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  • How do the different parts of particulate matter (PM) fit together?

    The various parts of PM in the NEI are related as follows. PM10-FIL > PM25-FIL because PM10-FIL includes PM25-FIL PM25-PRI = PM25-FIL + PM-CON This equation only applies at the process level. Because some sources only can report PM2.5 (due to test method differences), this equation does not apply to…

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  • How does PM2.5 relate to PM species such as EC, OC, SO4, NO3, PMFINE, and DIESEL-PM25?

    Primary PM2.5 estimates are speciated into the five PM species in the NEI: elemental (black) carbon (EC), organic carbon (OC), nitrate (NO3), sulfate (SO4), and the remainder of PM25-PRI (PMFINE). Diesel engine PM25-PRI and PM10 emissions are also labeled as DIESEL-PM25 and DIESEL-PM10 for mobile source diesel engines. For all…

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  • Does the distance to endpoint start at the process or stationary source boundary?

    When selecting the worst-case release scenario for Program 2 and 3 processes as required by 40 CFR §68.25, a stationary source owner or operator must analyze the release scenario that results in the greatest distance to an endpoint. Does the "greatest distance to an endpoint" refer to the greatest total…

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  • Using meteorological station data for off-site consequence analyses

    For the purpose of the offsite consequence analyses required under 40 CFR Part 68, Subpart B, there are several instances in which data gathered at a local meteorological station may be used to establish the modeling parameters of wind speed, atmospheric stability, temperature, and humidity for the stationary source. How…

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  • Underground storage tank off-site impacts to groundwater, drinking water, or soil

    For the worst-case and alternative release scenarios of an underground storage tank, should I consider any impact on groundwater, drinking water, or soil? No. As part of the worst-case and alternative release scenarios, you need to define the offsite impacts to the environment (40 CFR §68.33) by listing the environmental…

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  • Administrative controls considered when determining worst-case release quantity

    For the purpose of analyzing the worst-case release scenario required as part of the hazard assessment at 40 CFR Part 68, Subpart B, the worst-case release quantity is identified as the greatest amount held in a single vessel or pipe, taking into account administrative controls that limit the maximum quantity…

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  • Are Mechanical Controls Considered Administrative Controls?

    For the purpose of analyzing the worst-case release scenario required as part of the hazard assessment at 40 CFR Part 68, Subpart B, the worst-case release quantity is identified as the greatest amount held in a single vessel or pipe, taking into account administrative controls that limit the maximum quantity…

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  • Worst-case release from smaller process with larger distance to endpoint

    The owner or operator of a stationary source covered by the risk management program regulations must conduct a worst-case release scenario analysis as part of the required hazard assessment (40 CFR §68.25). The worst-case release is defined as the release of the largest quantity of a regulated substance from a…

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  • Can I use any previous three year meteorological data for worst case scenario?

    I am trying to complete my worst case release scenario for the Risk Management Plan under §68.25. I understand that I am required to use a wind speed of 1.5 m/s and F atmospheric stability class as specified in §68.22(b), unless I can prove that at no time over the…

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  • Can MOVES Report Output in Terms of Fuel Consumption?

    See More Frequent Questions about MOVES and Related Models . Although gallons of fuel consumed are not reported by MOVES, the factors used to convert total energy consumption (a MOVES reporting option) to gallons of fuel are contained in the FuelSubtype table (energy content, reported in kilojoules per gram of…

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  • How do I use MOVES at Project Scale?

    See More Frequent Questions about MOVES and Related Models . The MOVES model can estimate emissions at national, county or project scale. Project scale is useful for estimating an individual transportation project like an intersection or transit project, but it requires detailed inputs that describing the vehicle population and activity…

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  • How Can I Determine the Effect of Speed on Vehicle Emissions?

    See More Frequent Questions about MOVES and Related Models . MOVES can be run in either “Inventory” or “Emission Rates” mode. With Emission Rates, MOVES reports emission rates for the 16 average speed bins used by MOVES for each hour of the day and additional emission rate output that may…

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  • Criteria for selecting alternative release scenarios

    As part of the hazard assessment, owners and operators of Program 2 and Program 3 covered processes must identify and analyze alternative release scenarios (40 CFR §68.28). What criteria should be used when selecting an alternative release scenario? The owner or operator of a stationary source subject to the risk…

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  • How many worst-case release scenarios must be analyzed and documented in the RMP?

    As a part of the hazard assessment requirements in 40 CFR Part 68, Subpart B, I must analyze worst-case release scenarios and document certain analyses in my risk management plan (RMP). How many worst-case release scenarios must be analyzed, and how many analyses must be specifically documented in the RMP…

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  • Identifying public receptors and property with restricted access

    Does public receptor cover only buildings on a property or the entire property? If the owner of the land next to my site restricts access to the land, is it still a public receptor? Public receptors are not limited to buildings. For example, if there are houses near your property…

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