The Causes of Asthma Content from the guide to life, the universe and everything

The Causes of Asthma

4 Conversations

Asthma is a condition in which the small airways of the lungs become inflamed, causing difficulty in breathing*. The usual symptoms are coughing, wheezing, getting short of breath or a tight feeling in the chest. Around one in 25 adults and one in seven children* in the UK have asthma.

Facts and Figures

Whilst the number of people diagnosed with asthma is rising1, the number of people dying of it is falling. Deaths peaked at just over 2,000 in 1988 and have fallen to around 1,500 per year in England and Wales. The majority of asthma deaths occur in those aged over 45, with around 40% occurring in the 75+ age group. Only a very small proportion (1%) occur in children*.

Causes of Asthma

  • Asthma attacks can be triggered by viruses, pollens, mould and fungus spores and other indoor and outdoor air pollutants.

  • It is a common but mistaken belief that air pollution from traffic is the biggest cause of asthma. Outdoor air pollution was much worse in British cities in the early part of the century, and if that were the direct cause, then the UK would have experienced a sharp fall in asthma sufferers since then, and there would be a clear difference between city and country-dwellers. In actual fact, children across the UK have fairly similar levels of asthma. Most people in Britain spend over three-quarters of their time indoors, so exposure to indoor air pollutants is probably more significant.

  • Indoor air pollutants include house dust mites and their droppings, pet dander (bits of skin), feather-bedding*, tobacco smoke, bird droppings, mould spores, tobacco smoke, and nitrogen dioxide and sulphur dioxide emissions from gas cookers and appliances. House dust mites thrive in a warm, moist environment and live in carpets and soft furnishings, so modern centrally-heated, double glazed homes are just the right for them. It is much easier for people to blame fumes from cars and lorries for the increase in asthma, than it is to blame the dog and the fitted carpet and the double glazing that you just paid thousand of pounds for.

1There is an increase in awareness of the condition, so that doctors are now more likely to correctly diagnose it than in the past. Despite this, asthma prevalence is rising, even taking into account greater awareness of the condition.

Bookmark on your Personal Space

Edited Entry


Infinite Improbability Drive

Infinite Improbability Drive

Read a random Edited Entry

Categorised In:


h2g2 Entries

Write an Entry

"The Hitchhiker's Guide to the Galaxy is a wholly remarkable book. It has been compiled and recompiled many times and under many different editorships. It contains contributions from countless numbers of travellers and researchers."

Write an entry
Read more