December 5, 2021

I, Science

The science magazine of Imperial College

From hammerstones to biotechnology: Lizzie Norris looks at the engineering that has helped us to increase our lifespan and improve our quality of life.

960px-KundaCultureTools-WikimediaThe last 2.6 million years have seen the breadth of human engineering and invention. From ancient humans using hammerstones to hunt animals to modern day biotechnology and complex drug delivery systems, we have used engineering to change ourselves and the world around us.

Engineering is fuelled by an immediate need to solve problems and improve our environment. Many of the greatest lifesaving engineering developments are simple and low tech. Take the seat belt for example or the LifeStraw, a recent award winning innovation which is used to purify water for those living in developing countries.

However good engineering is not easy; many of the simple inventions in use today are examples of bad engineering. Luer (Tubing and Catheter) misconnections are examples of this. Misconnections allow gasses and liquids to enter the wrong lines in patients, while bad catheter insertion can also cause problems with pressure build up when inside the body causing tearing and tissue damage.

life straw TU Delft 4940647003_ef305d98b8_bWhat is good engineering and how have we used it to improve ourselves? The last few hundred years have seen many innovations which have increased our lifespan. It is difficult to pinpoint specific solutions that have done this but vaccinations and the invention of antibiotics are a good place to start. The smallpox vaccine is credited with saving the lives of approximately 530 million people worldwide, whilst the measles vaccine has saved an estimated 118 million lives. The development and large-scale deployment of antibiotic drugs has saved around 82 million lives.

Access to clean water and sanitation have also had a considerable impact on our way of life. How many lives has the invention of the sewer system saved? What about the role of soap in preventing the spread of germs? Could soap be credited as being one of the most fundamentally important inventions? We could speculate forever.

Northern Sewage Project, site photography works 21.04.10
No, not part of the LHC, but a sewer!

Life expectancy statistics are useful when considering these questions. However they are often skewed by factors such as high infant mortality rate and may not represent the age most adults lived to. Statistics from the 1700s show that while the average life expectancy at birth was 25-40 years, if you survived childhood, your life expectancy might increase significantly beyond the ‘at birth’ expectancy. So how have we reduced infant mortality rates?

Low birth weight (LBW) is a primary cause of infant mortality. In developing countries this accounts for 60-80% of infant deaths. The rate is increased by the young age of mothers, poor nutrition, air pollution, and drug and alcohol abuse.

The World Health Organisation estimates that indoor air pollution causes more than 1.6 million premature deaths yearly, the majority of these in children under five. More than half of the world’s population use open fires or traditional biomass stoves to cook. Household members, particularly women and children, are exposed to smoke and, by extension, to high risk of death or illness from respiratory problems.

So how have people attempted to counter this problem? While the Romans used tubes inside the walls of bakeries to draw smoke out, chimneys only appeared in dwellings in Northern Europe in the 12th century. They were engineered as a solution to reduce the build-up of smoke in the home, but the long-term health problems associated with smoke inhalation have only recently become well understood.

Despite this knowledge, in many communities today fuel supplies are limited, so anything from kindling to dung is burned for cooking and heating. The architecture of many dwellings often makes chimneys or fume extraction impossible. There are many organisations working to produce cleaner stoves and to encourage the use of cleaner fuels.

Haber-Bosch-En_1024wUnder-nourishment and starvation also significantly contribute to LBW and premature death. History is littered with periods of famine all over the world. However, history also yields examples of innovative solutions to some of the key drivers of famine. For instance, rapid population increase in the 1800s meant that farmers struggled to produce enough nitrogen from manure to fertilise farmland. Scientists were unable to synthesise nitrogen until the early 1900s, when Haber and Bosch produced an industrially viable solution. In his book, ‘Enriching the Earth’ University of Manitoba Professor Vaclav Smil calculated that over 2 billion people, just under 40% of those alive at the turn of last century, were fed by food grown using the Haber-Bosch process, demonstrating that discovery and invention continue to form the very basis of the way we live our lives today.

Identifying the inventions of today that will have the biggest impact on our lives is difficult, as lone feats of engineering rarely improve the lives of many. It is the cumulative effect of many different minds, components and refinements over time that produce strong solutions which lead to a significant impact on our lives.

Lizzie Norris is studying for a PhD in Advanced Characterisation of Materials

Images: Kunda culture tools (Wikimedia); Life straw by TU Delft (Flickr); Northern Sewerage Project tunnel by Melbourne Water (Flickr); Haber-Bosch process (Wikimedia)