Workplace exposures to dusts and chemicals in industrialised countries continue to decrease overall (while they remain constant or are even increasing in the developing world). However about 10%–25% of asthma morbidity in adulthood is still estimated to be associated with occupational exposures.1 Exposures to high molecular weight occupational allergens such as animal antigens, flour, grain dust, and latex and their relevance to health have been extensively studied in the past2–4 and prospective cohort studies on this topic have also been published.5 6 What has not yet been prospectively studied over a long period is the association between low molecular weight allergen and irritant exposures and their association with respiratory health in young adults followed from the start of their professional life well into adulthood.7 So far general population cohort studies and studies among specific trades have indicated that these exposures also contribute to the burden of asthma and rhinitis in adulthood.1 6 8–12 However as they were mainly confined to small numbers in specific trades or only followed participants …