Exposure to fine particulate pollution (PM2.5) could dramatically increase the mortality of COVID-19. A Harvard University study adds new elements to SIMA’s analysis.
Researchers from Harvard T.H. Biostatistics Department Chan School of Public Health investigated the hypothesis that the long-term effects of fine dust pollution (PM 2.5) could drastically increase the risk of death from COVID-19.
The assumption of the study is the significant overlap between the causes of death of COVID-19 patients and those of diseases related to long-term exposure to fine particulate matter (PM2.5). To test the hypothesis that particulates may exacerbate the severity of COVID-19 infection symptoms and increase the risk of death, researchers compared U.S. mortality and contagion data, filtered from the effects of many confounding factors[1], with long-term exposure (from 2000 to 2016) to PM2.5 air pollution.
The results of the document suggest that long-term exposure to air pollution increases vulnerability to COVID-19: an increase of 1 µg / m3 of PM2.5 would raise COVID-19 mortality rate by 15%.
The authors of the study cited Manhattan, current epicentre of the pandemic in the United States, as an example. In Manhattan, the PM2.5 values varied from about 7 to 11 µg / m3 in recent years and the reported deaths for COVID-19 until April 4th are 1904.
Researchers calculated that 248 fewer people would have died in the past few weeks if the particle levels kept an average only one unit lower over the past two decades.
But let’s focus on Italy and in particular to the area most affected by COVID-19, the Po Valley. In Lombardy, Emilia Romagna, Piedmont and Veneto there are 84.7% of Italy’s total deaths (of the 14860 deaths on April 6th ).
By analyzing the data of the Ministry of Health available on the site of Il Sole 24 Ore, it is possible to draw up a list of the most affected municipalities in terms of contagion.
| Municipality | Total cases | %cases/population |
| Cremona | 4489 | 1,251% |
| Piacenza | 302 | 1,052% |
| Lodi | 2376 | 1,032% |
| Bergamo | 10043 | 0,90% |
| Brescia | 10122 | 0,80% |
| Reggio Emilia | 3505 | 0,66% |
| Mantova | 2277 | 0,55% |
| Parma | 2421 | 0,54% |
| Lecco | 1805 | 0,54% |
| Pavia | 2889 | 0,53% |
| Alessandria | 2081 | 0,49% |
| Verbano C O | 774 | 0,49% |
| Rimini | 1613 | 0,48% |
| Modena | 2867 | 0,41% |
| Vercelli | 693 | 0,41% |
| Milano | 12479 | 0,38% |
| Monza Brianza | 3355 | 0,38% |
| Sondrio | 654 | 0,36% |
| Biella | 621 | 0,35% |
| Padova | 3134 | 0,33% |
| Novara | 1218 | 0,33% |
| Verona | 3049 | 0,33% |
| Torino | 6925 | 0,31% |
| Asti | 655 | 0,31% |
| Belluno | 620 | 0,31% |
| Bologna | 2856 | 0,28% |
| Forlì Cesena | 1081 | 0,27% |
| Como | 1605 | 0,27% |
| Cuneo | 1301 | 0,22% |
| Vicenza | 1885 | 0,22% |
| Treviso | 1906 | 0,22% |
| Venezia | 1751 | 0,21% |
| Ravenna | 751 | 0,19% |
| Varese | 1491 | 0,17% |
| Ferrara | 563 | 0,16% |
| Rovigo | 249 | 0,11% |
Among these, the province most sadly affected, especially for fatal cases, is that of Bergamo. In the city, deaths have almost quadrupled from an average of 110 cases in the years from 2015 to 2019 to 430 in 2020 (from February 24 to March 21).
As an exercise, I extracted the average annual, maximum and minimum daily values of PM2.5 pollution in the cities of Bergamo and Cremona from European Environment Agency’s (EEA) air quality databaese. The data are only available for the years 2013 to 2018.
| Bergamo | Cremona | ||||||
| year | Unit | Yearly average | Max daily level | Min daily level | Yearly average | Max daily level | Min daily level |
| 2013 | µg/m3 | 23.17 | 79.50 | 1.59 | 27.16095 | 126.0465 | 2.9866 |
| 2014 | µg/m3 | 20.20 | 89.00 | 2.00 | 25.28963 | 105.5542 | 3.07625 |
| 2015 | µg/m3 | 25.67 | 83.30 | 3.00 | 29.29249 | 131.0625 | 2.100833 |
| 2016 | µg/m3 | 22.07 | 114.40 | 1.30 | 25.50144 | 131.0625 | 1.7575 |
| 2017 | µg/m3 | 26.35 | 169.80 | 2.10 | 28.94044 | 157.1083 | 2.112083 |
| 2018 | µg/m3 | 21.33 | 78.00 | 1.00 | 23.38677 | 79.25909 | 2.777083 |
It would be very interesting to verify whether what emerges in the Harvard study, that’s to say that there’s a correlation between PM2.5 pollution and COVID-19 mortality, is also valid in our country.
In the meantime, an all-Italian research team has published in Environmental Pollution a scientific paper which confirms that the high level of pollution in Northern Italy should be considered a contributory cause of the high level of mortality recorded in the area.
Further proof of a decidedly evident correlation that remained only to be demonstrated through more solid scientific evidence. And I am sure that over time the evidence will be even more.
Also, an important warning to all of those believing it is possible, and indeed appropriate, that in the short term we should stick with fossil fuels or reduce environmental standards.
An example is the automotive sector. Recently a consultancy firm advised that industry should fall back on petrol and diesel cars and ask for reductions in car emissions’ targets. This to allow immediate profits for car manufacturers, soundly affected by the effects of the COVID-19 pandemic, allowing for future investments in electric cars.
Lowering environmental standards and reducing polluting emissions objectives is the worst possible answer to a crisis that has deep environmental roots.
It is up to all of us to prevent this from happening.
[1] Socio-economic, demographic, meteorological, behavioral and health factors that can influence mortality were considered and their importance was verified through a wide range of sensitivity analyzes.
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