Why do we need continuous, real-time air quality monitoring in London?

Because you can’t manage what you don’t measure.  And today, air quality monitors are sparse & expensive (only 85 official stations in London monitoring NO₂ and only 15 monitoring PM_2.5), not real-time, and data output is mostly based on historic averages.   99.999% of the reported data points are calculated, not from real (or real-time) data, resulting in spatial & temporal variability not being captured (e.g. ‘hot spots’). Therefore derived parameters (e.g. personal pollution exposure) are unreliable or inaccurate.  Or to put it another way, half of London could be on fire and we wouldn’t know.

If we’re going to improve health outcomes for millions of Londoners – and any city for that matter – we clearly need better monitoring, to provide more accurate data in the here and now.  There are therefore three key features that monitoring needs to have:

1. Granularity – thousands of monitors – because air quality varies greatly over short distances – even across a road

2. Continuous operation – because air quality also varies greatly from one minute to the next, driven largely by weight of traffic, but also by wind speed/direction, etc.

3. Real-time readings – if data isn’t in or near to real-time, you can’t take appropriate action (alerts to help people avoid it for example)

But does better measurement actually help?  How does knowing more help?  It’s the first step, without which you can’t take the vital next steps:

– Avoidance – Reducing the impact on public health, by helping people reduce their exposure to poor air – e.g. through low-pollution route planning apps, because you know and can short-term forecast where that bad air is

– Mitigation – the data will show how and where to apply new technologies, rules or policies

Because – and this is important – air quality in London isn’t ‘just bad everywhere’ – it varies considerably from area to area, street to street, both short-term and long-term.  Perhaps if people understood that, they would really start to agitate to have access to real data.

Why isn’t the government doing this properly?  First, because they’re scared of what knowing the answers would mean – pressure to take action (involving the road lobby, black cabs, etc.).  Second, because of a lack of political pressure – there aren’t any votes for or against it because the public isn’t engaged. Air quality is where smoking was in the 60s – the public hasn’t been aware even though the experts know the dangers.  But hopefully that’s changing through the Evening Standard and Sunday Times campaigns, and of course Dieselgate.  The VW scandal has focused quite a bit of attention on air pollution – and this story will run and run as more car companies will be found out, and fines (at least in the US) will follow.

What could we do with better monitoring and therefore better, real-time data?  There are many techniques and technologies that pertain to improving air quality, but here are just some examples:

– Localised alerts to protect everyone, especially vulnerable groups (e.g. asthmatics) through apps & text messages

– Pollution avoidance route planning for pedestrians and cyclists through existing route planning apps

– Better transport planning – with better, long-time data, city and transport planners would have the planning input they need for everything from changing bus routes to pedestrianisation

– Hot spot reduction through (for example) variable traffic light phasing

– Passing prompts to hybrid vehicles – particularly buses – to switch to electric operation when in pollution hot spots

– Using data to control air conditioning unit filters, to save energy

It’s time to start monitoring air pollution properly.  Let’s get on with it.