By Dr. Colin Michie FRCPCH University of Central Lancashire.
We spend a great deal of our time indoors, but the air inside is often less healthy than the air outside. There are greater risks to our health from pollution inside our homes. For instance, fungi and their spores are likely to share our living spaces.
Fungi include moulds and mildews: they grow well with moisture and warmth. They are everywhere, as normal inhabitants of our environments. Their tiny spores are found in the dusts around us; many are smaller than a red cell and are not visible to the naked eye. “Normal” homes are likely to have 3-6000 spores per cubic metre of air – we commonly breathe in 1000 spores an hour. After flooding in New Orleans homes, spore counts a hundred times greater were found.
The networks of tiny tubes through which we breathe are designed to remove dusts. Cells there make mucus that is moved by short hairs that line the tube surfaces. These cilia move continuously in coordinated waves, whether we are awake or asleep, lying or standing, to move the thin mucus blanket upwards towards the mouth – we usually swallow this material. The mucociliary clearance system is crucial to airway defences and health, because the mucus carpet traps all types of particles. It may protect us from invisible particles of silica from the Sahara, viruses from our nearest human contact or mould spores from that patch in the kitchen.
Of all the living particles in dusts, we could be concerned about viruses, bacteria and fungal spores that might infect us. Breathing in these critters is the first step towards being infected by them. Lung surveillance systems run by the immune system check the mucus to remove and kill potential invaders. Damage to immune protections can compromise our safety, just as strengthening them with appropriate physical activity, nutrition and vaccinations will reduce risks.
The link between a damp home and respiratory health is strong, particularly for small children, older adults and those with underlying illnesses. Some recent studies have associated mould exposure with anxiety. Mould spores can be an irritant to anyone. They cause allergic reactions and often make asthma worse. Although a mould patch in the kitchen or bathroom cannot be linked with a specific illness, a reasonable approach is to minimise fungal colonisation of our living spaces.
Several species of mould grow on our damp walls, wet ceilings, grouts and humidifiers. Black mould (typically Stachybotrys chartarum) attracts headlines, but others such as Cladosporium can cause allergic attacks, while Aspergillus can infect lung tissues and make highly toxic aflatoxins. These toxins can potentially damage immune defences. Reducing fungal numbers requires cleaning, then removing any sources of moisture. Condensation without appropriate air exchange, or water leaks are common culprits. Maintaining a clear living space requires low humidity and adequate ventilation – this may mean improving air flow, drying clothes outdoors or using extractor fans. These manoeuvres are particularly challenging on a tropical island with frequent rain. In clinical situations, the use of ultraviolet light or ozone, sometimes delivered by robotic systems, effectively removes fungal organisms from surfaces and water supplies.
Asthma is a common, long-term lung condition causing difficulty in breathing. It is particularly frequent in school-age children. Air becomes trapped by inflammation in a patient’s narrow lung tubes. Asthma may be severe and potentially fatal. It can compromise pregnancy; it may have an impact on schooling in the young. Its inflammatory changes cause more mucus to be produced and the small muscles around the airways swell too. Asthma is commonly linked to inflammation of the nasal passages and sinusitis.
Asthmatic attacks are usually triggered by specific situations – for some, a mild throat infection; for others, cold air, dusts, house dust mites. Allergic reactions to a food, a bee sting or anxiety can all exacerbate asthma. Sufferers will typically experience wheezing, a sensation of a tightness in the chest, together with coughing at night, early in the morning or with exercise.
Asthma can be managed using medications directed to open airway muscles, along with anti-inflammatory treatments. Some treatments involve the use of inhaled dusts – particles of therapeutic medication can target those fine tubules in the chest. Asthmatics may monitor their airways by blowing into a flow meter.
All those with asthma will observe that removing their environmental triggers is a critical part of reducing their attacks. So, for children, it is worth considering whether moulds are linked to their coughing: Are their school rooms clear of mould too? Skin prick tests or blood tests can be used to find out if someone is sensitive to a mould, but such investigations should not take the place of removing the fungi!
Mould is just one of many allergens that may impact asthma. Reducing the fungal burdens in our homes and schools will improve indoor air quality and health, for all.
Useful resources:
https://www.nhs.uk/conditions/asthma/
Dr. Colin Michie is currently the Associate Dean for Research and Knowledge Exchange at the School of Medicine in the University of Central Lancashire. He specializes in paediatrics, nutrition, and immunology. Michie has worked in the UK, southern Africa and Gaza as a paediatrician and educator and was the associate Academic Dean for the American University of the Caribbean Medical School in Sint Maarten a few years ago.
