Drop in air pollution in Chiswick High Rd

Image above: Chiswick High Rd; photograph Joanna Raikes

The level of air pollution in Chiswick High Rd has dropped significantly, particularly in the last three months.

The pollutants NO2, PM10 and PM2.5, which have been clearly linked with damage to the heart and lungs, are monitored at a point on Chiswick High Rd. The data on NO2 and PM10 particulates has been collected since 2003 and the data on the more damaging PM2.5, since 2017.

Tom Pike, Professor in Electrical Engineering at Imperial College, London, who lives in Chiswick, has been doing some number crunching for The Chiswick Calendar and his findings are surprisingly positive.

Over the entire period from June 2017 till March 2021, air pollution levels have dropped by more than half. In the three months from December 2020 to March 2021, the fall in pollution was more than twice the average drop seen since the start of the pandemic. Since the beginning of the first lockdown, air pollution levels have been steadily falling.

Excess PM2.5 levels have dropped to their lowest recorded level. By ‘excess’ what he means is the amount recorded on the High Rd, compared with areas nearby which have relatively low air pollution levels (in this case a spot in North Kensington which is away from a major road).

Air pollution costs Chiswick 3% GDP

What has caused this is not entirely clear. In part it will be an overall reduction in the amount of traffic on the High Rd (for which we have Department of Transport data up to 2018). There has been a decrease in traffic by about 25% over 20 years. Each time there have been manual counts (in 2003, 2005 and 2018) the Department of Transport has found that traffic has fallen by about 10%.

Vehicle use has also dropped considerably during the pandemic, especially during the first lockdown. The reduction in use of diesel engines will also be a factor, according to Professor Pike, and perhaps the withdrawal of the 27 bus service in 2019. The introduction of the cycle lane may also be a factor, but it’s too early to tell, especially as the period since C9 was opened roughly corresponds with that of the third lockdown.

According to work carried out by his colleagues at Imperial, in 2019 there were 4,000 early deaths in London that can be attributed to our city’s pollution. As a comparison, COVID-19 has so far led to 15,000 extra deaths in London.

Ill health and early deaths from air pollution also have an economic cost, disproportionately so on London compared with other European cities, because it seems, a greater number of people who create more wealth have been harmed by pollution.

Professor Pike has worked out that the cost of air pollution to our local economy is 3% our local GDP. The drop in air pollution over the past three months, if it continued at that rate over 12 months, works out as a health-cost saving of £410,000 a year.

For a fuller explanation, complete with detailed data sources and graphs, see Tom Pike’s guest blog:

Pollution in Chiswick High Rd – what does the data say?

Read more stories on The Chiswick Calendar

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