Mean CO levels at the beginning of the workday are not significantly different. By mid-morning coffee break, however, passive smokers experience twice the level of CO exposure compared with nonsmokers. The CO level falls shortly after 12:00 noon when many leave the work area, then peaks immediately after lunch hour and remains high into the evening hours. Where smoking is permitted, ventilation is not sufficient to sustain CO concentrations below 9 ppm, which Holbrook defines as the “upper limits’ of CO for enclosed areas with adequate ventilation. flovent inhaler
Prior research has shown that light smokers (smokers of one to ten cigarettes per day) experience 1.7 times more wheezing, 1.5 times greater sputum production and 3.9 times more cough than nonsmokers. In our study, 70 percent of the passive smokers complain of chronic coughing, occurring about three times more often than in nonsmokers. Almost 70 percent of passive smokers experience chronic phlegm symptoms and they produce phlegm nearly 3l/2 times more often than nonsmokers. Passive smokers also complain of shortness of breath 4Vz times more often than nonsmokers. These results agree with other studies that looked at the symptomatic responses of headache, nasal irritation and cough to chronic passive cigarette smoke exposure in healthy subjects.