London's air-quality context

London's outdoor PM2.5 sits consistently above the WHO 2021 guideline of 5 µg/m³ annual mean. NO₂ from diesel traffic remains elevated along major corridors despite ULEZ. Both pollutants infiltrate buildings through windows, doors and envelope leakage, often dominating indoor exposure for occupants near busy roads.

The capital's building stock spans Victorian terraces with high infiltration, post-war commercial blocks with under-performing ventilation, and modern sealed buildings where mechanical strategy is the only path to acceptable air.

Building-type risks

Period residential. Damp, condensation and mould driven by post-retrofit air-tightness without commensurate ventilation upgrade. Humidity & health →

Commercial offices. Under-ventilated meeting rooms, drifting AHU controls, dirty filters and recirculation-dominant strategies. Office air quality →

Schools and nurseries. Roadside PM2.5 and NO₂ infiltration; classroom CO₂ regularly above 1500 ppm in winter.

Practical recommendations

Pair envelope sealing with mechanical ventilation and ePM1 50% (MERV 13) or higher filtration. Avoid opening windows during traffic peaks on roadside elevations. Add continuous PM2.5, CO₂ and humidity monitoring to verify performance — assumptions about London air rarely match measurements. IAQ monitoring →

Services we cover across London

We deliver IAQ testing, VOC and mould investigation, ventilation assessment and ongoing monitoring across central London, the inner boroughs and the wider M25 catchment. Same-week site visits for urgent cases, full reports against WHO, BS EN 16798-1, WELL and BREEAM benchmarks.

Indoor Air Quality in London: Risks, Standards and Services

London's air-quality context

Building-type risks

Practical recommendations

Services we cover across London

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