The Ultra Low Emission Zone has cut roadside NO2 by pricing out the dirtiest diesels — a real win. But ULEZ does far less for PM2.5, the fine particulate most tied to health harm, because a lot of PM2.5 comes from tyre and brake wear, wood burning and sources drifting into London from outside.
Ready to clean up your London air?
Luggable MERV-13 kits deliver up to 681 m³/h CADR — built on the Corsi-Rosenthal principle, from £229. Ships from Oxford in 2–3 days.
Shop the UK store → See all kitsWhat ULEZ improves
Nitrogen dioxide at the roadside, most noticeably on the busiest corridors. If NO2 is your concern — you live on a main road — the trend is in your favour.
What it doesn't
PM2.5 stays stubborn. That's the particle a home purifier is best at removing. Whatever ULEZ does outdoors, a high-airflow MERV-13 kit keeps indoor PM2.5 low — which is where you spend most of your time.
Frequently asked questions
Does ULEZ improve the air in my home?
Indirectly and partially — it lowers roadside NO2 but does little for PM2.5. Indoor filtration is the reliable way to cut the particle load where you live.
Is PM2.5 affected by ULEZ?
Only modestly. Much PM2.5 comes from tyres, brakes, wood burning and out-of-city sources that ULEZ doesn't target.