Table 1:

The list of collected features

Feature Domain	Options
Exhaled CO (ppm)	1. < 10; 2. [10, 20]; 3. [20, 30]; 4. > 30
# Years Smoked	1. < 10; 2. [10, 20]; 3. > 20
Age	1. < 25; 2. [20, 25]; 3. > 50
Sex	1. Male; 2. Female
Race	1. White; 2. American India; 3. Asian; 4. Black; 5. Hispanic; 6. Other
Ethnicity	1. Non-Hispanic; 2. Hispanic; 3. Unknown
Education	1. Elementary; 2. Middle; 3. High; 4. Coll/Tech; 5. College Graduate
Marital Status	1. Single; 2. Separated; 3. Widowed; 4. Married; 5. Divorced
GPS Measurements	Longitude; Latitude; Speed (km/h); Distance (m)
Time of Day	1. Night; 2. Morning; 3. Afternoon; 4. Evening