HIGHLIGHTS
- The new law on climate change and energy transition that has entered into force will force hundreds of municipalities in Spain to mark out low-emission zones.
- Environmental monitoring systems with air quality sensors such as Kunak AIR Pro are useful tools for analysing how these areas develop.
- Implementation experiences in numerous European cities have been positive, with a reduction in both the number of vehicles that pass through urban centres every day and on main pollutant levels.
What are the LEZs?
Low Emission Zones (LEZs) are geographical areas in cities or regions where vehicle access is restricted or regulated on the basis of their pollutant emissions. The aim of these zones is to reduce air pollution and improve urban air quality by promoting the use of cleaner and more sustainable modes of transport.
To find the origin of this initiative, we have to travel back to Stockholm in 1996. The Swedish capital was the first city to implement such zones. However, this solution has spread to other European cities, with London being one of the leading exponents of its application.
In Spain, these zones have been created in response to the Climate Change Law and are designed to reduce polluting emissions from vehicles, as well as to create safer and more liveable urban environments.
Thus, all cities with more than 50,000 inhabitants must establish LEZs, and also municipalities with more than 20,000 inhabitants that do not meet air quality criteria.
LEZs often use environmental labelling to restrict access for the most polluting vehicles and thus contribute to improving the air and quality of life in cities.
What are the objectives of Low Emission Zones?
Improve air quality
The main objective of LEZs is to reduce harmful substances in the air, such as nitrogen oxides and fine particulate matterAtmospheric particulate matter are microscopic elements suspended in the air, consisting of solid and liquid substances. They have a wide range of sizes an...
Read more, which are harmful to human health and the environment.
Promoting sustainable mobility and mitigating climate change
These zones aim to promote the use of non-polluting vehicles, such as electric bicycles, electric vehicles and public transport, to reduce dependence on cars with internal combustion engines.
By reducing the use of motorised vehicles, the aim is to reduce greenhouse gas emissions in the LEZ, for which measurable and quantifiable objectives are defined and compliance will be monitored through established indicators.
In addition to these mobility initiatives, less GHG-emitting technologies and other pollutants will be promoted, as well as intelligent air-conditioning systems in the building sector. The LEZ also promotes adaptive urban interventions to mitigate the heat island effect and improve the sustainability and ecological resilience of cities.
Reducing noise pollution
LEZs must meet established noise quality targets by improving noise levels. In addition, they can use specific tools and create quiet zones to ensure a noiseless environment, contributing to a more peaceful and less stressful urban environment for its inhabitants.
Enhancing environmental awareness
LEZs also serve as a constant reminder of the importance of environmental protection and the active role citizens should make in preserving their environment.
Why are low-emission zones necessary?
Emissions caused by road traffic are today one of the main sources of pollution in urban areas. They seriously compromise air quality. And it should not be forgotten that this factor is behind thousands of premature deaths and health problems.
It is therefore imperative to monitor the evolution of pollutants associated with road traffic, at least nitrogen dioxideNitrogen dioxide (NO2) is a harmful gas whose presence in the atmosphere is mainly due to the use of fossil fuels in combustion vehicles and industrial act...
Read more (NO2) and PM10 and PM2.5 particles, and to control the established limits.
But motor vehicles also contribute to global warming through CO2 emissions. In fact, according to data from the International Energy Agency and the International Council on Clean Transportation, road traffic accounts for almost 75% of total transport emissions.
Carbon dioxideCarbon dioxide (CO2) is a gas that occurs naturally in the atmosphere and plays a crucial role in the life processes of the planet. This gas, also known as...
Read more (CO2) is one of the main greenhouse gases. The increase in its concentration, mainly due to the burning of fossil fuels, largely explains the increase in the temperature of the earth’s surface. Limiting this increase in temperature is one of the maximum commitments acquired in the Paris Agreement, ratified by Spain in January 2017 and, therefore, legally binding.
Air quality sensors as an indicative measurement in a LEZ:
Air quality sensors used in LEZs must meet certain data quality standards. This means that they must provide data with low margins of error for both gases and particulate matter.
The sensors must have certifications or meet certain specifications to ensure their accuracy and reliability. For example:
- Technical Specification CEN/TS 17660-1:2022: It classifies air quality sensors into three classes (1, 2 and 3) according to their accuracy and reliability. The purpose is to ensure that the data obtained is consistent and meets established quality standards. Within this classification, Class 1 sensors, also known as indicative measurement, are noted for their high accuracy and are considered the most suitable for use in the LEZ due to the high quality of the data they provide.
- MCERTS certification: It is a quality standard that ensures that certified monitors will provide PM10 and PM 2.5 particulate matter data with an uncertainty of less than 50%, the required margin of error for indicative measurements, to assure that the technology used for particulate matter monitoring is aligned with the data quality objectives.
Importance of compliance
Compliance with these regulations is crucial to ensure the reliability of data. Reliable data are essential for:
- Making informed environmental policy decisions.
- Transparently informing the public about air quality.
- Evaluate the effectiveness of measures implemented in the LEZs.
Real measurements vs. Estimations
Measurements must be real and direct measurements of pollutants, not estimates or secondary data. This is essential to:
- Accurately reflect air quality in real-time.
- Detect pollution peaks and take immediate action.
- Maintain data integrity and public confidence.
- Una ley que promete y compromete
One of the main objectives of this new regulatory framework is to advance the decarbonisation of the economy. After all, reducing atmospheric emissionsAtmospheric emissions are pollutants emitted into the air, mainly as a result of human activities such as industry, transport by combustion vehicles and en...
Read more is a sine qua non condition for maintaining hope around the commitments of the 2015 Paris Agreement and action programmes such as Towards Zero Pollution for Air, Water and Soil.
How to reduce atmospheric emissions?
Committing to activities that contribute towards minimising emissions is undoubtedly one of the best ways. Thus, this law outlines a series of strategies aimed at:
- Promoting renewable energies.
- Refurbishing buildings to improve energy efficiency.
- Reducing emissions in key sectors such as seaports, is one of the areas in which Kunak has become a benchmark company, thanks to its air quality monitoringControlling air quality is an essential task in order to enjoy optimal environmental conditions for healthy human development and to keep the environment i...
Read more systems. - Making a decisive commitment to sustainable mobility.
However, instruments like low-emission zones certainly stand out, mainly because of the change they will bring to the urban fabric.
Low emission zones, fewer polluting vehicles, higher air quality
From 2023, many cities in Spain will have to display a sign like the one below.
Recently approved by the Directorate-General for Traffic, this new indication will inform drivers that they are entering a low-emission zone.
Global CO2 emissions from transport
Source: Our World in Data, October 2020
Air quality monitoring systems in an LEZ
In Low Emission Zones (LEZs), air quality monitoring is essential to protect public health and the environment. To ensure effective monitoring, different methods are used:
Reference instruments
These are reference methods in environmental monitoring and have traditionally been used to measure air quality in a city. Equipped with precision technology, these stations provide accurate and reliable data on pollutants such as PM2.5, PM10, ozone, nitrogen dioxide and sulphur dioxideSulphur dioxide (SO2) is a colourless gas with a pungent odour that causes an irritating sensation similar to shortness of breath. Its origin is anthropoge...
Read more.
Sensor-based air quality stations
These are new-generation devices that provide real-time indicative measurements. Although they do not replace reference stations, they complement their measurements by cost-effectively providing greater spatial coverage. They can measure multiple pollutants and meteorological parameters simultaneously. Their compact design and autonomous operation allow easy installation in multiple sites, while their simple maintenance reduces operational costs. In addition, their ability to incorporate additional probes for the measurement of other environmental variables makes these stations a comprehensive and flexible solution for air quality management.
Personal exposure monitoring sensors
These portable sensors are used to monitor the exposure of persons to specific pollutants. Although their reliability may be lower compared to fixed stations, they are useful for epidemiological studies and for raising awareness of personal air quality.
Comparative table of various methods of measuring air quality:
Reference instruments and equivalents (AQMS)
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Sensor-based air quality stations
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Low-cost air quality sensors
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How are the LEZs in Spain?
Low Emission Zones (LEZs) are urban areas where the circulation of more polluting vehicles is restricted to improve air quality. In Spain, Law 7/2021, on climate change and energy transition, obliges municipalities with more than 50,000 inhabitants and island territories to establish LEZs by 2023. Royal Decree 1052/2022 specifies the minimum requirements for the implementation of LEZs, such as project objectives, content, extension, delimitation and access conditions.
These initiatives aim not only to improve air quality but also to encourage a shift towards more sustainable and healthier mobility for citizens.
Before designing LEZs, it is recommended to carry out a preliminary study to determine the initial situation and to identify the hot spots in the city. This makes it easier to delimit the area of influence subject to restriction. The best way to undertake this analysis is to use proper tools to help define the hotspots and to quantify the levels of air pollution before and after the implementation of the actions. This pre-examination should also take into consideration how to limit the delivery of traffic to other areas and thus transfer the associated pollution problems.
Low Emission Zone in Madrid
In Madrid, the LEZ is called ‘Madrid Low Emission Zone‘ and bans the access and circulation of vehicles with environmental classification A in the Vehicle Register of the General Directorate of Traffic.
Madrid’s LEZ is an integral initiative within the Sustainable Mobility Ordinance that seeks to protect the health of citizens and visitors by complying with the nitrogen dioxide limits established by air quality regulations. It applies to all public roads in the municipality of Madrid and has been implemented in phases, starting in 2022 with restrictions within the M-30 and expanding to the whole municipality from January 2024. Access to the most polluting vehicles is restricted and transitional regimes are in place to facilitate the adaptation of citizens.
Low Emission Zone in Barcelona
The Barcelona LEZ, known as the ‘Rondas de Barcelona LEZ‘, is one of the largest in southern Europe, covering more than 95 km². It includes the municipal area of Barcelona (except for some specific areas) and parts of neighbouring municipalities. It was established to reduce the circulation of polluting vehicles and is applied progressively according to the DGT environmental label. Since January 2020, restrictions have been incorporated for different categories of vehicles, to improve air quality and guarantee the right to health.
Low Emission Zone in Bilbao
The Bilbao LEZ was launched in 2024 and covers an area of approximately 2 km² in the Abando district, including key areas such as the Guggenheim Museum and the Doña Casilda de Iturrizar Park. Traffic restrictions for the most polluting vehicles are applied on working days, Monday to Friday, between 7:00 and 20:00 hours. Number plate readers carry out access control, and vehicles without a sticker or with a B sticker have restricted access and parking, with some exceptions and moratoriums.
The Bilbao Low Emission Zone represents an important step forward in environmental monitoring, establishing a state-of-the-art hybrid network for measuring air quality. This new network complements the existing official network, extending coverage and providing more accurate and detailed data on urban atmospheric conditions. Its implementation allows citizens, researchers and policymakers to get a wider and more accurate picture of the air they breathe.
The integration of advanced technologies and highly sensitive sensors such as Kunak AIR Pro air quality stations into this hybrid network facilitates the detection of a wide range of pollutants in real-time. This is key to making informed decisions on public health policies and sustainability strategies. In addition, the network fosters transparency and public awareness, as the data collected is accessible to all, thus promoting greater community participation in improving Bilbao’s environmental quality.
Environmental impact assessment of a LEZ
In almost every area of our lives, it is essential to measure to improve. This is what Kunak instruments offer, a system to accurately and reliably assess the environmental impact of a LEZ. The Kunak AIR solution makes it possible to map the levels of pollutants before and after the implementation of a low emission zone and thanks to the data provided by the sensor network it is possible to analyse them to assess whether their effects are positive, negative or zero. Because, in short, the main objective of any LEZ is to protect the health of citizens.
The data provided by the sensor network helps to make informed decisions, identifying critical points of pollution, the main sources that raise the levels of specific pollutants, etc., which are very useful for the development of sustainable mobility strategies.
Kunak’s proposal
Administrations, regarding LEZs, need tools or resources that allow them to manage issues such as the levels of various pollutants in the urban environment in an agile, quick and simple way. For this reason, it is essential to have solutions such as those offered by Kunak, a comprehensive solution that includes both the sensors to measure pollution and the software that makes it possible to analyse the data provided by the sensors to make informed decisions that, ultimately, help to protect the health of citizens.
It is also important that such data can be integrated with other platforms in the low-emission zone ecosystem, thereby increasing the two-way interoperability of data for integrated air quality management.
A prime example is hybrid air quality networks. These networks combine the advantages of two complementary technologies to provide a unified view of environmental data. In a recent webinar, we explored this approach and also discuss it in this article. Platforms such as Kunak Cloud enable the integration, management and analysis of environmental data, helping to better understand and make informed air quality management decisions.
Like data from official air quality monitoring networks, data from Kunak stations can be shared through public platforms in a simple, clear and homogeneous way through an indicator such as the air quality index (AQI), promoting information transparency, and easing citizens’ understanding of air quality.
Benefits of Kunak’s solution for LEZs
- Diagnose the air quality of the LEZ.
- Monitor in real-time, and obtain reliable data on pollutants, noise levels and meteorological conditions.
- Analyse hotspots requiring immediate attention.
- Evaluate the impact and effectiveness of policies and actions implemented to improve air quality.
- Design strategies and action plans with reliable data to ensure that targets are met.
- Provide information transparency by giving access to environmental information (ICA).
Learning from other cities
Londres: from low emission to ultra-low emission zones
The example of the British capital is possibly one of the most significant in Europe.
The implementation of these areas, undertaken in several phases, started in 2008 with the aim of addressing and reducing the enormous impact caused by the daily traffic inundating its streets, which placed the city among the most polluted European cities. Compared to previous programmes, the degree of compliance by users was over 95% from the early stages (2).
London currently establishes two types of areas with specific air quality standards:
- Low Emission Zones (LEZ) are in force 24 hours a day, 7 days a week (with the exception of 25 December). Vehicles driving through them while failing to meet emissions standards will be hit with a daily charge of between £100 and £300.
- Ultra Low Emission Zones (ULEZ) are in effect 24 hours a day, 7 days a week (except 25 December), and vehicles that do not meet the standards will be hit with a charge of £12.50 per day for cars, motorcycles or vans and £100 for heavy goods vehicles.
By implementing these measures, especially after launching the ULEZs (2019), has made it possible to cut NO2 pollution levels by more than 35%. Due to their success, ULEZs will be extended from October 2021.
París: results of the Crit’Air system
Paris’ low emission zones came into force in 2015, initially limiting access to heavy goods vehicles registered in or after October 2001.
However, in 2016, France introduced the Crit’Air national air quality certificate, which applies to all vehicles. It defines 5 categories according to the vehicle, fuel and emission type, identifying each means of transport with a sticker which must be visible. This system currently regulates access to different areas of Paris. Various calendar goals have been set during its operation, which will end in 2030. From that year onwards, only electric and hydrogen-powered vehicles can drive in the city and metropolitan areas.
As a result of these measures, París‘ traffic has reduced by 31%. In terms of NOx levels, with the implementation of the most restrictive scenarios, it is estimated that in 2024 pollutant emissions could be between 76% and 87% lower than 2016 levels.
Frequently asked questions (FAQs) on LEZs
What is the role of an environmental monitoring system?
An environmental monitoring system in Low Emission Zones (LEZs) is essential to evaluate the effectiveness of implemented policies. These systems collect real-time data on air quality and noise, allowing authorities to adjust vehicle restrictions and other regulations to achieve environmental sustainability goals. In addition, continuous monitoring facilitates the identification of areas where pollutant limit values are exceeded, allowing targeted interventions to protect public health.
When do LEZ fines start?
Fines in a LEZ begin once the access and movement restrictions are fully operational and the corresponding signage is clearly established. Penalties for entering an LEZ without the appropriate sign or in breach of regulations may vary according to local regulations. It is important to be aware of the effective start dates of LEZs in each locality, as they vary according to local legislation and implementation.
Which vehicles can enter the Low Emission Zone?
In LEZs, ECO and Zero Emission vehicles can generally circulate without restrictions. B and C labelled vehicles may have access, but are usually restricted to parking in private car parks. Specific regulations may vary between cities, so it is advisable to consult local regulations for precise details on applicable restrictions and exemptions.
How to see the LEZ on Google Maps?
To view Low Emission Zones (LEZs) on Google Maps, you can use the app’s alert function, which notifies you when you are approaching a LEZ. Although this feature is available on a limited basis, it is expected to be expanded to more cities. For active LEZs, such as in Barcelona, select a vehicle journey that includes the LEZ area and you will receive a notification. In addition, you can search for specific user-created maps outlining LEZs in cities such as Madrid.
Conclusion
Low-emission zones are useful tools to reduce pollution levels in cities. When designed correctly, they work and in those cities that have been using them for some time, results are positive.
However, their implementation requires support elements such as air quality monitors. Checking the evolution of the LEZs requires rigorous, high-quality data to be made available, as those offered by Kunak solutions.
Sources consulted
- (1) Salas, R., Perez-Villadoniga, M., Prieto-Rodriguez, J., & Russo, A. (2021). Were traffic restrictions in Madrid effective at reducing NO2 levels?. Transportation Research Part D: Transport And Environment, 91, 102689. https://doi.org/10.1016/j.trd.2020.102689
- (2) Holman, C., Harrison, R., & Querol, X. (2015). Review of the efficacy of low emission zones to improve urban air quality in European cities. Atmospheric Environment, 111, 161-169. https://doi.org/10.1016/j.atmosenv.2015.04.009
