Improving ambient air quality is core to the mission of local decision makers: it is both a public health and environmental issue. The challenge is quite a tall order: outdoor air pollution causes millions of premature death worldwide, and in 2021, 91% of the world population is living in places where the World Health Organization (WHO) air quality guidelines levels are not met¹.

Finding ways to tackle this issue seems relatively complex: pollution sources and their associated impacts are localized, but very diverse. Fortunately, local decision makers can rely on tighter regulations, cutting-edge technological sensors which facilitate measurement, and inspiring best practices all around the globe.

How to tackle a global environmental and health issue and improve air quality in cities?

Regulation increases as scientific knowledge develops

Efforts to regulate ambient air quality are nothing new

The LRTAP² convention (1979) was ratified by thirty-four countries across Europe and North America. Along with its follow-up protocols, including the Gothenburg Protocol (established in 1999 and revised in 2012), this treaty is a landmark international agreement which paved the way to regulating air pollution globally and domestically. The convention put scientists and policymakers in the same room and delivered undeniable effectiveness³. 

The Gothenburg Protocol led the European Ambient Air Quality (AAQ) Directives (2004/107/CE, then 2008/50/CE) which set binding objectives and define specific responsibilities for European Union Member states to monitor, report on and manage air quality⁴. 

In North America, the protocol only reaffirmed existing regulation. The United States sets limits on air pollutants under the Environmental Protection Agency’s (EPA) Clean Air Act⁵, which celebrated its 50th anniversary in 2021. States are required to adopt enforceable plans to meet National Ambient Air Quality Standards (NAAQS) defined at the federal level. The need to implement air-permitting programs at the state level drives ongoing regulatory activity. The United States has also been collaborating with Canada since 1991 under the Canada-U.S. Air Quality Agreement (AQA) to address transboundary air pollution, especially acid rain and ground-level ozone⁶. 

Despite overall climate policy uncertainty, regulation is on the rise

In september 2021, the WHO drastically updated its air quality guidelines levels for main air pollutants⁷. As they serve as a reference globally, these changes should lead governments to update outdoor air quality domestic values and legal standards. 

In addition, despite mixed reactions around the COP 26 agreement among the scientific community⁸, climate commitments are on the rise⁹. Net-zero pledges and air emissions reduction targets translate into national strategies and drive an increase of regulatory binding measures. 

In North America for instance, air emission management framed the second-most common type of regulatory developments¹⁰. The European Union, which aims for climate neutrality by 2050, has 31 ongoing infringement procedures against 18 member states for failing to implement air quality rules domestically¹¹. 

Beyond compliance: air quality best practices are flourishing in cities all over the globe

Local and targeted answers to a global and complex issue 

Urban planning decisions made by mayors and local policy makers are a key enabler in the fight against air pollution. Outdoor air quality needs to be integrated into land use policies and documents, spanning a wide range of topics: transportation and mobility, urban infrastructure and ecosystems (smart buildings, vegetation buffers, etc.).

Improving air quality in the city is not limited to municipalities themselves. Decisions from the private sector have direct influence on how the issue is being addressed locally, either driven by regulatory pressure or voluntary. From global coalitions such as the recently announced Alliance for Clean Air¹²  to individual businesses integrating air quality to their management scope (through ESG / sustainability program or ISO type certification for instance), initiatives are spreading.

Activities from citizens matter, too. In Massachusetts for instance, activists are pushing for a new legislation to renew air quality monitors in order to better understand and combat pollution at the local level¹³.

"Urban Pedestrian Zone": how cities are acting locally to reduce air pollution from transportation?

Urban traffic is one of the main sources of ambient air pollution. The rise of urban pedestrian zones or zero-emission areas in European cities is a good example of how local action can be efficient. 

Driven by compliance, local authorities - and mayors in particular, are leveraging regulatory requirements as a toolbox to progressively tax or ban the most polluting vehicles, along with making cleaner transportation options safer, cheaper and easily accessible for residents (developing walk and bike lanes, prioritizing electric vehicles, making public transportation free or cheaper, etc.). These incentives help limit the concentration of air pollutants downtown, such as NO₂,PM₁₀/PM_2.5.

Urban pedestrian zones started in Sweden in 1996 and are now spanning over 230 cities in Europe including London, Amsterdam, Barcelona and Paris. They are also emerging out of the old continent. Seattle, for instance, announced the implementation of its first zero-emission area in summer 2022¹⁴.

Monitoring outdoor air quality to support decision making

The importance of a local diagnostic

How mapping urban air pollution used to be a complex endeavor?

Air pollution comes from a mix of different sources. Its impacts are hyper-local, they vary over the course of a day and from one city block to the other.

Understanding air pollution requires both to identify the different sources of pollutants in ambient air, as well as their concentration levels. This dual analysis helps understand how communities are being exposed in each urban area and pinpoint pollution hotspots.

Understanding the baseline situation by mapping urban air pollution is essential for local decision makers to understand pollution-related challenges and lead evidence-based urban planning. 

Until recently, the extent and quality of analysis have not always been granted. Conventional reference stations deployed in cities are big in size, complex to manage and costly, limiting their density and to the same extent the precision of local diagnostics. 

Things are changing: capturing and processing air quality data is now accessible

New generation connected air quality monitors, fixed or mobile, are a game-changer. Solutions developed by Ecomesure deliver accurate hyper-local air quality data, as the sensors they integrate follow a controlled calibration process, automated and strengthened by the application of artificial intelligence models. These compact monitors are complementary to existing instruments and often supplement them, enabling greater density of outdoor air quality data and real-time insight on pollution patterns within the city. 

Air quality data can be combined with other sources, such as peak road traffic and types of circulating vehicules,to provide municipalities with a better understanding of air pollution challenges and support their decision making process with stronger insight. This is what the local council community of Versailles Grand Parc is doing in France.