Unger joined Goddard Space Flight Center where she worked on air pollution and the impact of climate change on air quality.[3] Her research involved modelling the emissions from future industries.[3] Industries commonly burn fossil fuels that release carbon dioxide, which can result in global warming, but they also release sulphates that enter the atmosphere as aerosols.[4] These aerosols can cause the atmosphere to cool by blocking out heat from the sun and modifying the clouds so that they reflect more heat back to space.[4] She identified that until 2050 road vehicle emissions will dominate human emissions, but after then power sector emissions will take the lead.[3][5]