There is a possibility that very early inflammatory effects among these workers could be succeeded by adaptation and thereby reduction of effects. In this case, the inflammatory response at some time after employment could be smaller than observed initially. This may lead to underestimation of effects. The investigators consider that a dynamic cohort design including only subjects exposed for the first time in this industry is not feasible. However, a follow-up of three years is considered sufficient to detect clinically relevant changes. The cohort in this study will also have a relatively short prior employment in the industry because the plants were opened in 2006 and 2009. Spirometry screening of all workers, performed during the first days of employment at the local health services, is available. These will be compared with the baseline recordings to evaluate possible effects prior to inclusion in the present study.