Without proper ventilation, carbon monoxide can be lethal at concentrations of 1000 ppm (0.1%). However, at several hundred ppm, carbon monoxide exposure induces headaches, fatigue, nausea, and vomiting. Carbon monoxide binds with hemoglobin in the blood, forming carboxyhemoglobin, reducing the blood's ability to transport oxygen. The primary health concerns associated with carbon monoxide exposure are its cardiovascular and neurobehavioral effects. Carbon monoxide can cause atherosclerosis (the hardening of arteries) and can also trigger heart attacks. Neurologically, carbon monoxide exposure reduces hand to eye coordination, vigilance, and continuous performance. It can also affect time discrimination.
Some Service Professionals are employees, franchisees, dealers, or independent contractors ("Corporate SP's") of larger national or corporate accounts ("Corporate Accounts"). In such event, you may be matched with the Corporate Account entity or with one of their Corporate SP's. The above screening criteria is not applicable to Corporate Accounts, and therefore, HomeAdvisor does not screen the Corporate Accounts or Corporate SP's.