What Does Airborne Dust Do to Our Lungs?

The effect of airborne dust depends primarily on particle size: according to pulmonologist Dr. Katalin Várdi, larger dust grains cause coughing and inflammation but the body clears them out, while smaller ones settle in the lungs and, with prolonged inhalation, can start a permanent remodelling. In the interview we also asked what the indoor air and the heating matter here.

The heating method affects the movement of dust. With heating that circulates air, the rising warm air carries dust with it; radiant infrared heating warms the surfaces and the people in the room, so it stirs up settled dust less – and the same is generally true of low-temperature surface heating, for example wet underfloor heating. No heating removes dust, and none cures disease. How indoor air relates to the health of the respiratory system, we asked Dr. Katalin Várdi, who as a pulmonologist and sleep medicine specialist has for more than 35 years dealt with the whole spectrum of non-cancerous lung diseases and sleep disorders.

Katalin Várdi

How do we filter the air we breathe in?

To prevent respiratory problems, it is usually recommended to avoid smoking and polluted air. How does polluted air – indoors, airborne dust – lead to health problems?

Airborne dust contains, on the one hand, dust mites, which are allergens. Besides allergy, COPD is talked about less often, though it belongs here too. What problem the substances in the dust cause depends partly on the size of the particles that get in, and partly on where they end up.

We have many "filters". The first is the nose itself, the nasal mucosa, but the sinuses also belong here: the two maxillary sinuses, the two frontal sinuses, the two sphenoid sinuses and the region of the ethmoid cells, which clean, warm and humidify the air we breathe in. Spread out, this is roughly two palms in area, whereas the lungs "unfolded" would be the size of a tennis court. So if the filter system of the nose does not work well for some reason – because of allergy or an upper respiratory illness – dirty, unfiltered air reaches the lungs.

The question is how many microns the dust is that gets in. Larger dust grains cause coughing and inflammation straight away, but they somehow get out; smaller airborne dust, however, "settles" into the lungs, and can mean a permanent problem. That is why it matters how someone breathes: through the nose or through the mouth – mouth breathing can cause many problems.

There are various theories about what exactly makes someone allergic; in essence, cleanliness and an infection-free environment can help avoid it. Airborne dust, moreover, means not only the dust grain itself but also the tiny amount of liquid around it, which changes the viscosity of the mucous membrane and, through it, the distensibility of the airways. That is why it is worth getting rid of dust locally, for example with an evening nasal rinse, so that harmful substances do not travel further down into the lungs.

Dust particles can also be got rid of with moist steam, or in an environment where salt is present in a physiological concentration. This helps restore the natural state of the mucous membrane, so it does its cleaning work much more effectively. This is what salt rooms are for – but you have to sit in a salty environment for quite a while for it to count.

What happens if we breathe in fine dust over a long time?

In this case the lung tissue starts a so-called inflammatory cascade, as a result of which abnormal mucous membrane forms and the lung remodels badly – this is called remodelling. Instead of the original structure, a thicker bronchial mucosa develops, which produces secretion and narrows the airway: this is chronic bronchitis, practically a narrowing bronchial inflammation, which is also common in children.

Back then, on what was then Mártírok útja (in Budapest), air pollution was measured at exactly the height at which prams are pushed – and bronchitis occurred more often in children walked there. Of course many outgrew it, but nothing passes from the body without a trace.

The other process, typical for example with the industrial dust concentrations of Chinese or Indian megacities, is emphysema: the lung remodels so that it no longer heals and cannot be treated with medicines either. It seems there are more and more patients in the world who end up in this situation not because of smoking but because of polluted air. If at home, in the flat, a large amount of airborne dust is added on top of all this, these effects are further strengthened. That is why it is worth paying attention to the cleanliness of indoor air, and why "lung-friendly" heating solutions are also important.

Asthma and the air in the home

We have not talked about asthma yet. Can someone be asthmatic because of indoor air?

They can. If the nose does not filter the air enough, asthmatic cough can develop. The main difference between asthma and chronic bronchitis or emphysema is that asthma is – demonstrably, by measurements – a reversible process.

Does that mean that if the quality of the air improves, the condition can improve too?

Yes, we have long known this, which is why various forms of climate therapy are used: highland, seaside and cave. The essence of cave therapy is that the patient goes down into a cave several times for an hour or two, where the air is extremely clean, poor in dust and germs, so for example fungal particles do not enter the body either. There is a lot of experience of how much these treatments mean, and a salt room at home can also do much to improve patients' condition.

Temperature, humidity and sleep

Why does air irritate if it is dry or too warm, and why is it better if the flat is cooler and more humid?

Cooler, more humid air does not necessarily have pulmonary significance: cooler air acts on the body's circadian rhythm, and that regulates our sleep.

So there is a link between sleep quality and the air as well?

For sleep we consider cooler air of 19–21 degrees the best. It may seem strange, because not everyone likes it, but for sleep depth and our internal clock it is good: in the cool, sleep is a little deeper, and interestingly waking is also better and quicker.

Breathing therapy – and where would you try infrared heating?

You develop a personalised breathing therapy. What does that mean, and who is it recommended for?

I deal primarily with asthmatics, COPD patients, people with non-cancerous lung diseases and people with sleep disorders. With our own method we supplement the drug treatment of lung patients. We call this rehabilitation; exercise and sport are part of it, but not in general: we look at which form of movement is most recommended for the particular patient, and which can be fitted into their life. We have also included singing in the programme – in our experience, the experience of creating and the community help very many people a great deal.

Is there a hospital ward dealing with lung patients where you would see sense in trying infrared heating and gathering experience?

For example with cystic fibrosis patients – children and adults alike – it would be worth trying, either in hospital or in the patients' homes. It is a genetically determined disease that without proper treatment gets worse in any case, but it still matters whether the patient encounters infectious agents in their environment. I think it would make sense to try infrared heating in such special places.

What does this mean when choosing heating?

The doctor's last thought is a professional suggestion, not a test result: we do not attribute any healing effect to infrared heating. What the heating method can influence is the movement of dust and the temperature of surfaces; it does not replace cleaning, ventilation or, for an asthmatic or allergic family member, the advice of the treating physician. You can read about one of the main house dust allergens in our article on dust mites, and about mould in our piece on the mouldy wall. Many people regard the electric field of electric underfloor heating as a health question too – we present our own measurement on the electrosmog page.

The interview was conducted by Éva Flanek, PR and education lead of the Hungarian National Electric Heating Association