Air quality is a major issue in most large cities worldwide, but it also impacts on the surrounding rural and peri-urban areas. Rapid industrialization, private transport and residential heating are the main culprits behind the decrease in air quality recently registered by the World Health Organization (WHO).

Over 80% of people living in urban areas that monitor air pollution are exposed to air quality levels that exceed the WHO limits. According to the latest urban air quality database, an astounding 98% of cities in low- and middle income countries with more than 100.000 inhabitants do not meet WHO air quality guidelines.

When it comes to our air, what happens at ground level and what happens in the upper atmosphere are connected and should be addressed in a complementary way.

As the Climate Clean Air Coalition (CCAC) has pointed out, the work of reducing short-lived climate pollutants (SLCPs), among which the infamous PM2.5 and PM10 (organic particles, or particulate matter measuring between 2.5 and 10 microns in diameter), is complementary to the effort to reduce carbon dioxide (CO2).

SCLP mitigation has shown to have a significant potential to reduce near-term (20-40 years) global warming. It also prevents millions of premature deaths from small particulate pollution.

Combining SLCP and other greenhouse gas (GHG) emissions reduction efforts in cities can have co-benefits in terms of air quality. This is an approach ICLEI recommends to local governments – integrated efforts that offer a win-win solution to the community. In fact, 43% of the over 6,200 actions registered by cities in the carbonn Climate Registry, are reported as positively improving air quality.

So, here are five examples of cities that have been very successful in reducing their air pollution levels, sharing a brief peek at what they are doing to mitigate climate change, clean up their energy and transport sector and build resilience.

1. Vitoria-Gasteiz, Basque Country, Spain (-63%)
The municipality of Vitoria-Gasteiz has worked to improve the biodiversity and the urban landscape, by creating a “green belt” along the Avenida de Gasteiz. The city has already planted 33,000 plants of 70 different species and aims to plant 250,000 more, covering a total of 51 spaces with no or hardly any tree cover.
They have also developed a Public Space and Mobility Plan that fosters the use of public transport and bikes. Private vehicles use fell from 37% in 2006 to 24% in 2014.
Finally, the city has awarded €4.6m in grants for the refurbishing and retrofitting of old houses. Over 10,000 renovations were carried out, mainly improving the insulation and energy performance of the buildings.

2. Montréal, Canada (-54%)
Montréal’s emissions fell by 54% between 2008 and 2013.
The city boasts many parks and waterways. Several projects were launched to preserve and expand the tree cover of the city to improve air quality and urban biodiversity.
A series of projects targeting the use of fossil fuels for transport were also undertaken, for instance aiming to ensure that at least half of the city’s taxi fleet are electric-hybrid vehicles.

3. Lisbon, Portugal (-50%)
In 2008 particulate matter had an annual mean of 30 ug/m3 (micrograms per cubic meter of air) in Lisbon; in 2014 that figure had become a 15 ug/m3.
Lisbon used electric mobility to shift transport from private to public and from brown to green. Showing leadership, the city has also undertaken a large project for electric mobility, installing in its first phase 514 charging stations to incentivize the use of electric vehicles by private citizens.
The municipality has cut in half the number of its own operational vehicles, down to 381, and acquired 54 electric cars, reducing both costs and emissions for governmental operations.

4. Medellín, Colombia (-33%)
Medellín cut its PM10 by a third, from 68 ug/m3 (2007) to 45 (2014) ug/m3. There’s still much to be done, as the WHO guidelines for PM10 recommend an annual mean of 20 ug/m3, but the improvements are dramatic.
Medellín reported almost 40 projects with air quality co-benefits to the carbonn Climate Registry. Among them: the creation of a Green Metropolitan Belt; the introduction of a Bus Rapid Transit system that reduced GHG and other pollutants, including PM10, NOx and sulphur dioxide; reforestation, bike sharing and car sharing projects.

5. Seoul, Korea (-28%)
A mix of sustainable transport, renewable energy and energy savings is the avenue the Seoul Metropolitan Government decided to take to improve air quality while saving resources and reducing GHG emissions. More than one sixth of Seoul’s population – around 1.7 million citizens – joined the Eco-Mileage System, a program providing incentives based on the amount of energy saved.
Since 2002 the city has also made substantial efforts in curbing both GHG and SLCP emissions of the transport sector. Some of the measures taken include: incentives for the replacement of over 265,000 diesel engines with LPG ones in private vehicles, tripling car-sharing to 1,500 units and expanding the public transport network to 117 km.
In order to protect the vulnerable sections of the community from air pollution, Seoul also issues air pollutant forecasts and alerts directed at 4018 education offices and schools, 4500 senior centers and 662 care centers for senior citizens. The information is released on a real-time basis via website, electric display boards and mobile apps.