Air Quality and Automobile. Technological Solutions to Limit the Impact on Air Qality

Climate change and air quality are the two major challenges we face. In both cases, the transport sector, and the automotive sector in particular, is involved: on the one hand, it emits significant quantities of greenhouse gases (CO ₂ , CH ₄ , etc.) and on the other, it is one of the main sources of pollutants such as particulates but also and above all nitrogen oxides.

In the early 1990s, Europe decided to regulate emissions from the road transport sector. The first standard, called Euro 1 Euro x" standards were introduced in January 1993. Since then, the "Euro x" standards have continued to be tightened, leading automakers to reduce their vehicles' emissions of primary pollutants time and again. But while vehicle emissions and those from other sources have indeed been reduced, the results in terms of airborne concentrations are not always obvious:

• fleet renewal, which takes time and does not immediately show the effectiveness of new pollution control technologies;

• vehicle maintenance, which is not always provided by the customer;

• the multiple and not always traceable origins of pollutants and their processes of evolution in the atmosphere, depending on geography, meteorology or even the topography of the areas under consideration (cf. "wide avenue" versus "canyon street" i.e. narrow street lined with tall buildings).

That said, it is clear that today's air quality directives are increasingly influencing the development of emissions standards, which in turn will influence the development of tomorrow's pollution control systems. For example, the issue of diesel particulates has been addressed since 2011 ( Euro 5 ) thanks to the introduction of particulate filters or the generalization since 2014 ( Euro 6.b ) of SCR (Selective Catalytic Reduction), highly effective in reducing NOx emissions from diesel vehicles.

The aim of this publication is to draw a link between the changes in air quality in recent years, as described in detail at [BM 2 502] , and the progress made in the field of automotive emissions control, bearing in mind that this...