Described herein are methods directed to the use of the nanodot taggants in detection and/or simulation scenarios. The nanodot taggants are based on quantum dots and may be engineered so as to have particular emission and or absorbance spectral characteristics. The nanodots are extremely small, i.e., on the order of nanometers in size, and thus do not, in some cases, behave as particles, but rather are able to be carried along and through structures like a gas.