Nowadays both air quality and climate change are two themes that are of interest and cause concern to municipalities. Even they are closely related, it´s a case of different problems that requires analysis tools and specific action strategies.In order to design policies tailored to the actual situation in each city, there are no generic measures or decisions to be taken; rather, it is essential to have objective numerical values in order to act efficiently and justifiably.essential to count with nu
In both cases are involved issued gases by the human activity, although not all has the same effect. In one side, atmospheric pollutants affect directly to air quality (nitrogen oxides, carbon monoxide, sulphur dioxide, ammonia or even particulate matter, which, although not gases, have a significant impact on health). On the other side, greenhouse gases, such as carbon dioxide, methane, nitrous oxide or fluorinated gases, which main effect is contribute to global warming.
But les us now focus on the gases that need to be taken into account in local authority policies to combat climate change and move towards climate neutrality, without forgiven that other pollutants are crucial to air quality and health protection policies.
How to measure the emissions of a municipality: the base to design efficient climate policies
If we look at it at the molecular level and we analyse the properties of these gases, we see that some atmospheric pollutants has direct effects over human health, while some certain greenhouse effect gases has an elevated capacity to mantain heat at the atmosphere and contribute to global warming. But if we focus on urban inventories linked to energy consume, emissions volume and by presence on the main emissions sources, the reference gas it is usually the carbon dioxide. In fact, when all greenhouse effect gases are considerer together, their emissions are usually expressed such as equivalent CO2 (Co2eq), a unit that takes into account the different Global Warming Potential (GWP) of each gas and allows them to be compared against a single benchmark.
The prevalence of carbon dioxide in the energy sectors means that it is the predominant gas in most urban emissions inventories. However, in sectors such as waste management, wastewater treatment and certain agricultural and livestock activities, methane and nitrous oxide can account for a significant proportion of emissions.
What is a Reference Emissions Inventory (IER)?
To know where these emissions originate and reduce them in an efficient way, municipalities elaborate a Reference Emissions Inventory (IER). These tools allow quantify emissions associated with different activities developed on the city and constitute the starting point to design climate policies based on data.
In the methodology we use at CARTIF, the inventory organiza the information in three main areas: city council area, PACES analysis area and municipal area. First one evaluate emissions of different areas of the own city council, such as, transport, own fleet, own energy production, etc. Second one is maned in that way because the clasification is inherited from Plans of Action for the Climate and Energy Sustainable (PACES), an estrategy boost on the framework of Convenant of Mayors that help municipalities to reduce emissions, improve energy efficiency and adapt to climate change. And finally municipal area, which consists of everything not included in the previous one, such as industry or agricultural and livestock (primary), even we have to take into account isn´t a rigid clasification.
What is a Reference Emissions Inventory (IER)?
A municipal emissions inventory is a tool that quantifies the greenhouse gas emissions generated by a city’s activities. It enables the identification of the main sources of emissions and the design of data-driven climate policies to move towards climate neutrality.
How is a municipal emissions inventory calculated?
Inside the sector of each area, the calculations of these emissions should face two major obstacles: on the one hand, the availability of the needed data, where for example city council data is directyl accesible while data such as fossil fuel consume in industry or in residencial buildings requires estimation and stadistical disaggregation processes, as they are not usually available at the required level of municipal detail. On the other hand, for some areas such as transport, it is necessary to work with information such as street network or a selection of communication nodes to generate data in an indirect way that allows realizing a coheretn statistical evaluation. All of this highlights the importance of counting with specialised equipments able to combine data from different sources, apply international recognised methodologies and obtain consistent inventories and comparable in time.
In most urban sectors, particularly those related to energy consumption, emissions are estimated on the basis of the energy consumed (or produced). However, there are sectors such as waste management, certain industrial processes or some agricultural activities where emissions are calculated using other specific parameters. Each energy source or activity has a specific emission factor that relates the unit of consumption or activity (kWh of electricity, litres of fuel, Nm³ of natural gas, tonnes of waste, etc.) to the emissions generated, expressed in tonnes of the corresponding gas or, when different greenhouse gases are aggregated, in tonnes of CO₂ equivalent (tCO₂eq).
Within each sector, consumption and emissions figures are normally broken down by energy source used and, where appropriate, by further sub-categories, such as vehicle types in the transport sector or municipal areas in the utilities sector. Furthermore, it is useful to present aggregated figures by sector and by year, as this allows the trends in consumption and emissions over time to be visualised from the reference year (known as the ‘baseline’) to the most recent year for which data is available.
From data to action: how an inventory helps reduce emissions
At CARTIF, we have carried out various emissions studies for towns and cities, both as part of the Covenant of Mayors initiative — as in the case of Logroño — and through specific studies for local councils, such as Ponferrada. This work provides an objective snapshot of each municipality’s starting point and forms the basis for developing Action Plans, assessing climate risks, prioritising investments and measuring the actual impact of public policies on climate change mitigation and adaptation.
👉 Does your local authority need to draw up or update its emissions inventory? At CARTIF, we help local authorities quantify their emissions, define decarbonisation strategies and design climate plans based on scientific evidence. Get in touch with our team to find out how we can help you.
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