In this episode of Roots & Rooftops, we sit down with Professor Frank Kelly at Imperial College London to explore the history of air pollution in London — and the biggest challenges ahead in making the city’s air cleaner and safer for everyone.

A leading expert in air pollution research, Professor Kelly reflects on the deadly Great Smog of 1952, explains why London has met its nitrogen dioxide (NO₂) legal limits earlier than expected (with two important caveats), and outlines what still needs to change for air quality to align with World Health Organization guidelines.

He also shares practical, everyday tips to improve indoor air quality, and a clear view of what citizens and policymakers can do next to improve London’s air overall.

Chapters
00:00 Intro + Prof Frank Kelly (Imperial)
04:03 The Great Smog of 1952: what it changed
06:50 The “trade-off” problem: fixing one pollutant, creating another
09:11 London meets DEFRA NO₂ limits — why that’s not the finish line
16:23 Wood burning: a growing source of pollution
19:00 Indoor air: the overlooked risk at home
20:47 What’s next for London’s air (and where progress may stall)
22:36 Microplastics from tyres: the next air quality frontier
24:09 Practical steps for cleaner air (at home + outdoors)    

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Music, mixing and mastering by Jo Elise.