Particulate Behaviour

Fade In:

People wearing masks

Ride their bicycles through

A skyline of exhaust fumes and

Dirty, blackened smoke.

Their lungs irritated

By the invisible particles that corrode

Metal frames and

Alveolar walls.


Go their bells as they

Cross the road and

Casually turn right

Into the unmarked bloodstream.


Fade In:

A sickly orange sun

Climbs above the

Rigid concrete monoliths;

Grubby metallic fingers that

Cast a shadow

Over streaming crowds,

As a filthy fog


Over a city

Where Angels now fear

To tread.


Fade In:

Automobiles find that they have

Been cast as ‘Unwanted guest #3’,

Whilst smutty furnaces

Spew out their final

Lewd gestures to a hazy

And judgmental sky.

In amongst the bathwater

A grimy sponge is washed away,

Leaving only the fragrance of a

Thousand burning photocopiers

To sate the billions of goldilocks

Who wait for things to turn out right.


Fade Out.

Forbidden City under the pollution of present-day Beijing.

This science poem is inspired by recent research which has found that China’s massive reductions in particulate air pollution are also bringing about an increase in ground-level ozone pollution.

Since 2013, the Chinese government has systematically tried to reduce the amount of fine particulate matter (PM 2.5) that is prevalent in many of their major cities. Measures such as restricting the number of cars and replacing coal-fired power plants with natural gas have seen PM 2.5 concentrations in eastern China drop by over 40% in just five years. However, this has also had an unforeseen, and dramatic, effect on the amount of ground-level ozone, a harmful atmospheric pollutant that causes both smog and severe respiratory problems.

Whilst PM 2.5 is itself a harmful atmospheric pollutant, this recent research has been able to show how it plays another important role in atmospheric pollution: acting like a sponge for some of the chemical radicals (molecules that contain at least one unpaired electron, and are thus more reactive) that are needed to generate ground-level ozone. This means that as levels of PM 2.5 have decreased over eastern China, the levels of ozone have increased. The fact that this PM 2.5 reduction has happened over such a dramatic timescale in China (it took the US over 30 years to accomplish what China has managed in just five) has enabled researchers to better understand this relationship. Decreasing this ground-level ozone in the future will require new emission controls to overcome this recent reduction of PM 2.5 and its effects on atmospheric chemistry.

You can listen to an audio version of this poem here:

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