You need to choose the proper size of your pollution mask. When making a purchase, make sure that the mask is properly adjusted. Well-adjusted, tightly fitting mask will provide better protection against pollution.
The Broyx masks are available in different sizes:
M – designed for users with thin to medium face. Head circumference 48-56 cm, height from the bridge of nose to the chin approx. 14 cm.
L – designed for users with medium to wide face. Head circumference 52-60cm, height from the bridge of nose to the chin approx. 15 cm.