Has air pollution reduced from Covid19 lockdowns? Reflections #26

Insight – Air pollution

I have read a lot of people recently talking about how clear our skies are, given how few cars there are on the road. Sydney has had some beautiful days lately. So are we managing to reduce pollution (and hence improve our chances if Covid19 gets out of control here)? Yes, we have, a bit, but looking at the data, this time of year is also generally a better year for pollution generally in Sydney (my theory, for what it is worth is that it is too late for bushfires, too early for burning off, and the winter temperatures lead to more inversion layers trapping pollution for a while).

I checked out this site, which was my goto site during the bushfires which seem a lifetime ago, but were still going when I first heard about Covid19. I looked at St Mary’s, in western Sydney. Because of the geography of Sydney, the west of Sydney often has more pollution than the east, as the geography traps pollution, with only a small escape route out to sea.

I’ve shown here the PM2.5 statistic daily (which is the really damaging measure of fine particulate matter) and also the NO2 measure. And while by eye the April lines for 2020 and 2019 look pretty similar, my calculations do show a material difference over the last month, particularly in the PM2.5 measure.

And why does air pollution matter? This article looks at the apparent correlation between polluted cities, and those worst hit by Covid19. As the article is careful to point out, correlation is not causation. It may be that those places worst hit by Covid19 are those with strong links to each other (perhaps through manufacturing clusters?) so they were the first to have outbreaks out of control. But given there is a well known link between many diseases, particularly lung diseases, and air pollution. In a different context, this report in NSW looks at the link between coal dust pollution and excess disease. So it is plausible that someone exposed to air pollution over many years might be more susceptible to a disease that attacks the lungs.

Link

I’ve posted before about how not all deaths are being counted in different places in the world. Today here are too more links illustrating the problem – The Economist looks across a number of different countries, and the UK Actuaries (continuous mortality investigation) are reporting weekly on the information from England and Wales. In my view it is probably doing the best analysis – it is correcting for the date of notification of deaths (to look at how many deaths might not yet have been notified each week – IBNR), and age distribution in the “expected” deaths in each week. In the week ending 10 April 2020, they estimated that there were around 8,000 excess deaths in England and Wales, compared with what you might expect based on underlying mortality. Their report says that up to 20 April 2020, their analysis suggests that there could already have been around 26,000 to 32,000 cumulative excess deaths in England & Wales, and a total of 28,000 to 34,000 in the UK as a whole. The official counted deaths by 20 April 2020 in the UK were just over 16,000.

Life Glimpses

When the lockdown started, I had been thinking that we were very lucky we were in an era of virtual books – if I need a new one (and I have been reading quite a lot of fiction) I can just download one. But some of the people in the house are quite enjoying the physical book, so we may have to go down the old fashioned route if we need a new one. While our local bookshop is somewhat open, it requires a bit of planning and ordering ahead to actually take delivery of a physical book.

Bit of Beauty

Our quest for the perfect cupcake continues – these probably look the best, but previous versions tasted better. They were still pretty delicious, though!