Northern Italy is steeped in air pollution: which substances cause it, the myths to debunk, and the solutions to address it, according to Arpa Lombardia.
The air we breathe has become a matter of growing concern; the enemy is insidious because it is often invisible, yet the damage it causes is plain to see: more than 52,000 deaths a year linked to pollution in the European Union alone. Northern Italy is currently blanketed in smog, with persistent dense fog and the formation of chemical snow, which forms when pollutant particles present in the fog freeze, giving rise to a kind of artificial snow. These conditions have serious repercussions for public health and the environment, highlighting the need to monitor air quality carefully and to adopt measures to reduce air pollution.
The Po Valley in particular is experiencing difficult days due to the formation of thick, persistent fog affecting especially the regions of Lombardy, Emilia and Veneto. In the provinces of Milan, Bergamo and Pavia, six consecutive days of exceedances of the permitted concentration limits for PM10 have been recorded, and temporary first- or second-level measures — including traffic restrictions — have also been activated in Lodi, Monza and Brianza, and Cremona.
Fortunately, more and more people are now aware of the pollutants contaminating the air we breathe, and of the measures to be taken, especially within urban centres, which have the highest concentration of pollutants: zero-emission zones, such as pedestrian or cycling areas; low-emission zones such as 30 km/h zones; the use of electric and shared mobility, zero-emission homes, and more extensive and efficient public transport networks.
Yet there is still a long way to go in discovering everything there is to know about the pollutants that harm our health and that of planet Earth — and why not, a few myths to debunk along the way. To guide us on this journey, Guido Lanzani, director of the air quality operational unit at Arpa Lombardia, has come forward. He has opened our eyes to some important things, starting with the precise definition of air pollution, which can be broken down "into a vast range of harmful substances present in the air, each with the potential to cause serious damage to human health and the environment."
One of the most widely discussed pollutants, for example, is particulate matter, often referred to by abbreviations such as PM10 or PM2.5. These particles of sulphate, nitrate, carbon and mineral dust — so small as to be invisible to the naked eye — are made up of a variety of solid and liquid substances, and differ from one another not in composition but solely in their diameter, and consequently in their degree of harmfulness. "Fine particles, such as PM10 and PM2.5, can penetrate deep into our lungs and even into our bloodstream, causing a range of respiratory and cardiovascular problems," Lanzani adds. The difference being that PM2.5, smaller than PM10, can penetrate more easily and therefore cause greater damage. Particulate matter can be primary in type, if released directly into the atmosphere by the source, or secondary in type, when it forms subsequently, following chemical-physical transformations of other substances — through combustion, for example. Among the other most dangerous pollutants are:
Yes indeed, our beloved pizzerias, in cities, are the main polluting sources: "In cities, the contribution of wood combustion is certainly declining — perhaps the contribution of pizzerias remains, and then that of stoves and fireplaces, which is certainly less significant," Lanzani explains. The fact remains that, according to Arpa Lombardia, today in a city like Milan traffic accounts for 36 per cent of air pollution and wood combustion for 29 per cent, of which 22 per cent is attributable precisely to the production of our favourite food.
But no, this is definitely not the only surprise that director Lanzani has in store for us. Contrary to common belief, for example, it is not true that things were better in the past. "Air pollution is a historical problem, documented since ancient times." Seneca wrote about how heavy Rome's air was due to the use of coal in the city, "and Queen Eleanor, for the same reason, "left Nottingham with her entire Court to return to her castle." All the way to London in 1952, where sulphur dioxide levels had reached 1,500 micrograms per cubic metre, compared to 5–10 micrograms today. But "even if we look at recent decades, the pollutants we were measuring in the 1970s or at the beginning of the 2000s were certainly far greater than those we have today. That doesn't mean we shouldn't continue to improve, but we certainly need to acknowledge, first of all, that a great deal of progress has been made, and that it is possible to continue reducing pollutant concentrations."
Furthermore, in Italy, a large part of traffic pollution does not come only from car exhaust pipes, but above all from brake wear, tyre wear and road surface abrasion. While the contribution of traffic to the formation of particulate matter is growing on one side, it is also true that, thanks to new technologies, filters and somewhat less polluting engines, the situation is no longer what it was a few decades ago. As a result, brake, tyre and road surface wear is beginning to weigh proportionally more and more. And so, director Lanzani explains, "in addition to introducing better technologies and less polluting vehicles, we must also genuinely pursue a reduction in the kilometres travelled."
Finally, there is the distinctly Italian case of the Po Valley, considered one of the most polluted areas in the whole of Europe alongside certain areas of Poland: not because of the volume of emissions per se, however, but because of its geographical shape. "The Po Valley is particularly disadvantaged due to the meteorological conditions that favour the stagnation of pollutants," explains Lanzani. "The presence of the Alps and the Apennines forming a frame means that pollutants tend to stagnate, leading to the formation of secondary particulate matter and ozone and encouraging thermal inversions" — that phenomenon visible to the naked eye whereby smog particles concentrate at low levels, leaving the sky clear only at higher altitudes. And the lack of rain, which when it does fall sweeps away particulate matter, has not been helping of late.
To tackle air pollution, as mentioned, it is necessary to adopt concrete measures, which have in part already had an effect where put into practice. However, meeting international standards — such as the ambitious ones set by the World Health Organization on concentrations of PM2.5 and PM10 — is no easy task. For PM2.5, for example, the current limit under Italian and European regulations is an annual average of 25 micrograms per cubic metre, whereas the WHO sets a guideline value of 5 micrograms per cubic metre.
All of this is often accompanied by very large differences between indoor and outdoor spaces, as revealed by research carried out by Dyson, which found that in 2022, across the world, two in three countries recorded higher annual average indoor PM2.5 levels than outdoor ones: in Italy in particular, the annual average levels of PM2.5 in indoor environments exceeded outdoor levels by 10 per cent.
According to the same research, Italy is among the top 10 countries (eighth place) for annual average PM2.5 level, alongside India, China, Turkey, the United Arab
