Victorian capital is hayfever HQ – but pollen unlikely primary culprit
The Amazon rainforest seems an unlikely base for discovering why greater Melbourne is a hayfever hotbed, but pollen dispersal in Brazil points the finger at urban allergy sources here at home
READING LEVEL: GREEN
An Amazon rainforest study has shed light on why Melbourne is the hayfever* capital of the world.
When greater Melbourne’s pollen* count hits 50 grains per cubic metre, expected this year to occur in late October, the city’s hayfever season formally kicks off, even though many may be suffering symptoms already.
“We are the capital of the world for allergies, for hayfever … at least one in three people in greater Melbourne suffers from it,” La Trobe University study co-author Dr Philip Taylor said.
The Victorian capital’s notorious* “four seasons in one day” variable weather, together with introduced* grasses and vegetation, particularly birches and plane trees, sees the city suffer the highest allergic reactions anywhere.
Now, a five-year study, carried out using the 300m-high Amazon Tall Tower Observatory* in Brazil, has shed new light on pollen air travel and the causes of urban hayfever.
Tracking the height and travel distance of hayfever-causing particles like pollen and fungi* in the pristine* atmosphere above the Amazon, scientists found “giant” aerosols* such as pollen generally do not achieve the height required for long-range dispersal*.
“We found that, rather than rising high into the air and scattering over large distances, pollen actually travels fairly low to the ground,” Dr Taylor said.
“City-dwellers often blame the country for their hayfever symptoms, even as farmland grows more distant, but biophysics tells us that the cause must be much closer to home.”
Rye grasses in suburban lawns, nature-strips and sports fields, together with European trees and fungi are the main contributors to urban hayfever.
“We now know that pollen can’t travel very far, which suggests our urban streets and backyards are more likely to blame for symptoms,” Dr Taylor said.
Councils mowing reserves more frequently and greater use of native plants and trees can help reduce hayfever, but Dr Taylor said Victoria’s frequently-changing weather increased pollen dispersal.
“Melbourne’s ‘four seasons in one day’ weather instability leads to pollen being fragmented* and causing more allergic reactions,” Dr Taylor said.
The study is published in Nature – Climate and Atmospheric Science.
GLOSSARY
- hayfever: allergic immune response causing sneezing, runny nose and watery, itchy eyes
- pollen: fine powder produced by male part of flowers that fertilises other flowers of the same species and produces seeds
- notorious: well known for something bad or unfavourable
- introduced: not native to a place or region
- observatory: place given over to or equipped for observing nature and natural phenomena
- fungi: plural of fungus, a simple organism or living thing that is neither plant nor animal
- pristine: original and pure, not spoiled or sullied or contaminated in any way
- aerosols: tiny floating dust particles and droplets in the air
- dispersal: spreading across or moving away from an area
- fragmented: made up of several separate parts
EXTRA READING
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How to become your own snot detective
QUICK QUIZ
- What pollen count formally marks the start of greater Melbourne’s hayfever season?
- Which two trees contribute to the city suffering the highest allergic reactions anywhere?
- How tall is the Amazon Tall Tower Observatory?
- Scientists found that pollen does not generally achieve what?
- What are the three main contributors to urban hayfever?
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CLASSROOM ACTIVITIES
1. Create an infographic
Why is Melbourne “the hayfever capital of the world?”? Use all of the information in the story to create an infographic or explanation using pictures and/ or diagrams, that would help other kids understand the answer to this question.
Time: allow 40 minutes to complete this activity
Curriculum Links: English; Science; Health and Physical Education
2. Extension
What does it mean to have “four seasons in one day”? Can you think of a better way to describe this? Think of a new expression that sums up or describes this type of weather pattern even better.
Time: allow 15 minutes to complete this activity
Curriculum Links: English
VCOP ACTIVITY
1. Summarise the article
A summary is a brief statement of the main points of something. It does not usually include extra detail or elaborate on the main points.
Use the 5W & H model to help you find the key points of this article. Read the article carefully to locate who and what this article is about, and where, when, why and how this is happening. Once you have located this information in the article, use it to write a paragraph that summarises the article.
Time: allow 25 minutes to complete this activity
Curriculum Links: English, Science