Tough spring for allergies? Meet a man who's been doing pollen counts since 1968

Almost every day, Jim Anderson climbs the stairs to the roof of the six-storey building where he works in London's SoHo neighbourhood. And while it offers an eye-catching vista of London's skyline, he's not up there for the view.

He makes this daily ascent to tend to an instrument called a volumetric spore trap. 

Anderson, who is a aerobiologist, retrieves from the trap a slide covered with a thin layer of sticky grease, not unlike a fly trap. The instrument sucks in air at the rate of two litres a minute, blowing it against a four-inch wide strip of film that moves slowly past this air stream at the rate of a few millimetres an hour. 

But instead of flies, the slides in the counter are designed to trap samples of spores for study and analysis. It can also gather samples of pollen, which is what Anderson uses it for. 

"Handy dandy that you can do both in one instrument," he said. 

Anderson then takes the sample by to his office, stains it with colouring, puts it under a microscope and scans over the slide, counting the number of various types of pollen he sees. In the spring, he tends to find plenty of tree pollen. In summer, a lot of grass pollen is captured. As summer turns to fall, he finds more ragweed. 

Once his count is complete, Anderson enters the raw data into a spreadsheet and submits it to American Academy of Allergy, Asthma and Immunology in Milwaukee, WI. 

Each pollen type has a specific shape which Anderson has learned to identify and count. He posts the London data daily at on this Facebook page. 

Anderson has been doing this painstaking work it since 1968.

Why? 

"I just like doing it," he said. "I just got hooked." 

The data gathered by Anderson, and by other volunteers like him at stations across North America, is made available to scientists for study. He isn't the only one doing pollen counts. The Weather Network uses data gathered at sites across the country, including London, for its allergy outlook. 

Data on the level and type of pollen in the air is crucial for allergy sufferers who suffer from symptoms that range from itchy eyes to constant season when exposed to certain pollens. 

Data Anderson gathered this spring found that this April had the highest total tree pollen count since 2010, more than three times higher than last years.