and south; and residential
developments on the west and southwest. The facility will be visited at all hours of the day by diesel
trucks. As the California Air Resources Board (ARB) has formally designated particulate emissions
from diesel engines as a toxic air contaminant (TAC),1 this screening HRA focuses on diesel
particulate matter (DPM) emissions from project construction equipment and from diesel trucks
used in freight service.
The purpose of this screening HRA was to address partially question III.c of the CEQA Guidelines:
“Would the project expose sensitive receptors to substantial pollutant concentrations?” Exposure of
sensitive receptors to criteria pollutants is discussed in Section 4.3.6 of the IS/MND. This screening
HRA expands the discussion to exposure to diesel exhaust. HRAs frequently cover cancer and
noncancer health risks. As will be discussed below, this analysis was limited to cancer risk. The
objective was to determine whether the increase in maximum individual cancer risk (MICR) would
exceed the CEQA significance threshold established by the South Coast Air Quality Management
District (SCAQMD). That threshold is a risk increase of 10 in one million (10 x 10-6).2 The main
differences between this screening analysis and a full HRA is that it uses simplified “worst-case”
assumptions about meteorology in modeling atmospheric dispersion of project emissions. Generally,
this approach results in higher risk estimates than those using more detailed information about
1 The Toxic Air Contaminant Identification Process: Toxic Air Contaminant Emissions from Diesel-fueled Engines. Fact
Sheet. California Air Resources Board, Sacramento, CA. October 1998.
https://www.arb.ca.gov/toxics/dieseltac/factsht1.pdf.
2 SCAQMD Air Quality Significance Thresholds. South Coast Air Quality Management District. April 2019.
http://www.aqmd.gov/docs/default-source/ceqa/handbook/scaqmd-air-quality-significance-
thresholds.pdf?sfvrsn=2.
Health Risk Assessment
7106/Summit Avenue Warehouse Project Page 2
Screening Health Risk Assessment April 2022
emissions and meteorology. If the screening analysis shows that risk would be less than significant,
then more detailed modeling is not necessary.
The project applicant proposes to construct and operate an approximately 102,380-square-foot
warehouse building and related uses on approximately 4.49 gross acres of land at the northeast
corner of Summit Avenue and Sierra Avenue in Fontana, California (APN 0239-161-28). The project
would consist of 92,380 square feet of warehousing space, 5,000 square feet of office space on first
floor, 5,000 square feet of office space on a mezzanine floor, 11 dock-high doors, 3 trailer stalls, and
53 automobile parking stalls. Landscape improvements are also proposed onsite. Utility connections
to water, sewer, and electricity would be constructed.
Primary site ingress and egress would be provided by a 30-foot-wide driveway along the
northwestern edge of the project site along Sierra Avenue. The proposed project would include 11
dock doors and three trailer stalls in compliance with the City’s requirements. There would be 53
automobile parking stalls that would consist of three American Disabilities Act (ADA) stalls and 50
regular parking stalls in the northern portion of the project site. Circulation within the site would be
along the 26-foot-wide fire lane inside the northern and southern perimeters of the project site, and
a 30-foot-wide fire lane inside the eastern perimeter of the project site. The number of truck trips
per day is estimated to be 53.3
The HRA generally followed procedures prescribed by the SCAQMD for analyzing cancer risks from
mobile source diesel idling emissions.4 Although “Idling” is in the title, the guidance covers emissions
from truck traffic on local streets and/or arterials, onsite truck movement, and onsite truck idling.5
Given that construction equipment operates onsite and moves from place to place, it is similar in
nature to onsite truck movement and idling, and was therefore analyzed in accordance with the
SCAQMD guidance. The analysis consisted of three steps:
Estimation of emissions;
Dispersion modeling to calculate ground-level concentrations of diesel particulate matter
(DPM) in the vicinity of the site; and
Calculation of individual cancer risk.
Additional guidance was obtained from a review of a recent HRA in the project area6 and from
SCAQMD comments on health risk assessments reported in various CEQA documents.
3 See Attachment 1.
4 Health Risk Assessment Guidance for Analyzing Cancer Risks from Mobile Source Idling Emissions for CEQA Air Quality
Analysis. South Coast Air Quality Management District, Diamond Bar, CA. August 2003.
5 The guidance also includes transportation refrigeration units and auxiliary power units, but those devices were
assumed not to be included in the proposed project.
6 Air Quality, Health Risk, and Greenhouse Gas Analysis Report. Santa Ana Avenue and Citrus Avenue Warehouse Project.
City of Fontana, San Bernardino County, California. Prepared by First Carbon Solutions, San Bernardino, CA for Seefried
Industrial Properties, Inc., Phoenix, AZ. January 6, 2016.
Health Risk Assessment
7106/Summit Avenue Warehouse Project Page 3
Screening Health Risk Assessment April 2022
Note that for this screening assessment, emissions and exposures along local roadways were not
analyzed. UltraSystems’ experience in preparing full HRAs for two warehouses in Fontana found that
the roadway exposure contributes a minor amount (about 4%) of the total risk.
Following ARB guidance,7 the analysis used particulate matter with an aerodynamic diameter less
than 10 micrometers (PM10) to represent DPM. This is a conservative approach, since about 90% of
DPM emissions are actually less than 2.5 micrometers (PM2.5),8 and PM2.5 emissions are always less
than or equal to those of PM10.
Construction Emissions
Onsite PM10 emissions during construction were obtained from the CalEEMod analysis conducted
for the air quality and greenhouse gas emissions report prepared for the project.9 A time-weighted
average daily PM10 emission rate was calculated as shown in Table 3.2‐1.
Table 3.2‐1
TIME‐WEIGHTED DPM EMISSIONS DURING CONSTRUCTION
Activity and Year Days
PM10
Emissions
(lb/day)
Product
Site Preparation (2022) 3 0.5952 1.7856
Grading (2022) 6 0.7423 4.4538
Building Construction (2022) 122 0.7022 85.6684
Building Construction (2023) 18 0.6136 11.0448
Paving (2023) 10 0.4338 4.338
Painting (2023) 10 0.0708 0.708
Totals 169 107.9986
Time‐Weighted Average (lb/day)0.6390
Number of Daily Diesel Trucks
For a similar project, the SCAQMD recommended a total vehicle daily trip rate of 1.68 vehicles per
thousand square feet of warehouse space.10 For the Sierra Avenue and Summit Avenue project, the
total heavy-duty vehicle (gasoline plus diesel) trip rate would be 59. The HRA considered three
categories of freight trucks: light heavy duty, medium heavy duty, and heavy-heavy duty. Table 3.2‐
2 shows their definitions and percentages of the total traffic generated.
7 HARP Users Guide. Appendix K. Risk Assessment Procedures to Evaluate Particulate Emissions from Diesel-Fueled
Engines. California Air Resources Board. 2003. https://www.arb.ca.gov/toxics/harp/docs/userguide/appendixK.pdf.
8 Overview: Diesel Exhaust and Health. California Air Resources Board. April 12, 2016.
https://www.arb.ca.gov/research/diesel/diesel-health.htm.
9 Air Quality and Greenhouse Gas Emissions Report for the Summit Avenue Warehouse Project, Fontana, California.
Prepared by UltraSystems Environmental Inc. for the City of Fontana, California. April 2022.
10 Letter from Jillian Wong, Planning and Rules Manager, South Coast Air Quality Management District, Diamond Bar, CA
to Nikki Cavazos, Assistant Planner, City of Rancho Cucamonga, CA re Mitigated Negative Declaration (MND) for the
Proposed Hickory Warehouse. January 27, 2017.
Health Risk Assessment
7106/Summit Avenue Warehouse Project Page 4
Screening Health Risk Assessment April 2022
Table 3.2‐2
DEFINITIONS OF TRUCK CATEGORIES
Category Axles EMFAC2014
Class
Fraction of
Total Vehiclesa
No. Trucks per
Day
Light 2 LHD1 & LHD2 0.0645 10.0
Medium 3 MHDT 0.0865 13.4
Heavy 4 or more HHDT 0.23 35.7
aFractions of total vehicles are from Air Quality, Health Risk, and Greenhouse Gas Analysis Report. Santa Ana Avenue and
Citrus Avenue Warehouse Project. City of Fontana, San Bernardino County, California. Prepared by First Carbon Solutions,
San Bernardino, CA for Seefried Industrial Properties, Inc., Phoenix, AZ. January 6, 2017.
The diesel-fueled percentages of the light-, medium- and heavy-heavy duty trucks were assumed to
be 57.8%, 86.7%, and 99.1%, respectively.11 As a result, the total number of diesel trucks traveling
to and from the facility was estimated to be 53.
Scheduling
For modeling purposes, it was assumed that each of the 53 trucks per day would arrive on site, go to
a loading dock, be unloaded and/or loaded, and depart from the site. The 53 trip cycles were
distributed fairly evenly through the day. For each hour of the day the number of trucks in each of
the activities was estimated.
Emission Factors
For trucks in motion (traveling on the project site), emission factors (in grams per mile) were
obtained from the ARB’s EMFAC 2021 Web Database.12 The onsite vehicle speed was assumed to be
5 miles per hour. Emission factors for each truck class were obtained for 2024 through 2050 and
then averaged. Table 3.2‐3 summarizes the emission factor data.
Table 3.2‐3
DIESEL TRUCK EMISSION FACTORS
Vehicle Class Emissions (g/mile)
Onsite (5 mph)
Light Heavy Duty 0.0347
Medium Heavy Duty 0.0333
Heavy-Heavy Duty 0.0344
Idling emissions for the light-, medium- and heavy-heavy duty trucks were 0.472, 0.018, and
0.004 grams per idle hour, respectively.13 Trucks were assumed to idle for 15 minutes per hour, so
each of these rates was divided by four. Emissions while the trucks are moving were estimated by
multiplying the emission factors by vehicle miles traveled on the project site. The emission rates
11 Air Quality, Health Risk, and Greenhouse Gas Analysis Report. Santa Ana Avenue and Citrus Avenue Warehouse Project.
City of Fontana, San Bernardino County, California. Prepared by First Carbon Solutions, San Bernardino, CA for Seefried
Industrial Properties, Inc., Phoenix, AZ. January 6, 2016.
12 https://arb.ca.gov/emfac/emissions-inventory/7284dfd42dba54cc28110fffd2480fdef0574559. Accessed December
8, 2021.
13 Air Quality, Health Risk, and Greenhouse Gas Analysis Report. Santa Ana Avenue and Citrus Avenue Warehouse Project.
City of Fontana, San Bernardino County, California. Prepared by First Carbon Solutions, San Bernardino, CA for Seefried
Industrial Properties, Inc., Phoenix, AZ. January 6, 2016.
Health Risk Assessment
7106/Summit Avenue Warehouse Project Page 5
Screening Health Risk Assessment April 2022
were converted to the units needed by the dispersion model, which are grams per second per square
meter. (See Section 3.3.1.)
The U.S. Environmental Protection Agency’s screening dispersion model SCREEN314 was used for the
dispersion modeling.
Sources
Construction activities were modeled as one combined volume source whose footprint was the same
as the entire project site.15 Onsite truck activities (onsite travel and idling) were defined as “area
sources,” the area being the entire site.
Receptor Grid
SCREEN3 was run for pollutant travel only directly west from the project site, since all of the sensitive
receptors are in that direction. The model calculated concentrations at every 100 meters from the
center of the project site, out to 500 meters. It also calculated them at the site boundary (90 meters
from the site center), at the nearest residence (at 139 meters) and at a point that it determined to
have the maximum concentration (see below).
Meteorology
The model was set to determine the combination of meteorological variables (wind speed, stability
class, mixing height, etc.) that yielded the maximum predicted pollutant concentration.
Adjustment to Annual Emissions
The SCREEN3 model estimates 1-hour average concentrations in air. For the health risk analysis,
average annual concentrations are needed. The U.S. Environmental Protection Agency has not
published factors for converting hourly average values to annual concentrations for area sources.
14 SCREEN3 Model User’s Guide. U.S. Environmental Protection Agency, Office of Aire Quality Planning and Standards,
Research Triangle Park, NC. EPA-454/B-95-004. September 1995.
https://gaftp.epa.gov/Air/aqmg/SCRAM/models/screening/screen3/screen3d.pdf. Accessed December 8, 2021.
15 Construction activities were also modeled as an area source, but the volume source alternative yielded a more
conservative (i.e., higher) exposure estimate.
Health Risk Assessment
7106/Summit Avenue Warehouse Project Page 6
Screening Health Risk Assessment April 2022
However, several state and regional agencies have recommended such factors,16,17,18,19 which range
from 0.05 to 0.1. For a maximum case, we used 0.1.
Health risk assessments for DPM usually address cancer and chronic noncancer risk. Acute
(short-term exposure) risk for DPM is not assessed because health risk data for acute exposure are
lacking. For the proposed project, chronic noncancer risk was not assessed because it is generally
much lower than its CEQA threshold than is the cancer risk from its threshold.20
Cancer risk was calculated from the following formula:21
CRDPM = CDPM * URFDPM * LEA
where:
CRDPM = Cancer risk from diesel particulate matter; the probability of an individual
developing cancer as a result of exposure to DPM.
CDPM = Annual average DPM concentration in micrograms per cubic meter
URFDPM = Unit risk factor for DPM; estimated probability that a person will contract cancer
as a result of inhalation of a DPM concentration of 1 microgram per cubic meter
continuously over a period of 70 years
LEA = Lifetime exposure adjustment
The unit risk factor for DPM is 3.0 x 10-4 per microgram per cubic meter, according to the Office of
Environmental Health Hazard Assessment.22 For operational exposure, LEA = 1. The LEA for
construction exposure was calculated by dividing the number of days of construction activity (169)
by the number of days in 70 years (25,550).
16 South Carolina Modeling Guidelines for Air Quality Permits. Department of Health and Environmental Control.
Revised April 15, 2019.
https://scdhec.gov/sites/default/files/media/document/BAQ_SC%20Modeling%20Guidelines_10.15.18_revised%2
04.15.19.pdf. Accessed December 8, 2021.
17 Oil and Gas Standard Permit and Permit by Rule Refined-Screening Modeling Guidelines. Texas Commission on
Environmental Quality. https://www.tceq.texas.gov/assets/public/permitting/air/Guidance/NewSourceReview/og-
mod-pro.pdf. Accessed December 8, 2021.
18 Recommended Methods for Screening and Modeling Local Risks and Hazards. Bay Area Air Quality Management
District, San Francisco, CA, Version 3.0, May 2012.
https://www.baaqmd.gov/~/media/Files/Planning%20and%20Research/CEQA/Risk%20Modeling%20Approach
%20May%202012.ashx?la=en. Accessed December 8, 2021.
19 Risk Assessment Procedures for Rules 1401 and 212, Version 7.0. South Coast Air Quality Management District,
Diamond Bar, CA. July 1, 2005. http://www.aqmd.gov/docs/default-source/planning/risk-assessment/risk-
assessment-procedures-v-7.pdf?sfvrsn=4. Accessed December 8, 2021.
20 The relative importance of DPM cancer risk and chronic noncancer risk is discussed in HARP Users Guide. Appendix K.
Risk Assessment Procedures to Evaluate Particulate Emissions from Diesel-Fueled Engines. California Air Resources
Board. 2003. https://www.arb.ca.gov/toxics/harp/docs/userguide/appendixK.pdf.
20 Overview: Diesel Exhaust and Health. California Air Resources Board. April 12, 2016.
https://www.arb.ca.gov/research/diesel/diesel-health.htm.
21 Health Risk Assessment Guidance for Analyzing Cancer Risks from Mobile Source Idling Emissions for CEQA Air
Quality Analysis. South Coast Air Quality Management District, Diamond Bar, CA. August 2003, pp 8-9.
22 Appendix A: Hot Spots Unit Risk and Cancer Potency Values. Office of Environmental Health Hazard Assessment.
Updated May 2019. https://oehha.ca.gov/media/CPFs042909.pdf. Accessed December 8, 2021.
Health Risk Assessment
7106/Summit Avenue Warehouse Project Page 7
Screening Health Risk Assessment April 2022
SCREEN3 modeling results are provided in Attachment 2.
During construction, the maximum annual average DPM concentration would be 0.272 μg/m3, at 100
meters from the center of the project site; this would be in the northbound roadway of Sierra Avenue.
The maximum concentration at a sensitive receptor would be 0.196 μg/m3, in the residential
neighborhood on the west side of Sierra Avenue.
During project operations, the maximum annual average DPM concentration would be 0.24
micrograms per cubic meter (μg/m3), at 120 meters from the center of the project site. This location
is in the roadway of Sierra Avenue. The maximum residential exposure would be at the nearest house
on the west side of Sierra Avenue; it would be 0.023 μg/m3.
Table 4.2‐1 summarizes the results of the modeling and risk calculation. The maximum residential
exposure is below the SCAQMD’s threshold. A more sophisticated analysis, using actual meteorology
for the area, would yield lower cancer risk estimates.
Table 4.2‐1
MAXIMUM INDIVIDUAL CANCER RISK RESULTS
Project Phase
Maximum Individual
Cancer Risk
(per million)
SCAQMD CEQA
Significance
Threshold
(per million)
Construction 0.39 10
Operations 6.9 10
As was noted previously, this analysis did not include chronic noncancer risk, since that type of risk
relative to its CEQA threshold would be even lower than the cancer risk is to the 10-in-one-million
threshold. Also, risk to workers in the surrounding area was not included because occupational
lifetime exposures would be less than those of the residential area,23 and the latter are already below
the CEQA threshold.
Attachments
23 Residents are assumed to be exposed 24 hours per day, 365 days per year, for 70 years. Worker exposure would occur
only during their time at their workplaces.
Attachments
7106/Summit Avenue Warehouse Project
Screening Health Risk Assessment April 2022
ATTACHMENTS
Attachments
7106/Summit Avenue Warehouse Project
Screening Health Risk Assessment April 2022
ATTACHMENT 1
ESTIMATION OF DAILY TRUCK TRIPS
TRAFFIC GENERATION ESTIMATESCAQMD Recommended Generation Rates 1.68 ADT/1000 sf (all vehicles)Fractions of All Vehicles0.64 ADT/1000 sf (trucks only) LHD2 (2‐axle) 0.0645Project warehouse area (1000 sf) = 92.38 MHD (3‐axle) 0.0865Total trips generated 155.1984HHD (4+axle)0.23Cars & lt trucks 0.619Trips GeneratedPCE Factor PCE Diesel Fraction # DieselLHD2 (2‐axle) 10.0103 1.5 15.01545 0.578 5.7859526MHD (3‐axle) 13.42466 2 26.84932 0.867 11.6391812HHD (4+axle)35.69563 3 107.0869 0.991 35.3743735Cars & lt trucks 96.06781 1 96.0678152.7995 53155.1984 245.0195Trucks/day59.13059
Attachments
7106/Summit Avenue Warehouse Project
Screening Health Risk Assessment April 2022
ATTACHMENT 2
SCREEN3 MODEL INPUTS AND RESULTS
12/07/21
20:05:08
*** SCREEN3 MODEL RUN ***
*** VERSION DATED 13043 ***
7102_Allard Warehouse (2021‐12‐07)a
SIMPLE TERRAIN INPUTS:
SOURCE TYPE = AREA
EMISSION RATE (G/(S‐M**2)) = 0.265200E‐08
SOURCE HEIGHT (M) = 4.5700
LENGTH OF LARGER SIDE (M) = 180.0000
LENGTH OF SMALLER SIDE (M) = 99.0000
RECEPTOR HEIGHT (M) = 0.0000
URBAN/RURAL OPTION = URBAN
THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED.
THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.
ANGLE RELATIVE TO LONG AXIS = 0.0000
BUOY. FLUX = 0.000 M**4/S**3; MOM. FLUX = 0.000 M**4/S**2.
*** FULL METEOROLOGY ***
**********************************
*** SCREEN AUTOMATED DISTANCES ***
**********************************
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC U10M USTK MIX HT PLUME MAX DIR
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) (DEG)
‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐ ‐‐‐‐‐ ‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐‐
90. 0.3357E‐01 5 1.0 1.0 10000.0 4.57 0.
100. 0.3516E‐01 5 1.0 1.0 10000.0 4.57 0.
200. 0.2629E‐01 5 1.0 1.0 10000.0 4.57 0.
300. 0.1700E‐01 5 1.0 1.0 10000.0 4.57 0.
400. 0.1173E‐01 5 1.0 1.0 10000.0 4.57 0.
500. 0.8556E‐02 5 1.0 1.0 10000.0 4.57 0.
MAXIMUM 1‐HR CONCENTRATION AT OR BEYOND 90. M:
120. 0.3719E‐01 5 1.0 1.0 10000.0 4.57 0.
*********************************
*** SCREEN DISCRETE DISTANCES ***
*********************************
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC U10M USTK MIX HT PLUME MAX DIR
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) (DEG)
‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐ ‐‐‐‐‐ ‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐‐
139. 0.3546E‐01 5 1.0 1.0 10000.0 4.57 0.
***************************************
*** SUMMARY OF SCREEN MODEL RESULTS ***
***************************************
CALCULATION MAX CONC DIST TO TERRAIN
PROCEDURE (UG/M**3) MAX (M) HT (M)
‐‐‐‐‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐
SIMPLE TERRAIN 0.3719E‐01 120. 0.
***************************************************
** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS **
***************************************************
04/14/22
16:06:55
*** SCREEN3 MODEL RUN ***
*** VERSION DATED 13043 ***
7106 ALLARD SUMMIT WAREHOUSE CONSTRUCTION
SIMPLE TERRAIN INPUTS:
SOURCE TYPE = VOLUME
EMISSION RATE (G/S) = 0.144700E‐01
SOURCE HEIGHT (M) = 7.5000
INIT. LATERAL DIMEN (M) = 31.2500
INIT. VERTICAL DIMEN (M) = 6.9800
RECEPTOR HEIGHT (M) = 0.0000
URBAN/RURAL OPTION = URBAN
THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED.
THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.
BUOY. FLUX = 0.000 M**4/S**3; MOM. FLUX = 0.000 M**4/S**2.
*** FULL METEOROLOGY ***
**********************************
*** SCREEN AUTOMATED DISTANCES ***
**********************************
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH
‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐ ‐‐‐‐‐ ‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐
100. 7.107 5 1.0 1.0 10000.0 7.50 40.92 13.61 NO
200. 4.355 5 1.0 1.0 10000.0 7.50 50.27 19.54 NO
MAXIMUM 1‐HR CONCENTRATION AT OR BEYOND 100. M:
100. 7.107 5 1.0 1.0 10000.0 7.50 40.92 13.61 NO
DWASH= MEANS NO CALC MADE (CONC = 0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER‐SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN‐SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
*********************************
*** SCREEN DISCRETE DISTANCES ***
*********************************
*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***
DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA
(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH
‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐ ‐‐‐‐‐ ‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐‐ ‐‐‐‐‐
140. 5.755 5 1.0 1.0 10000.0 7.50 44.70 16.05 NO
DWASH= MEANS NO CALC MADE (CONC = 0.0)
DWASH=NO MEANS NO BUILDING DOWNWASH USED
DWASH=HS MEANS HUBER‐SNYDER DOWNWASH USED
DWASH=SS MEANS SCHULMAN‐SCIRE DOWNWASH USED
DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB
***************************************
*** SUMMARY OF SCREEN MODEL RESULTS ***
***************************************
CALCULATION MAX CONC DIST TO TERRAIN
PROCEDURE (UG/M**3) MAX (M) HT (M)
‐‐‐‐‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐
SIMPLE TERRAIN 7.107 100. 0.
***************************************************
** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS **
***************************************************