As used in this chapter:

(1) “Environmental health” means the study, art and technique of applying scientific knowledge for the improvement of the environment of man for his health and welfare;

(2) “Sanitarian” means a person trained in environmental health who is qualified to carry out educational and investigational duties in the fields of environmental health such as investigation of air, water, sewage, foodstuffs, housing and refuse by observing, sampling, testing and reporting and who is licensed pursuant to § 20-361; and

(3) “Commissioner” means the Commissioner of Public Health.