A chemical store has a volume of $15\ \text{m}^3$. A tray of ethoxyethane (molar mass $74.123\ \text{g/mol}$) is left open, and the liquid slowly evaporates. Ether vapour burns in air once it is $1.9\ \%$ of the volume of the air or more, and at this room temperature one mole of any vapour takes up $24.46\ \text{L}$. How many grams of ether must evaporate before the store air can burn?