Our air is generally quite irritating, with a million allergens floating about that affect our ability to breathe pleasantly. Air irritants do not just exist wherever we are, they also travel with us wherever we go, and this can be especially dire if you have asthmatic or allergic tendencies already. According to one of SA’s leading pharmaceutical companies, specialising in allergy treatments, nasal allergies already affect close to 20 million people in the country – a figure which is set to increase as a result of airborne pollutants amongst others.

So what exactly is it that triggers an allergic reaction?

At the core of it is your immune system. It mistakes some things in your surroundings for a serious threat and attacks them, causing allergies. Research has always recognised seasonal pollen as a major trigger of these attacks, but now there appears to be an accomplice in the assault on allergy suffers. And we’re faced with it every day as we drive to and from work – diesel emissions that gush from older vehicles that do not feature the technologies to filter their emissions.

Over the last decade, manufacturers of diesel engines have made giant steps forward in reducing tailpipe emissions, but SA’s relatively old diesel car parc remains a major source of atmospheric soot, which is spurring the rise in allergies and other respiratory conditions. Wilmi Hudsonberg, spokesperson for Pharma Dynamics says while the introduction of new diesel engines, which now comes equipped with advanced filters and catalysts, are encouraging, SA’s car parc is relatively old. “The average age of a light passenger vehicle in SA is around 11 years, while most taxis and buses that typically use diesel are 14 years or older. The maturity of our car parc has a direct implication on the quality of our air and subsequently our health.

Diesel pollutants can either exacerbate the symptoms of those already prone to allergies or trigger latent allergic reactions in those who were previously not allergic, causing the body to create more antibodies and thereby increasing the allergic immune response.

“Diesel exhaust contains about 100 times more carbon particles than petrol and remain airborne for a long time. To make matters worse, when pollen particles bind to diesel particles, they go a lot deeper into the airways since diesel particles are much heavier and in turn, a chemical reaction takes place when the two combine, which make it more allergenic,” she says.

In South Africa, diesel car sales are rising and show no signs of slowing down. Since 2008 overall sales of diesel-powered vehicles have almost doubled with diesel cars making up about 22% of our country’s car parc of which about 46% (1 042 510) are older, non-emission controlled diesels.

Hudsonberg says the large number of older diesel vehicles on our roads and their continued use poses a serious health risk. She cites figures from the most recent State of SA’s Air report released by the Department of Environmental Affairs, which highlights that the three biggest types of air pollution are sulphur dioxide, particulate matter 10 and particulate matter 2.5 – the latter emanating mainly from diesel tailpipe emissions.

Hudsonberg adds that commuting can also add to allergy sufferers’ misery. “When traveling to work – whether in a bus, taxi or car, rather close the windows and turn the air conditioner on. The air-con should filter out all the diesel particles to lessen your exposure and alleviate symptoms.”