San Diego State University researchers have analyzed the impact of irrigation on farmworkers' heat exposure depending on the season and time of day.
Published in the journal Communications Earth & Environment, the research was conducted on crop fields in the Imperial Valley, where the relation between heat stress and irrigation is more likely to be exacerbated. The researchers used the occupational international standard wet bulb globe temperature (WBGT) to quantify change in temperature. WBGT is an indicator of heat exposure in humans.
The study found that WBGT can be reduced to 2.3 degrees on summer days “due to strong evaporative cooling.” On the other hand, on summer nights WBGT could go back up the same amount. Researchers also discovered irrigation increases WBGT in surrounding urban, fallow land and desert.
The study comes as employers must now comply with SB 1105, which guarantees farmworkers paid sick leave during extreme weather events.
This article was corrected to reflect an accurate change in Fahrenheit.
