What about other forms of air pollution?
Are there factors other than diesel exhaust that contribute to someone’s hay fever?
Is it possible that regular gasoline exhaust, which is the standard in the U.S., also adds to hay fever problems?
What about smoke from tobacco, industry, or even wildfires?
To find the answers, we need to look at scientific studies...
One study found that hay fever is connected to poor air quality. This cross-sectional study, from researchers at Brigham and Women's Hospital in Boston, Massachusetts, analyzed past surveys on respiratory issues and looked at historical data for air quality, which included information for pollutants, carbon monoxide, nitrous dioxide, sulfur dioxide, and particulate matter.
Lining up the two data sets, researchers discovered that “improvements in air quality are associated with decreased prevalence of both hay fever and sinusitis.” (Sinusitis is an inflammation of sinus tissue; it essentially means blocked sinuses.)
A study from South Africa seems to support the “super pollen” theory as well as the theory that air pollution contributes to allergies.
The study analyzed the presence of truck traffic. (By “trucks, it’s fair to assume they mean diesel-engine semi trucks, although the study mentions both petrol and diesel.)
The research asked school children questions about “truck traffic” near their home, as well as the presence of allergic rhinitis. Researchers found that the "results support the hypothesis that traffic related pollution plays a role in the prevalence of allergic rhinitis symptoms in children residing in the area."