Yes, and for a number of different reasons:
Exposure assessments should be undertaken during the time of year when the hazard is at its worst. This will allow the controls implemented to be relevant for the typical worst case exposure so that you can keep your team safe and healthy. We have seen first-hand the difference in carbon monoxide levels from LPG forklifts in a store with the roller doors opened and closed. When the doors were closed the levels approached the Workplace Exposure Standard of 25ppm but when they were opened the levels dropped to around 5ppm. Therefore, it was clear that either electric forklifts were needed or mechanical ventilation was required to increase the amount of fresh air introduced when the roller doors were closed.