part_id
- Participant Id

occasion
- 1=First visit; 2=Second visit; 3=Third visit

date
- Date of sampling

age
- Age of the participant

sex
- 1=male, 0=female

wind_speed
- wind speed (km/h)

wind_direct
- wind direction

wind_direction_degrees
- wind direction (degrees)

atm_press
- Atmospheric pressure

ozone
-  ozone (ppb)

no2
- no2 (ppb)
so2
- so2 (ppb)

ufp_mean
- Ultra Fine Particles (number/cm3)

bc_mean
- black carbon (ng/m3)

temp_bike
- temperature (degrees celsius)

rh_bike
- relative humidity (%)

pm25
- Particular Matter 2.5 (ug/m3)

Route
- cycling location: Low traffic, High traffic, indoors