2.5. Exposure risk assessment
In this paper, US EPA risk assessment guidance [21–23] was adopted to conduct the health risk assessment for workers on site who might be exposed to the Hg in fly ash. According to the site specific condition, the formulas were modified. The details are listed as below. The risks for workers exposed via the inhalation of Hg vapor and particulates emitted from fly ash can be estimated with the following equations: