There are different emission standards around the world, setting specific NOx emission limits that require the use of SCR and AdBlue. The four main pollutants covered by vehicle emission legislation are Oxides of Nitrogen (NOx), Particulate Matter (PM), Carbon monoxide (CO), and Hydrocarbons (HC).
In Europe, the first of these Standards, Euro 0, came into effect in 1990 with NOx limits of 14.4 and PM limits of 1.1, both measured in g/kwh. The 2001 Euro III standard reduced these limits to 5 and 0.1 respectively. The use of AdBlue came with the introduction of Euro IV, V and VI standards. NOx, particulate matter (PM), hydrocarbons (HC) and carbon monoxide (CO) are the components regulated. Euro IV was implemented from Oct. 2005 to Oct. 2006 and Euro V implementation dates were from Oct. 2008 to Oct. 2009. The Emissions limit for NOx is 3.5 g/kWh in Euro IV and 2.0 g/kWh in EuroV. Euro VI standard will be implemented as from 2013-14 and will have a NOx limit of 0,4 g/kWh.
In the USA, emissions from vehicles are regulated by the Clean Air Act. The use of urea SCR NOx control is coming to the US with the implementation of the so-called US2010 emission standard, which is effective as of January 1st 2010 and sets the NOx emission limits at 0,3 g/kWh.
In Australia and New Zealand, the emission standards follow those of Europe with a few years delay. Euro IV was phased in from 2007 and Euro V will be implemented in 2010.
In China, the legislation is called National Standard IV and V. From 2008, National VI standard for heavy duty vehicles has reduced NOx limits to 3,5 g/kWh and PM limits to 0,02 g/kWh. This standard has been applied in Beijing since 2008.
In Brazil, the legislation is called PROCONVE - Programa de Controle da Poluição do Ar por Veículos Automotores and will be applied as from 2012. The reagent in Brazil is known as ARLA 32 and this acronym stands for Agente Reductor Liquido Automotivo.