1. New Source Review: Modeling and Offsets
November 2, 2005
Judy B. Yorke
Yorke Engineering, LLC
x25

2. NSR Modeling Requirement
A demonstration that the new/modified source will not “cause a violation, or make significantly worse an existing violation…” of the NAAQS.
Exemptions are identified in Rule 1304, for example:
Replacements;
Emergency Equipment; and
Air Pollution Control

3. NSR Modeling Demonstration
SCAQMD Rule 1303 Appendix A
Screening Analysis
If hourly emissions are less than the values in Table A-1, the modeling requirement is satisfied
If source does not pass screening analysis, detailed modeling is required

4. Table A-1: Allowable Emissions
Heat Input Capacity (million BTUs/hr)
NOx (lbs/hr)
CO (lbs/hr)
PM10 (lbs/hr)
Noncombustion Source
0.068
3.7
0.41
< 2
0.20
11.0
1.2
>2
< 5
0.31
17.1
1.9
>5
< 10
0.47
25.9
2.8
>10
< 20
0.86
47.3
5.2
>20
< 30
1.26
69.3
7.6
>30
<40
1.31
72.1
7.9

5. Detailed Air Quality Modeling
Create dispersion model using SCREEN3 or ISCST3
Calculate highest pollutant concentration for receptors outside facility boundary
1-hour average
Annual average
Determine ambient pollutant concentration by taking highest value from most recent 3 years data
Add new concentration to ambient concentration
Modeling satisfied if sum does not exceed values in Table A-2.

6. TABLE A-2: Most Stringent AAQS
Air Contaminant
Averaging Time
Most Stringent Air Quality Standard
Nitrogen Dioxide
1-hour Annual
25 pphm* 5.3 pphm
500 ug/m3 100 ug/m3
Carbon Monoxide
1-hour 8-hour
20 ppm 9.0 ppm
23 mg/m3 10 mg/m3
Suspended Particulate Matter -<10um (PM10)
24-hour Annual Geometric Mean
50 ug/m3 30 ug/m3`
Sulfate
24-hour
25 ug/m3
* pphm = parts per hundred million

7. NSR-Offsets Goal of Offsets
Use emission reductions from existing sources to offset emission increases
Reductions more than compensate for increases and result in a net air quality benefit

8. Offset Ratio Generally, offsets are required at a 1.2-to-1 ratio
Some variations, e.g.,:
Priority Reserve
Offset Budget
RECLAIM NOx/SOx

9. Offset Exemptions Exemptions are identified in Rule 1304, for example:
Qualifying Replacements;
Emergency Equipment;
Air Pollution Controls;
Relocations;
Facilities with a PTE below thresholds

10. NSR-Offset Exemption Thresholds
Offsets are required if facility exceeds:

11. Cost of Offsets The cost of offsets vary with the demand…
Examples of market prices, current bids/offers*:
·         Non-RECLAIM Emission Reduction Credits -
o       PM10 ~ $65,000/lb
o       ROG ~ $1,500/lb
o       CO ~ $7,800/lb
·         RECLAIM Trading Credits -
o       NOx ~ $ /lb
o       SOx ~ $1.35-$3.5/lb
* From Christine Grandstaff of Cantor Fitzgerald ( )

12. Generating ERCs Rule 1309 defines requirements to obtain ERCs
Rule 1306 the emission decrease which may be considered
Requirements are very stringent

13. To Obtain ERCs
2 years of records demonstrating actual emissions must be provided
Actual emissions are discounted to current BACT emission rate
Discounted emissions are further cut by usage factor if operated less than 180 days/year.

14. Summary Review carefully BACT determination
Review offset and modeling applicability and requirements
Check permit conditions carefully
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