In addition to particulate matter emissions, a threat is also posed by emissions from ozone precursors - hydrocarbons and nitrogen oxide - on which further limitations are introduced under the Euro 5 standards.
Turklāt papildus vielu daļiņu emisijai draudus rada arī ozona prekursoru— ogļūdeņraža un slāpekļa oksīda emisijas, kurai lielāki ierobežojumi tiek ieviesti ar Euro 5 standartiem.