Organisations		PM2.5	PM10	NO2
WHO Air Quality Guidelines 20213	Annual	5 µg/m3	15 µg/m3	10 µg/m3
	24-⁠hour mean	15 µg/m3	45 µg/m3	25 µg/m3
UK Air Quality (Standards) Regulations 20104	Annual	25 µg/m3	40 µg/m3	40 µg/m3
	24-hour mean	-	50 µg/m3 (no more than 35 exceedances in a single year)	200 µg/m3 (1-hour mean) (no more than 18 exceedances in a single year)