We can all agree that we have not had a Harmattan this intense in Nigeria for years. I am actually enjoying the weather but the dust levels are quite high and that has translated to a number of people exhibiting varying flu symptoms.
A cheap and easy way to keep colds and minor allergies at bay is by incorporating a ginger drink in your diet. Benefits of Ginger can be found here. You can also find my recipe for Ginger-Lemon Tea here. The only improvement I would make is to grate the ginger or pound it in a mortar. Ginger is cheap and cheerful so there is really no reason why you shouldn't try it!
I have been "administering" a cup of ginger to my daughter and I every morning and evening. So far, no colds, no sinusitis. Take it hot or cold.
Happy Harmattan!