If you are upwind, the smoke will become part of the image, illuminated by the fireworks. Automatic exposure doesn't work well with fireworks. Try a series of exposures of different bursts because there is a certain amount of luck involved. You might also use flash to illuminate foreground figures. You might also want to try increasing sensitivity, use exposure compensation, and try different combinations of aperture and shutter speed as well as those recommended here.
Fireworks can be dramatic, but are difficult to capture.
You need to experiment and a digital camera is perfect for that because you can instantly review your results. Candlelight provides a very warm glow to whatever it illuminates. Use automatic exposure at night if brightly lit areas take up most of the scene visible in your viewfinder. If they do not, use exposure compensation to reduce the exposure and darken the image so bright lights aren't overexposed. This picture of Chicago was taken just after sunset through an airliner window.