Tobacco leaves are highly moist up until they are harvested, then depending on their type and the final use, the ERH can vary quite significantly, so measurement and control is a significant factor in processing environments and the product quality.

Application: ERH of tobacco 
ERH is a key factor in quality (Cigars especially), hence the use of humidors in the storage of the best quality products. Handrolling tobacco is usually has a high ERH value, taylor mades - medium ERH. Handheld insertion type instruments are used in bulk checks, water activity units tend to be used in the laboratory environment. 
  
Products 
Portable 
Water Activity

Application: Drying process to produce correct ERH levels

Products 
Transmitters

Application: Datalogging storage and transport conditions 
Tobacco products are often shipped long distance, transportation conditions can be a key factor in end user acceptance. 
  
Products 
Dataloggers