If dust or aerosol is inhaled that already carries radon decay products, the deposition pattern of the decay products in the respiratory tract depends on the behaviour of the particles in the lungs. Smaller diameter particles diffuse further into the respiratory system, whereas the larger—tens to hundreds of micron-sized—particles often deposit higher in the airways and are cleared by the body's mucociliary staircase. Deposited radioactive atoms or dust or aerosol particles continue to decay, causing continued exposure by emitting energetic alpha radiation with some associated gamma radiation too, that can damage vital molecules in lung cells,[2] by either creating free radicals or causing DNA breaks or damage,[50] perhaps causing mutations that sometimes turn cancerous.