PM2.5 and O3 act synergistically

National and international organisations currently regulate and measure each pollutant independently.
But actually the bad effects don’t just add. A study of daily deaths in 372 cities found that the bad effects of fine particulate matter PM2.5 and ozone multiply up. Especially in high latitude regions (arctic and antarctic), and during the cold season.

The links between PM2.5 and O3 are synergistic, which means that there’s more than addition – it’s more like multiplying. 

As climate chaos extends, there are hotter days and more ozone.
Really importantly, some people and some areas are disproportionately affected by poor air quality. Some of those areas may have increased local ozone production – making it all even worse!

Here’s what the commentary says: “Regulatory standards still rely on geographic averages, rarely accounting for this unequal burden of exposure, let alone synergistic effects. Through the intersection of existing inequalities in health, structural racism, and other forms of discrimination, climate change therefore acts as a threat multiplier, exacerbating existing drivers of poor health for the world’s most vulnerable populations.”

Its an especial issue in the UK – where the regulations say its ok to have air four times dirtier than in the world health organisation targets. And the government is busy backpedalling on net zero

So what to do?

First, lets keep arguing on regulation. And for regulation which follows the science of synergy.

The commentary says: “clinicians, patients, and populations urgently need to implement evidence based interventions to reduce personal risks from air pollution, such as refraining from strenuous outdoor exercise when air quality is poor, monitoring heat and air quality, staying indoors with high efficiency particulate air (HEPA) filtration systems, using N95 respirator masks, and more. Clinicians and other healthcare professionals across specialties need to equip patients and communities with these protective physical, behavioral, technological, and pharmacological interventions and identify patients at high risk owing to pre-existing respiratory and cardiovascular disease, age, pregnancy, low paid (or no) employment, and poor housing”

Is it useful to know how PM2.5 and O3 specifically interact? Simple multiplication? Or …? 
Or are the differences between individual susceptibilities more important?!

More immediately: 

> Can the multiple experts sharing advice on air quality and activity explicitly factor in ozone?

> Can Breathe London with our monitor network, think about ozone – and not just PM2.5 and NO2?

> What about Airspace – who are already monitoring ozone? Is that factored into their AI?

> Right to know aims to give a “more accurate health risk narrative, particularly for vulnerable populations”, by averaging out results from the top 10% worst results – but have they factored in ozone?

And lets not forget indoor air pollution!

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