Air quality
Is the air getting cleaner?
Loading hourly readings from the Leeds Centre monitoring station…
Legal air is not the same as healthy air
Average concentration each year at Leeds Centre, in µg/m³. Dashed lines are UK legal limits; dotted lines are the World Health Organization's 2021 health guidelines, the level below which no meaningful harm is expected.
Pollution keeps office hours
Nitrogen dioxide by time of day, averaged over recent years. The two peaks are the morning and evening rush hours. Most of this pollutant comes out of exhaust pipes, which is why it tracks the traffic on the getting-around page.
Winter smog, summer ozone
Average concentration by month of the year. Nitrogen dioxide and particles build up in cold, still winter air; ozone is the opposite. It forms in sunlight, so it peaks in spring and summer.
Bad-air days are getting rarer
Days each year when coarse-particle (PM10) pollution averaged more than 50 µg/m³, the UK's daily limit, which the law allows on up to 35 days a year. Leeds Centre has stayed inside that allowance in every year on record.
Source: DEFRA UK-AIR hourly measurements from the Leeds Centre monitoring station (national Automatic Urban and Rural Network, urban background site). Readings to —. Last updated —.
Leeds Centre measures the general "background" air of the city centre, away from the kerbside, so air next to busy roads is worse than these figures. Annual averages only appear for years where the monitor captured at least 75% of hourly readings, which also excludes the current year until enough of it has been measured. The most recent readings are provisional until DEFRA ratifies them. UK legal limits come from the Air Quality Standards Regulations 2010. The World Health Organization's 2021 guidelines carry no legal force.