Figure 4: Box-whiskers plots of outdoor and indoor ozone measurements taken in 29 dwellings in Athens depicted for all daytimes (Morning=A, Early afternoon=B, Early night=C and Late night=D) and as a function of the time period of air exchange (Step 2: b, Step 3: c and Step 4: d). The following color code has been used: Black (outdoor ozone, OutA, OutB, OutC, OutD), Red (indoor ozone with openings open for 30 min - InAb, InBb, InCb, InDb), Blue (indoor ozone with openings closed for 15 min – InAc, InBc, InCc, InDc), Purple (indoor ozone with openings closed for 30 min – InAd, InBd, InCd, InDd).