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URBEMIS 2002 Model Procedure
Screening Analysis Mode
Last Updated 8/2/04 10:00 AM

Introduction
"Screening Analysis Mode" uses default settings and only evaluates the unmitigated Area and Operational Phases of a project (omits the Construction Phase evaluation). This program design is intentional as there is no way to develop defaults for the vast possibilities of onsite equipment, operating schedules, and other variables associated with the construction phase of a project. In order to develop Construction Phase emission estimates one must utilize the refined analysis features of URBEMIS and ender project-specific details. A project that does not exceed any threshold of significance in the screening mode will not be required to perform an URBEMIS "refined analysis". A standard set of mitigation measures applicable to all projects are recommended for implementation.

Excerpt from URBEMIS User's Manual: By selecting screening analysis, the user will not be able to edit the default values for construction, area sources, or operational emissions. In addition, because the construction module depends on several key assumptions that must be reviewed by the user, the screening analysis mode only allows emissions to be estimated for the area and operational source categories.

Purpose
A screening analysis may be performed to generate a quick estimate (Initial Study) of project long-term and cumulative air emissions to determine if a refined analysis should be performed.  If the project exceeds the total pounds per day or cumulative tons per year Thresholds of Significance for NOx, ROG, or PM10, using the methodology described below, then a refined analysis should be performed. A project that does not exceed any of the thresholds in the screening analysis should be documented as a Mitigated Negative Declaration and "Standard Mitigation Measures for All Projects" should be implemented.

bullet Screening Analysis Mode Procedure:
In this example titled "test" we have chosen to perform a screening evaluation for a residential single-family housing project of 124 homes to determine if a refined analysis will be required.

Note: If any one of the thresholds are exceeded a refined analysis will be required for data submittal. If a refined analysis also exceeds a threshold after application of all feasible mitigation measures then an EIR recommendation is likely. If the application of mitigation measures reduces emissions below all thresholds then a Mitigated Negative Declaration recommendation is likely. A Negative Declaration should rarely be applied as there will be standard measures incorporated and monitored for all projects.

  1. Start URBEMIS
  2. Enter the desired Project Description
  3. Select Lower Sacramento Valley Air Basin
  4. Select Screening Analysis Mode and Open Screening Analysis
  5. Enter applicable Land Use Selection data; when finished select Apply Changes

Example Land Use Selection Entry Screen

  1. Select the Output button to generate an onscreen emissions estimate report
  2. Select the report printout categories as displayed below and print the report twice (one copy for your records and the other to be attached to the Project Description and Air Quality Screening Analysis Summary report and submitted to the air district during the CEQA review process.
  3. Save the file.
  4. Attach the "Air Quality Screening Analysis Summary" document and URBEMIS reports to the project cover page describing the project and submit for CEQA routing and review.


Example Report Generation Setup Page

 

bullet How to Evaluate, Prepare, and Submit the Screening Analysis Report Data
(Note: Example Screens and Reports are provided below)

Overview - Select the data from the printed reports or the onscreen display of the Summer Summary, Winter Summary, and Tons/Year Summary emission reports. Document the results in a MS Word document table or MS Excel spreadsheet or equivalent software and layout as provided below and compare these values against the thresholds to see if the project's emissions estimate exceeds the thresholds, therefore, requiring a refined analysis. Otherwise, a refined analysis is not required and the data submittal procedure described here meets air district report submittal requirements.

NOx and ROG - Using only the Summer Summary Report, document the NOx and ROG pounds per day unmitigated totals (Sum of Area and Operational Emission Estimates). Only summer lbs/day NOx and ROG are used to determine if the project will exceed the lbs/day thresholds.  Also, document NOx and ROG tons per year unmitigated totals from the Tons/Year Summary report (Sum of Area and Operational Emission Estimates).

[Note: NOx and ROG are precursors to Ozone; ozone is not directly emitted, it is formed later by photochemical reactions involving sunlight, heat, NOx and ROG. FRAQMD is designated nonattainment for the State Ozone standard. Ozone concentrations become elevated during the warmer months of the year because the chemical reaction to form ozone from NOx and ROG emissions requires heat and ultraviolet radiation from the sun. [The 180-day ozone season is defined as starting on May 1st and ending on October 31st].

PM10 - FRAQMD is also nonattainment for the State PM10 standard. Using the Summer Summary and Winter Summary reports, compare summer and winter PM10 pounds per day unmitigated totals (Sum of Area and Operational Emission Estimates); document the higher PM10 value from the two reports to compare with the threshold.  Typically, winter PM10 concentrations are higher than summer due to wood burning residential heating.  Also, document PM10 tons per year unmitigated totals from the Tons/Year Summary report (Sum of Area and Operational Emission Estimates).

For this example our reporting document may look similar to the following:
 

 

Air Quality Screening Analysis Summary
URBEMIS Screening Analysis Mode

Date: August 10, 2004


URBEMIS Project Title: Test
CEQA Project Title: The 124 Single-Family Home Housing Project
Project Location: 938 14th Street, Marysville
Proposed Project Start and End Dates:  May 1, 2005 / October 31, 2005

Name/Title of Person Performing Analysis: Larry Matlock, Senior Air Quality Planner
Company/Mailing Address: Feather River AQMD, 938 14th Street Marysville, CA 95901
Contact Phone/Email:  530-634-7659x202 / lmatlock@fraqmd.org

Evaluation of Project Unmitigated Emissions

Long-Term Emissions NOx ROG PM10
Summer, lbs/day 19.75 16.37 -
Winter, lbs/day     74.59
Thresholds, lbs/day 25 25 80
Exceeds Threshold (Yes/No) NO NO NO
Cumulative Emissions NOx ROG PM10
Tons/Year 10.68 3.73 4.64
Thresholds, tons per year* 25 25 25
Exceeds Threshold (Yes/No) NO NO NO

* Interim "Cumulative Thresholds of Significance" (based on New Source Review Offset Thresholds
  used to permit stationary sources). Not yet approved by the FRAQMD Board of Directors.

Project Evaluation Summary
 Neither the long-term nor cumulative thresholds have been exceeded for the Area and Operational Phase of the "Test" project, therefore, a refined URBEMIS analysis is not required and the Standard Mitigation Measures for All Projects and any air district recommended measures will be implemented and incorporated into the Mitigation Monitoring Plan and submitted for adoption with this project as an air quality Mitigated Negative Declaration. Furthermore, quantification of emission reductions attributed to adopted mitigation measures will not be required.

Any mitigation measures that are not deemed feasible, or any proponent-proposed alternative measures, will be documented with a written explanation and submitted for public review and FRAQMD/Lead Agency review and approval prior to scheduling the project for final review and approval before the governing Board at a public hearing.  

 

 

Example Summer Summary Report

 

Example Winter Summary Report

 

Example Tons/Year Summary Report