In 2012, 2.6 million people died as a result of outdoor air pollution exposure. This is not a phenomenon limited to Asia or Africa.
More than 75 per cent of Europe's urban population was exposed to air pollution concentrations above the WHO guidelines for the protection of human health.
Climate change poses a threat to our world, increasing temperatures and shifting seasons. Some types of air pollution are even predicted to worsen under a changing climate. But that doesn't need to be the case, there is hope.
Not only am I optimistic following last December's COP 21 agreement, but if air pollution and climate change mitigation actions are coordinated, then there are a number of potential win-win options.
However the flip side of this is that if we continue along a more traditional siloed approach, addressing the issues separately, we will likely set ourselves back to implementing policies that lead to progress in one area, but not the other.
Have you ever stopped to consider what exactly comes out of your car's exhaust or from the smokestack of a power plant? Not just generally, but more specifically what all these emissions are actually composed of?
A large number of emission sources include a variety of air pollutants, such as nitrogen oxides, volatile organic compounds and particulate matter, including black carbon.
And they also emit carbon dioxide - the most important greenhouse gas and the major culprit behind our warming climate.
Because many of the same sources emit both air pollutants and greenhouse gases, it would be logical to consider how the mitigation measures we apply or the alternatives we promote might affect not only their CO2 emissions, but also their other emissions, such as air pollutants.
Take for example residential heating using wood or other biomass. This is often marketed as a ‘green’ technology and climate friendly - because overall, CO2 emissions are typically lower compared to heating provided by fossil fuels.
However, residential wood combustion is along with diesel engines in the transport sector, among the two largest sources of black carbon emissions in Europe. So although net CO2 emissions may be less, significant amounts of air pollutants are still emitted.
Black carbon is of significant concern because the dark colour of these particles absorb incoming and outgoing light (solar radiation), thus contributing to warming.
Other components of particulate matter can be lighter in colour, scattering light and therefore exerting a cooling effect. Ozone is also a greenhouse gas that contributes to warming.
Because of the shorter lifetime of air pollutants in the atmosphere (they either naturally fall out of the atmosphere or deposit themselves on surfaces, get rained out, or undergo chemical transformations) their effects tend to be more regional and closer to their emission source.
In comparison, the longer-lived greenhouse gases such as CO2 (around 100 years or more in the atmosphere) are mixed up across the world, and therefore have more global implications.
Additionally, studies show that climate change also impacts on air pollution. Warmer temperatures are strongly correlated to higher ozone concentrations and changes in precipitation patterns influence particulate matter concentrations.
However on a more positive side, there are plenty of mitigation options that are great for both air pollution and climate change.
For example, improvements in energy efficiency and renewable energy sources such as wind and solar power, or changes to urban and long-distance mobility that shifts usage away from individual conventionally fuelled vehicles to more environmentally friendly options, such as sustainable public transport, cycling and walking.
Such options clean our skies of air pollution and reduce our CO2 emissions.
We need to work not only on individual behaviour and quick fixes, but collective behaviour change and sustainable, long-term solutions.
Recognising the win-win options when assessing the connection between air pollution and climate change is a great step in the right direction.