You can here to make a dusty picture by taking help of this step by step example.
Picture: Start this example with a fresh garden picture.
Noise: Take a new layer and fill color as you like, now go to Filter menu > Noise > Add noise and use same settings as given below.
You will get it.
Layer settings: Use same layer settings.
Decrease size: Use again layer settings and press Ctrl + T to decrease size as given below.
Gaussian blur: Go to Filter menu > Blur > Apply Gaussian blur.
You will have similar picture as given below.
Recommend the tutorial