Air pollution leads to increased heart disease and lung disease incidence around the world. The influence of fine particles, that is, PM2.5, on heart and lung disorders is even greater than we thought previously. How does air pollution contribute to coronary artery disease, heart failure, hypertension, and cardiac arrhythmias?

I'm glad that you wanted to emphasize particularly cardiovascular disease, because it is rather understandable and plausible that air pollution, particularly the fine particles or the gases, affect the pulmonary system because we all breathe away several times during the day. It is a little more difficult to understand why air pollution is a big cause of cardiovascular disease. Air pollution is probably more important for heart disease than for respiratory disease. And I'll try to explain that because that is part of the more recent knowledge and my experience. Particularly the particles, in particular the fine particles. Those particles have a diameter of 2.5 micrometers (PM2.5) and less than 0.1 micrometers. They do not penetrate only into the respiratory system in the lungs, but they also get into the blood circulation.

From the lungs, fine particles are absorbed into the blood circulation. And their PM2.5 particles behave by activating blood coagulation. They activate blood coagulation and create a state of hypercoagulability. PM2.5 particles activate platelets. This is how there is an increased risk of atherothrombotic cardiovascular disease, like coronary artery disease, and cerebral artery disease, and stroke. PM2.5 particles also cause inflammation. They cause inflammation, which is a cause of atherothrombosis. It is thrombosis due to hypercoagulability and atherosclerosis. It is due to the formation and elevated state of the inflammatory system. PM2.5 particles create a mild but ongoing inflammatory system activation. This goes with the formation of atherosclerotic plaques together with hypercoagulavbility. It is the formation of thrombi in the arterial system. That's why, very briefly, PM2.5 particles cause cardiovascular disease. They also cause hypertension through the same mechanism. PM2.5 particles also alter the mechanism of blood vessel dilation of the arteries. That's how PM2.5 particles cause vasoconstriction. So these are the causes of hypertension.

And, in general, PM2.5 particles cause many other diseases, like cancer. PM2.5 particles make a low-grade inflammatory system state. That is how PM2.5 particles cause more tumors. Very recently, there was evidence that PM2.5 particles cause premature deliveries. It is a very recent study. They have shown a very high risk of premature delivery in women exposed to air pollution. So air pollution causes directly and indirectly nearly 10 million deaths, avoidable deaths, every year. If you consider that the planet has every yea 60 million deaths, 10 million represents an existential fraction. Air pollution in the rankings of the risk factors for death comes after hypertension. But air pollution [including PM2.5 particles] can cause hypertension.

Inadequate diet, smoking contributes to deaths. But again, you consider that smoking is something you can avoid because it depends on individual decisions. At the same time, you cannot avoid breathing. And so that's why air pollution is not the first risk factor of mortality and disability in the world. But air pollution is the risk that is more pervasive. Air pollution [PM2.5 particles] is what the epidemiology calls 'the highest population-attributable fraction' because smoking may be a stronger risk factor at the individual level. But on the level of the population, smoking is not so pervasive. You have to consider that fact about Europe, which also applies to other continents. Only 10% of the urban areas in Europe meet the recommended limits of air pollution that is not dangerous for health. They established the lower limit of air pollution that is dangerous for health. So, everything that is above this limit is dangerous for health. And part of the matter is that very recently - and this is a new factor of a few weeks ago - World Health Organization has further decreased this limit. The limits of air pollution are considered not particularly dangerous. But they are not reached in most urban areas in Europe and other high-income countries. Now the limits of air pollution have been further decreased. Why? Because they saw that this air pollution limit is difficult to reach and maintain. These limits were insufficient.

So, the purpose is to indicate the lower limits of acceptable air pollution that are not dangerous for health. Probably 'no danger for health' limit is zero. But be aware that they cannot reach zero air pollution; World Health Organization suggested halving the limits from 10 particles per million for PM2.5 particles to 5 particles per million for PM2.5 particles. Europe at the moment has to ratify the lower limit. So again, let us say that America is better off in that respect because recently, they are closer to the last limits of WHO limits of 10 particles per million. But it is still very inadequate, according to WHO, because now air pollution limits go to five PM2.5 particles per million. This applies to PM2.5 particles, but, of course, it also applies to gases like nitrogen dioxide.

Again you probably wonder what can be done, considering this gloomy situation? What can be done [to improve air quality]? Not much, because, of course, the very simple answer is to decrease the pollutant. And we have to consider that the main sources of air pollution depend on the countries. But they are certainly influenced by car traffic, but it's not the only source of air pollution. For instance, it is also the heating of the houses and other places where you work. There is also the dust coming from the desert. Of course, there is, as I mentioned, ammonia which is a byproduct of animal growth and also from the growing of vegetables. So he's not very easy.

What can be done? I think that the problem goes together with the problem of climate change because of the two things. Of course, the culprit is, on the one hand, the PM2.5 particles, and on the other hand, it is CO2. But it all depends on the use of products containing carbon. And so, I think that, as I say, electric cars, a better system of heating the houses, and decreasing the traffic. This is what enables us to avoid the use of fossil carbon. Fossil carbon is still widely used, as you know, by China, also by India, and also in Europe by Poland.

So what can be done about air pollution? Certainly, it is a big problem. And so people say okay, but you tell us very dramatic things, you give us some words. But what can be done? What can we do at an individual level, considering that we cannot control what is done by the people in our governments? And there I can give some advice. But, of course, I cannot completely solve the problem of air pollution because the air pollution problem is above the individual level. It is a problem of the country and the whole globe, of the whole world. Listen, we live in a city that is highly polluted because it is located on a plain landscape, with very little wind. And we are not the only ones. There are examples, I am sure, in your country, for example. In Poland, in the region of Krakow. There are other examples in Europe of cities that have little wind and bear relatively little rain, except recently, and a lot of traffic and also cold temperature.

And the only thing that we can do to avoid air pollution is taking some measures. One action is this. It is not the surgical mask but the FFP2 mask. Because they filter at least the particles. The surgical mask does very little, but they are better than nothing. So I think that we'll continue to use this mask when the problem of the pandemic is over. We will use FFP2, particularly when we go around in the streets. Of course, there are also better filters, but they are impossible to wear. They are impossible to wear in ordinary life. But these are useful FFP2 masks that became known to all of us during the pandemic.

Then other advice that I can give us is, for instance, when you walk in the city, avoid the one-way streets. Because obviously, there will be more traffic than on the two-way streets. Avoid the car parking in front of the office. How will I be able to obtain that? Because when cars start engines, they release a lot of powder. Avoid running in areas when there is a lot of traffic. There may be a nearby park, where by definition, the pollution will be less. Improve the heating of the offices or the houses because that's an important part of pollution. And I'll give you an example. During the epidemic, in China, of course, the lockdown was much more strict than it has been in our countries. Equally, there was, indeed, a strong decrease of pollutants. But mainly there was a decrease in nitric oxide, which is mainly due to car traffic.

In Wuhan, where the pandemic started, which is more in the center-south of China, this ratio was different from Beijing. Because in Beijing, the north of the country, the lockdown was much less effective. Why? Because the northern city needs for heating of the offices and the domestic houses. So during the lockdown, no traffic was much less effective in reducing air pollution in Beijing than in Wuhan because of the heat. So we attribute a lot of responsibility for air pollution to car traffic. But, of course, also to heating. And the other thing that I mentioned. So I may call another example of the difference between Wuhan and also the southern cities of China, and Beijing that is in the north, and it is cold. So for instance, it's clear that here in Milan, we have differences compared with Rome, because they are located more south. Even during the winter, in Rome, they have some heating that is not as strong as here. So I can understand what is happening in St. Petersburg or what is happening in Moscow. So I think it is not an easy problem to solve. And I think the only solution is next-generation - you. Young people in this country also make a strong effort to tackle the climate crisis. Because in this way, they will also tackle the problem of pollution that has been decreasing in the UK compared with 20 years ago. Back to the point that I mentioned to you, the very recent decision of the World Health Organization to decrease air pollution limits further. There are limits that are not being met at all by the majority of the European cities. So again, they chose to decrease the limits because they were inadequate. And they are not better at all. I told you that only 10% of the European cities meet those air pollution limits. The majority, 90% of cities in Europe, did not meet the limits. So that is what I think is the most typical example. Or also, you can not tackle pollution by medications. It is not worth it to take an aspirin. You may believe that even though it is an inflammatory process, you cannot take aspirin for this low-grade inflammation. Even though this is a mechanism whereby pollution creates cardiovascular problems, use small suggestions that I gave: use a mask. Avoid, when you walk, as I do when I come here, one-way streets. Avoid streets with a lot of car traffic. Avoid as much as possible using the car. I come here on walking but it is two kilometers so it can be easily done. So, that's the only suggestion that I can give. No drug is useful. This system is useful, and I hope the pandemic helped us learn that the FFP2 masks should be worn even going around in the streets when we go to work.

This is very important practical steps, because not everybody can escape the pollution and live in a very windy place without traffic. So I think that's very clear.

I emphasized that very clearly, because, again, air pollution is a so-called population-attributable fraction. The risk factor might be lower than that of smoking, but you can avoid smoking, or you cannot avoid breathing.