NIST has supported research characterizing ultrafine particle sources and dynamics for more than a decade. Over 90 % of ultrafine particles (UFP) produced by stovetop cooking on both gas and electric stoves were <10 nm in diameter. Emission rates of up to 1014 min-1 were noted. Coagulation was a dominant removal mechanism and was modeled with some success. Kitchen exhaust fan efficiencies varied from <10 % for particles <5 nm to nearly 100 % for particles >10 nm. Using the NIST test house, penetration coefficients and deposition rates were estimated under real-world conditions for particles in closed-window and open-window configurations. Infiltration factors using dedicated automated air change rate measurements varied from 0.02 for the smallest (<5 nm) particles to >0.5 for larger (30 nm to 100 nm) sizes.