Black dust around edges of carpets

[Rafan]

In every bedroom we have cream carpets. they all have black dust on the edges and door ways, even on the door ways to fitted wardrobes. On the landing its on the door way to the airing cupboard. Anyone know why this is happening and what we can do to stop it ruining more new carpets?

[stoneyboy]

Rafan,
It's air being blown in from outside, the edges of the carpet are acting as a filter. Lift the edges of the carpets and fill the gap below the skirting.
end

[Rafan]

Thank you we will give it a go :)