# Flight: CO2 emissiefactoren 🇳🇱 ### :bulb: High-Level Description: CO2-emissiefactoren is a distinguished methodology originating from the Netherlands, designed to provide accurate emission factors across various sectors, including passenger aviation. With a focus on delivering clear and precise carbon metrics, the methodology is widely adopted by European stakeholders, offering them a reliable system for understanding and mitigating the carbon footprint of their activities. Within the aviation sector, CO2-emissiefactoren's approach stands out for its ability to consider multiple factors, such as aircraft type, engine specifications, distance traveled, and fuel efficiency. The methodology is continually updated to reflect the latest research and technological developments, ensuring that the carbon calculations remain both current and comprehensive. By offering detailed insights into the carbon impact of air travel, CO2-emissiefactoren equips airlines, policymakers, and travelers with the tools necessary to make more sustainable choices in the aviation industry. ### **Sample API Requests** #### A. Without audit mode (for pre-booking/quotes) ```json { "expand": ["items"], "items": [ { "audit": false, "type": "flight", "methodology": "CO2-EMISSIEFACTOREN-NL", "external_reference": "string", "origin": "MIL", "destination": "ORY", "booking_class": "first", "energy_scope": "wtw", "number_of_travelers": 1, "radiative_forcing_index": true } ] } ``` #### B. With audit mode (for finalized/post-booking calculations) ```json { "expand": ["items"], "audit_for": "", "items": [ { "audit": true, "type": "flight", "methodology": "CO2-EMISSIEFACTOREN-NL", "external_reference": "string", "origin": "MIL", "destination": "ORY", "booking_class": "first", "energy_scope": "wtw", "number_of_travelers": 1, "radiative_forcing_index": true } ] } ``` > **Note:** `audit_for` is optional. Provide when calculating on behalf of a specific Auditable entity; otherwise omit. **Defaults** * `"booking_class": "average"` * `"radiative_forcing_index": true` * `"energy_scope": "wtw"` ### **API request items** * `"type": "flight"` (required) * `"methodology": "CO2-EMISSIEFACTOREN-NL"` (required) * `"external_reference"`: A unique identifier that helps you link the resulting emissions to the requested item. Especially useful if multiple items are requested since SQUAKE cannot guarantee to keep the same order. The maximum length is 128 characters. * `"booking_class"`: If you don't pass a `booking_class`, then `fare_class` and `airline` are highly recommended. SQUAKE will then automatically resolve the correct `booking_class`. For `CO2-EMISSIEFACTOREN-NL`, this is optional with `average` as the default value. Values are `first`, `premium_economy`, `economy`, or `business`. * `"number_of_travelers"`: Minimum value is `1`. The default value is `1`. * `"origin"`: For airports use IATA/ICAO code (format: `^[A-Z]{3,4}$`, e.g. `"MUC"`), for other locations used in trade and transportation use UN/LOCODE codes (format: `^[A-Z]{2}\W?[A-Z2-9]{3}$`, e.g. `"DEHAM"`). You can also pass lat/long (format: `^[-+]?\d{1,3}\.\d{1,10}\s?,\s?[-+]?\d{1,3}\.\d{1,10}$`, e.g. `"+40.712,-74.006"`). * `"destination"`: For airports use IATA/ICAO code (format: `^[A-Z]{3,4}$`, e.g. `"MUC"`), for other locations used in trade and transportation use UN/LOCODE codes (format: `^[A-Z]{2}\W?[A-Z2-9]{3}$`, e.g. `"DEHAM"`). You can also pass lat/long (format: `^[-+]?\d{1,3}\.\d{1,10}\s?,\s?[-+]?\d{1,3}\.\d{1,10}$`, e.g. `"+40.712,-74.006"`). * `"distance_in_km"`: Prioritized over `origin` and `destination`. If you don't have a `distance_in_km`, you can use `origin` and `destination` and the distance will be automatically resolved. If you pass both `distance_in_km` and `origin`/`destination`, then `distance_in_km` will be used. * `"fare_class"`: The combination of `fare_class` and `airline` is mutually exclusive with `booking_class`. This is a single letter, e.g., `Y`, `J`, etc. * `"radiative_forcing_index"`: Controls if a multiplier that factors in gases emitted to the atmosphere when flying at altitude should be applied. The default value is `true`. * `"airline"`: The IATA Designator of an airline, e.g., LH. Airline names are also supported, SQUAKE will then automatically resolve it. * `"energy_scope"`: Values are `ttw` or `wtw`. The default value is `wtw`. * `"sustainable_fuels"`: Indicates the usage of sustainable fuels. This lowers the computed emissions in SQUAKE but is not part of the current official emissions frameworks. * `"carbon_reduction_percentage_of_total"`: The percentage of emissions reduction through the usage of sustainable fuel. The minimum value is `0`, and the maximum value is `1`. Default value is `0`. * `"audit"`: boolean (optional). Set to `true` to create immutable audit records for finalized calculations. Must be enabled for your account. ### **Sample API Response** ```json { "carbon_quantity": 633654, "carbon_unit": "gram", "items": [ { "carbon_quantity": 633654, "carbon_unit": "gram", "external_reference": "string", "type": "flight", "methodology": "CO2-EMISSIEFACTOREN-NL", "distance": 749.0, "distance_unit": "kilometer" } ] } ``` For more details about RFI: [Radiative Forcing Index](https://squake.notion.site/Radiative-Forcing-Index-1f8f0d7eb6e141a6ad7a3351bdc53f05?pvs=4) ### **Bibliography** * Lijst emissiefactoren (2025). CO2 emissionfactoren. Retrieved from * Milieu Centraal (n.a.). Retrieved from * Emissiefactoren van vliegverkeer in meer detail (Jan, 2022). MilieuCentraal. Retrieved from