Compact sensors help to improve air quality in European Green Capital 2021

Air quality being measured in Lahti
Sep 6, 2021

Vaisala, the Finnish measurement technology company, is working with the city of Lahti to find cost-efficient solutions for small and midsized cities to improve the quality of life with reliable real-time air quality insights.

Lahti, a mid-sized Finnish city, has been awarded the hugely prestigious title of European Green Capital 2021. Previous winners include Nantes, Copenhagen, Bristol, Ljubljana, Essen, Nijmegen, Oslo, and most recently Lisbon.

Green Capital award

In Finnish, the word ‘lahti’ means ‘bay’ so it is appropriate that Lahti should be the first city in Finland to win this award in recognition of environmental initiatives that began with the conservation of Lake Vesijärvi in the 1980s. Situated on the southern tip of the lake, about 100 kilometers north east of Helsinki, Lahti is home to 120,000 people, including the Formula One driver Valtteri Bottas.

With more than two thirds of Europeans living in towns and cities, urban areas present many of the environmental challenges facing society. The European Commission therefore established the annual European Green Capital Award in 2008 to promote and reward commitment and innovation to resolve these issues.

Lahti’s award recognises the city’s longstanding environmental achievements, but it has ambitious plans for the future, such as carbon-neutrality by 2025, and large scale cooperation projects have been launched during 2021. One such project is a partnership with Vaisala, which is currently celebrating being ranked 14th in the Financial Times list of 300 European climate leaders.

Lahti and Vaisala – partners in sustainability leadership

Vaisala is a global leader in weather, environmental, and industrial measurements. “Our partnership with Lahti is a logical step,” explains Marjo Hietapuro, Vaisala’s Sustainability Manager. “Sustainability really is at our core, and it is visible not only in our own operations but throughout our value chain. However, Vaisala’s greatest impact on sustainability stems from the application of our solutions.” 

Vaisala’s meteorological solutions are employed by customers around the world; helping to monitor weather and to better adapt to climate change, for example. These solutions focus on people’s safety, sustainability, the protection of property, and efficient processes; utilizing reliable measurements for decision support in all weather conditions. In addition, the company’s industrial measurements division develops technologies that enable organisations to optimize processes, operate more efficiently, improve product quality and reliability, and demonstrate regulatory compliance. At the same time, Vaisala’s solutions help reduce waste and energy consumption, lower greenhouse gas emissions and reduce carbon footprint.

A good example of a Vaisala product that is helping to fight climate change is an award-winning unique, EX-certified, in-line multi-gas instrument, measuring methane, carbon dioxide and humidity at biogas plants. This technology helps users to optimize the generation of renewable energy, derive more value from organic waste; improve profitability; lower greenhouse gas emissions, and recycle agricultural nutrients.

Vaisala also provides in-line measurement technology for liquid products; helping customers in industries such as food & beverage, brewing, dairy, semiconductors and pharmaceuticals to reduce waste and save energy, whilst improving quality and saving costs. Vaisala’s measurement sensors and systems deliver the same benefits in a wide variety of industries, such as pharmaceutical, power generation and transmission, HVAC, semiconductors, automotive, and the food industry.

Initially, the partnership between Vaisala and Lahti is focusing on air quality, and involves the installation of compact air quality monitoring sensors in the city centre.

Air quality

Air pollution causes an estimated 7 million premature deaths per year globally, 400,000 of which are in Europe. While Finland enjoys better air quality than most countries, some 1,800 premature deaths still occur every year. According to the World Health Organization, by tackling air pollution levels, countries can reduce the human and financial burden of disease from stroke, heart disease, lung cancer, and both chronic and acute respiratory diseases, including asthma.

In its ‘Air quality in Europe - 2020 report’ the European Environment Agency estimated that in 2018 long-term exposure to particulate matter with a diameter of 2.5 µm or less (PM2.5) in Europe (including 41 countries) was responsible for approximately 417,000 premature deaths. Furthermore, 55,000 premature deaths resulted from NO2 exposure and 20,600 premature deaths were caused by exposure to ground-level ozone.

For decades, the EU has sought to improve air quality by controlling emissions of harmful substances into the atmosphere, improving fuel quality, and integrating environmental protection requirements into the transport, industrial and energy sectors. The EU's clean air policy is based on three main pillars:

(1)    the Ambient Air Quality Directives (EU, 2004, 2008), which set out air quality standards and require Member States to assess air quality and to implement air quality plans to improve or maintain the quality of air; 
(2)    the NEC Directive (EU, 2016), which establishes national emission reduction commitments; and 
(3)    source-specific legislation establishing specific emission and energy efficiency standards for key sources of air pollution.

All countries regularly exceed the EU air quality standards; particularly in urban areas where buildings act as canyons; retaining vehicle emissions (especially from old diesel engines) and causing the concentrations of key pollutants such as particulates and NO2 to rise significantly. Monitoring therefore performs a vital role – enabling the identification of pollution hotspots, helping with source attribution and providing a means with which to evaluate the success of mitigation measures.

Air quality in Lahti

Prior to the partnership with Vaisala, air quality was not monitored at the heart of Lahti’s city centre; mostly due to challenges locating the reference stations at key sites. However, the company’s Hannamari Jaakkola says: “Combining good cooperation with Lahti Environmental Services and our experience in other countries, we were able to identify the locations at greatest risk of pollution. We therefore installed our latest compact air quality sensors at a busy intersection in the city centre’s market area.

“Pollution from vehicles is likely to be a significant concern, but Finland’s cities and highways are less congested than in many other European countries, so we are hoping that particulate and NO2 levels will be low. However, wood burning is common in the Nordic countries so we may find elevated pollution levels in Lahti from heating stoves.

Developments in air quality monitoring

The lack of air quality monitoring in pollution hotspots is replicated in many thousands of towns and cities around the world. This is because traditional air quality monitoring stations (AQMS) employ expensive reference-grade analysers that are often located inside large air-conditioned containers that may require planning permission to install. These systems also require regular service and calibration that significantly adds to operational costs. As a result their numbers are low, and they are rarely located at pollution hotspots. Nevertheless, by employing reference method analysers, these stations are able to provide high levels of accuracy and precision in the data that they deliver.

In the past, the only low-cost alternatives to reference stations were passive diffusion tubes, which can be quickly and easily deployed on a street lamp post for example. However, this method only provides a retrospective assessment of a single parameter, often NO2; providing an average concentration for a period of a few weeks. Consequently, this method does not provide temporal pollution insights and does not provide a comparison with EU or WHO hourly-average air quality standards.

In recent years, research has shown that pollution levels in urban areas can greatly exceed the measurements provided by the nearest reference AQMS, so there has been a growing demand for more flexible, lower cost monitors that are able to supplement data from reference stations.

The Vaisala compact air quality sensor

Responding to the demand for compact sensors that are able to fill the gaps between reference AQMSs, Vaisala has developed a compact air quality monitoring sensor that can be installed quickly and easily, delivering wireless air quality data 24/7. These sensors are delivered factory calibrated, but their performance can be enhanced by co-locating them with reference stations prior to deployment. “Of course, our compact air quality sensor should not replace a reference station,” explains Hannamari Jaakkola, “but it will greatly complement the data from the reference stations and provide a flexible tool that can easily be moved to the locations of greatest concern; providing essential information for urban managers and planners.”

As a continuous sensor, Vaisala’s air quality monitoring solution is also able to provide real-time data, but the greatest benefit of continuous data is the ability to identify temporal variation such as pollution peaks during rush hours. 

Lightweight and running on low power, Vaisala’s solution can be installed in almost any location, and with wireless internet connectivity it is easy for users to view data, either directly from the sensor, via Vaisala’s or a customer´s own gateway, or with an API from Vaisala´s cloud platform.

Smart air quality monitoring networks

Vaisala is well-known as the world’s leading provider of meteorological solutions, and is highly experienced in the development of large monitoring networks. “This is a major benefit for our air quality customers, because that means we have the tools and expertise to help them exploit the benefits of a smart air quality monitoring network, whilst also considering the influence of weather,” says Hannamari Jaakkola.

“The value of a network is greater than the sum of its component parts,” she explains. “This is because a network, especially when combined with air quality modelling, is able to track the movement of pollution, and to help with source attribution.”

In addition to urban managers and planners there are many other stakeholders with an interest in air quality. For example, individual citizens may need localised data if air quality affects their health, or schools may wish to understand air quality during drop-off and pick-up to ensure that children are not adversely affected by pollution. Smart air quality monitoring networks can therefore provide information for all stakeholders to help in the overall goal of improving air quality. 

Hyperlocal monitoring data is made possible by Vaisala’s air quality monitoring system; not just because of their compact size and flexibility, but also because the capital and operational costs are substantially lower than traditional reference stations, which means that they can be deployed in higher numbers. Dense networks of compact air quality sensors will bridge the gaps between sparse monitoring stations and help to create a more complete picture of air quality.

Looking forward, as these compact sensors are rolled out more extensively, citizens will be able to use air quality data more frequently in their daily decisions, such as how to travel, when and where to exercise, which school to choose, and even where to live.

Recognizing the importance of compact AQMS data

It is clear that there are enormous benefits to be gained from networks of compact air quality sensors. These stations do not deliver ‘absolute’ data. Instead they provide a great opportunity to better understand trends and the spatial/temporal distribution of pollution.

Summarizing, Hannamari Jaakkola says: “The EU Directive for Ambient Air today recognizes and allows the use of “Indicative Measurements” by compact sensors. We very much hope that regulatory authorities around the world will recognise the vital and cost-effective role that the compact sensors will play in tackling air pollution; working in tandem with, and enhancing the value of existing reference AQMS to develop more accurate and effective models.

“Hyperlocal monitoring of this nature, coupled with meteorological measurements, are starting to form an essential component in the development of smart cities; providing crucial data for real-time traffic control and urban planning, for example. We are therefore delighted to be working with Lahti to better understand air quality in the city, and we hope that this project will serve as a high profile reference to demonstrate not just the benefits of monitoring, but also the advantages of the latest compact, flexible, wireless air quality monitoring technology.”