ClairCity newsletter ClairCity newsletter May 2020 | Page 4
Conference update
It was with a heavy heart that we had to cancel
our conference in Brussels back in March. A lot of
work went into the preperations for this event and
many were looking forward to hearing our
findings and celebrating in our successes.
The team had secured a venue, confirmed speakers,
arranged accomodation and travel, prepared
communications materials, written presentations and
promoted widely. Yet all was not lost. Out of the ashes
comes our online webinar series and the hope of a
belated celebration after the end of the project and
after lockdown restrictions have eased.
We would like to take this opportunity to thank
everyone who was involved during this process, and
hope you can find some solice in the upcoming webinar
series!
Air quality news
Earlier this month the American Geophysical
Union’s journal Geophysical Research Letters
published two papers that take a look at the effect
of lockdowns on air quality - and the results may
not be what one might expect.
One of the studies supports claims that levels of
nitrogen dioxide and particulate matter pollution over
China, Western Europe, and the United States have
fallen dramatically due to lockdown measures. However,
the other shows levels of surface ozone in China have
increased.
The first paper drew of satellite measurement and found
that while results varied, most of the coronavirus
epicentres they measured showed reductions. For
example, NO 2
levels were down by 40% over urban
areas in China, 20% over Belgium and Germany, and
19–40% in different areas of the U.S. There was no
decrease in Iran however, and this is believed to be due
to a less stringent lockdown.
Experts have not observed reductions of such
magnitude since satellite-based air quality monitoring
began in the 1990s, according to Stavrakou.
The second paper focused on northern China,
measuring the levels of nitrogen dioxide, particulate
matter, and surface ozone after the lockdown began
on January 23, 2020. This time the authors reported a
60% reduction in NO 2
and a 35% reduction in
particulate matter. So far so good. However, secondary
pollutant surface ozone increased by 150–200%.
Surface ozone can cause “severe health problems,
including pulmonary and cardiac diseases,” state the
authors. A variety of household cleaning products and
paints, and industrial sources release volatile organic
compounds. And it is these compounds, when mixed
with NO 2
, that produce surface ozone. Sunlight and
higher temperatures create the perfect conditions for
this reaction to take place, so the change in seasons
may have gone some way to amplifying this situation.
Lockdown has offered scientists unprescedented
insight into the impact of emission regulations - a
silver lining during this tragic situation. Indeed,
our modellers throughout Europe have been doing
their own investigations and are in the process of
writing papers on these emerging dynamics. We
will update you when we have further details.
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