Instructions for Using Diesel Engine Screening Risk Assessment Tables
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Parameters Used for AB2588 Diesel Engine Screening Risk Tables
| Model | HARP2 |
| Engine Horsepower | 200,550,600,1500,2600 |
| Engine Operation Load | 50%, 100% |
| Emission Factor | 0.02 - 1.0 g/bhp-hr |
| Operation hours (annual) | 10,20,30,40,50,100,200,300,400,500,1000 |
| Source Type | Point |
| Dispersion Setting | Urban, Rural |
| Receptor Height | 1.2 meters |
| Stack Height | 3 meters |
| Stack Temperature | 622 Kelvin |
| Time Emissions Emitted | 12 p.m. - 4 p.m., All Day (most conservative betwen the two) |
| Meteorological Data | LAX (Urban Coastal), Banning (Urban Inland), Redding (Rural Inland) |
| Release Height | 3 meters |
| Polar Grid | |
| Number of direction radials | 36 |
| Starting radial degrees | 0 degrees |
| Direction increment | 10 degrees |
| Ring distances | 10 meters |
| Health Risk Assessment Parameters | |
| Analysis Type | Cancer risk |
| Receptor Type | Population wide |
| Exposure Duration | 70 years |
| Intake Rate Percentile | 95th percentile |
Use these steps when calculating a screening health risk assessment score for a facility with stationary diesel engines.
Step 1 | Before beginning your analysis, determine the Load, Engine Size, Emission Factor, Distance to Nearest Receptor, and Annual Hours of Operation for each of your engines. The district will help you determine the Urban/Rural Option. |
Step 2 | Click on the table with the engine size that is closest in size to your engine. |
Step 3 | Find the matrix that corresponds to your emission factor (either 0.01, 0.15, 0.40, 0.55, or 1.0 g/bhp-hr). If you do not know the emission rate of your engine, use 1.0 g/bhp-hr. |
Step 4 | Find the row that corresponds to the correct number of hours of operation (on the left of the table), and the column with the correct receptor distance to calculate the risk from that engine. |
Step 5 | Repeat these steps for the other engines and sum the results to get the total facility risk. |
Step 6 | Work with local air district to determine next steps. |
Example Calculation:
Step 1:
Engine size = 180 hp (maximum rated horsepower)
Emission factor = 0.40 g/bhp-hr (certified emission rate at maximum load - assume 1.0g/bhp-hr if unknown)
Annual hours of operation = 29 h (includes all operating hours, including maintenance and testing, except actual emergency hours)
Distance to nearest receptor = 53 m (measured from the engine to the nearest residential or commercial receptor)
Step 2: The 180 hp engine is closest in size to the 200 hp engine, so we will use the 200 hp table for this example.
Step 3: Click on the 200 hp table and find the matrix that is closest to 0.40 g/bhp-hr.
Step 4: Identify the row that corresponds to 30 hours (closest to 29 hours) and read across until you find the risk value that is directly under 50 meters (closest to 53 meters).
Step 5: Repeat as necessary and sum the results to get the total facility risk.
Step 6: Submit results of screening risk calculation to the local air district upon request.
Because some receptors may be located closer to the engine than the point of maximum impact (the PMI or area of highest risk), we have created tables that retain the higher risk numbers for distances closer than the PMI in order to ensure that these screening tables are still health conservative.