5. Pollutants. 5.4. Motor vehicle emissions.

Level of recommendation	Statement
A	Background: Exposure to nitrogen oxides, ozone, and particulate matter with a particle size of < 2.5 µm (PM 2.5) is associated with an increased risk, especially for asthma.
	Recommendation: Exposure to vehicle emissions should be kept low. (A)
Level of evidence	Deng 2016 (2+); Brunst 2015 (2++); Gruzieva 2013 (2+); Hasunuma 2016 (2+); Hsu 2015 (2–); Molter 2015 (2++); Nishimura 2013 (2–); Rancière 2017 (2++); Ranzi 2014 (2+); Tétreault 2016 (2+); Kathunia 2016 (not rateable)
Level of consensus:	Strong consensus