How air quality and weather data help cities boost resilience

Resilience, climate adaptation and sustainability are topics that have edged themselves to the very top of the agenda for cities around world and increasingly resonate with every city department. Central to the discussion is, of course, the fight against climate change but such topics are also key to addressing a number of other critical challenges cities are facing, such as poor air quality, pollution, congestion and reliance on fossil fuels. And these will only worsen if not tackled head-on today.

According to the United Nations (UN), by 2050 two out of every three people will live in urban areas and the combination of demographic shifts and population growth could add around 2.5 billion people to the world’s overall population. The UN also projects that by 2030, the world could have 43 megacities of more than 10 million inhabitants, most of them in developing countries.

This all adds up to a huge amount of pressure on cities’ resources and services, compounding existing problems and no doubt creating new ones, which will have a detrimental effect on the quality of life of citizens as well as the environment and planet.

The emergence of compact air quality sensors more than 10 years ago has provided cities with a lower cost complementary tool to measure hyperlocal air quality

Indeed, there are few more basic human rights than being able to breathe clean air but, according to the World Health Organisation (WHO), almost the entire global population (99 per cent) breathes air that exceeds its air quality limits and the problem is worse in low- and middle-income countries.

Exposure to air pollution is estimated to cause seven million premature deaths every year. WHO issued even more stringent Air Quality Guidelines (AQGs) in September 2021, recommending air quality levels for six pollutants including particulate matter, ozone, nitrogen dioxide and carbon monoxide. The AQGs are designed as a tool for policymakers to guide legislation to reduce the levels of such pollutants.

Its negative impact on health is reason enough to take steps to improve air quality but measures in this area also cut across other strategies and projects that fall under the resilience and sustainability banner such as smarter mobility, cleaner energy and greener buildings. Indeed, as we will explore in this Special Report, to improve air quality is also to mitigate climate change, build resilience and ultimately help to futureproof cities. This relies on cities not just measuring air quality in isolation but understanding what influences it, how, why and when it changes and, crucially, the part weather plays in it. And this all begins with data collection.

Air quality sensors, data collection and urban integration

Historically, air quality has been measured with air quality monitoring stations which use refined analyser technologies and calibration methodologies. This means they are extremely accurate but also expensive. Moreover, their size and cost means they tend to be installed in small numbers in limited locations rather than as networks.

The emergence of compact air quality sensors more than 10 years ago has provided cities with a lower cost complementary tool to measure hyperlocal air quality. They have emerged after two key sensing technologies reached maturity for field use: amperometric electrochemical sensors for detecting gaseous pollutants in parts per billion (ppb) levels, and compact optical particle counters for detecting particles in the micron/submicron size range.

Initially, there was a trade-off in their more limited measurement performance, especially in extreme conditions, but researchers and manufacturers worldwide have worked hard to improve their performance. Today, the sensors are sensitive enough to detect the pollutants even in clean ambient air, which can give users confidence in their ability to determine transitions from clean air to moderately to heavily polluted conditions.

It is their ability to be deployed in dense, wide-area networks that complement traditional air quality reference networks that makes them eminently suitable to be deployed in urban environments. Importantly, when weather stations are added to such networks to provide information on meteorological conditions – like wind speed and direction and precipitation – it provides a far fuller picture of the quality and movements of urban air.

“People are starting to understand the concept and value of a smart pole as the digital backbone of the smart city and which creates new data-driven services for cities”

For example, Vaisala’s air quality sensors and weather stations are deployed around the world and the data collected by them is playing a vital role in many smart city projects. Typical use cases include traffic management, street dust monitoring, pollution hotspot detection, near source monitoring (such as on urban industrial estates or even around a school at specific times like drop-off and pick-up), community monitoring as well as health and wellbeing programmes.

Data from such networks becomes even more powerful though when integrated and cross-referenced with that from other sources, such as from traffic departments, private and public transit providers and healthcare organisations.

There remain challenges though to establishing such networks, such as connectivity and interoperability. The sensors need both power and connectivity for data transfer so we are increasingly seeing them deployed on smart city infrastructure as well as mobile phone network stations (both 4G and 5G).

A consortium led by Nokia with partners that include Vaisala, Destia, Premix, Indagon, Rumble Tools, Orbis, Tehomet, Teleste, Spinverse, Tampere and Aalto Universities and the Technical Research Centre of Finland) goes a step further and shows how smart poles can be used as the underlying infrastructure for such networks and the host of a range of other devices and technologies. Moreover, the LuxTurrim5G ecosystem project set out to create a pilot environment to demonstrate the development of data-driven services for cities in Finland and abroad.

Covering an area from the Nokia headquarters campus in Espoo to the nearby Kera railway station, it comprised 19 smart poles with 5G base stations for connectivity and 250 interconnected devices to create an extensive sensor network. The smart pole is also equipped air quality and weather sensors from Vaisala and others, video cameras, radar devices, (including lidar), information screens, plus an electric vehicle charging point, and a drone charging and landing station at the top of the pole.