How Ventilation Impacts Asthma Sufferers
Today's working aged adults are known as the ‘Indoor Generation’. This is because they spend almost 90% of their time indoors, which means the average person gets just 144 minutes or so of fresh air each day.
With so much time spent indoors, the role ventilation plays is significant. Especially for the 262 million people with asthma. In this article we explore the role of ventilation in respiratory health and how asthma sufferers can benefit from making sure they live in well-ventilated spaces.
Asthma Is On The Rise
Asthma is a chronic lung disease caused by inflammation and muscle tightening around the airways. This restricts the sufferers ability to breathe and can result in coughing, wheezing, shortness of breath and chest tightness. These symptoms can be mild, moderate or severe. At their worst, they can be fatal and in 2019 there were 455,000 recorded deaths attributed to asthma.
The exact cause of Asthma remains stubbornly elusive. We know it’s more likely to occur in individuals who have a close relative with the condition. We also know there is a close relationship between asthma and allergic conditions such as eczema and rhinitis (hay fever). It’s also widely accepted that the risk of asthma is likely to increase if exposed at an early age to environmental allergens and irritants, such as house dust mites and moulds.
Urbanisation is also thought to be a contributing factor to asthma and one of the reasons for the steady incline in asthma sufferer numbers over the last three decades. According to the National Institute of Health in the United States, this is particularly true amongst children and teenagers who live in urban areas in medium or low-income countries.
However, despite New Zealand not being overlay urbanised by world standards, and despite being considered a high income country, the prevalence of asthma in New Zealand is high. One in eight New Zealanders take medication for Asthma and 100,000 kiwis were admitted to hospital for asthma attacks in 2019.
The highest number of these hospital admissions are for asthma sufferers from Maori and Pacific people, residing in deprived areas. In fact, Maori are 3 x more likely to be hospitalised from Asthma than Europeans or other New Zealanders. The collective cost of hospitalizations and treatment for asthma sufferers comes in at $1 billion per year.
Whilst we don’t know of any studies which would support our hypothesis, we think it would be reasonable to suggest there is a correlation between the poorly ventilated housing more commonly inhabited by Maori, and the increased prevalence of Asthma in Maori.
How Building Standards Can Impact Asthma
Asthma can be triggered by exposure to indoor allergens such as dust mites, moulds, rodents and pet dander (skin cells shed by domestic animals such as cats and dogs). Then there’s other known allergen triggers, such as tobacco smoke, volatile organic compounds and fungi.
Asthma triggers are more prevalent in substandard housing characterised by higher rates of allergens, with increased rates of moisture or dampness, and poor ventilation. We know New Zealand has a damp home problem so it should come as no surprise we have an asthma problem too.
This is not to say asthma, with all its triggers, is reserved just for families residing in older, damper homes. Modern homes are remarkably airtight and this can lead to unintended consequences, with the moisture created inside (hot water, cooking etc) having nowhere to go. Then there’s all those furry animals and the aforementioned pet dander.
The Role of Ventilation in Preventing Asthma
Proper ventilation solutions will maintain the optimum number of air exchanges per hour. Bringing in fresh air and allowing contaminated air to escape, ventilation regulates the overall internal air quality and will reduce humidity levels. In turn, this inhibits mould growth and minimises the conditions asthma triggers are known to thrive in.
Ventilation will also help reduce airborne pollutants, microbial contaminants and volatile organic compounds (VOCs). These are chemicals that can vaporise into air and are commonly found in a multitude of household cleaning products, paints, varnishes, degreasing products, and even cosmetic products.
Basically, the air in the internal environment can be dangerous if it’s not ‘cleaned’ with fresh air, and whilst the threats posed are undeniably worse in substandard housing, they exist in every environment because even when the building itself does not contribute to issues, occupants introduce danger in the form of pets and VOCs. It sounds a little dramatic, but for the asthma sufferer that’s exactly what it is.
The effective remediation of existing housing stock can help reduce the risk. Trials in New Zealand have shown how adding insulation (when it was previously lacking) will help decrease moisture and mould exposure when paired with ventilation solutions, and after mould eradication the occupants reported reduced asthma symptoms and medication use.
For new housing stock, a multi-trigger, multi-component approach is more effective. In this approach, asthma friendly housing is created by adopting multiple changes. Ventilation is the cornerstone of the approach and there’s a requirement for fresh air, sometimes filtered through HEPA filters (for mechanised ventilation), along with spot ventilation in all kitchen and bathroom areas (noting this goes beyond the magical 5% number often considered acceptable in New Zealand).
The approach goes further, advocating for the use of low VOC paints, low pile stair carpeting, HEPA filtered vacuum cleaners and low VOC fixtures and fittings. There is even a recommendation for all carpeting (aside the low pile star carpeting) to be removed and hard floor surfaces only.
Ultimately, how far the home design can go is up to the owners and designers. What is certain is that any approach for creating asthma friendly homes involves proper ventilation, and when proper ventilation is evident, there will be some relief for asthma sufferers. This much is evident from a study in the American Journal of Respiratory and Critical Care Medicine, which found that improved ventilation in homes decreased asthma systems and improved lung function in children. It may even prevent younger children from developing asthma.
The simple truth is fresh air let's asthma sufferers breathe more easily. And proper ventilation makes sure the air inside, where we spend almost all of our time, remains fresh.