Dr. Karaca’s main research area lies in a multidisciplinary civil and environmental engineering area by focusing on sustainable civil infrastructure and built environment research. He has been involved in research on the cutting-edge side of the domain, addressing the urgent requirements to develop materials, designs, and methods for resilient infrastructure and urban services and green technology solutions in cities / urban systems in developed and developing countries. He has worked on research projects related to urban air pollution management and control, future utility systems designs, and sustainability assessment civil infrastructure projects in the UK, Turkey, the USA, and Kazakhstan.

The majority of Dr. Karaca’s previous research and publications are related to sustainable civil infrastructure research is increasingly a key priority in engineering practices. He was involved in the body of research, addressing the urgent need to develop materials, designs, and methods to ensure the sustainability of future civil infrastructure needs. For example, “All in one” utility infrastructure solutions for future cities were suggested to overcome the aging civil infrastructure problems of Europe. Sustainable and green building solution requirements and novel sustainability assessment tools (e.g., RSAM, PANSUST) have been developed and assessed for Central Asian countries and cities. These studies also demonstrate the civil infrastructure design and management policy and current and future commercial implications associated with these findings. 

Another group of his previous research and publications directly addressed urban air quality problems. By applying source identification with a receptor modeling approach; and local, regional, and global transportation of the air pollutants, he has made a siginificant contribution to the literature. He has published several papers dealing with different sizes of urban agglomerations, from megacities to small communities. These publications document the governing mechanisms of urban air pollution sources, including traffic, industry, power generation, and transportation mechanisms, including long-range transportation from distant locations. They provide a key understanding of urbanization problems, so they are related to sustainability, too. Some of them also provided case study-based evidence on the impacts of cities on local, regional, and long-range destinations. They have made a significant contribution to the literature and become leading research topics. For example, the chemical composition of fine and coarse atmospheric particles in the megacity atmosphere in Istanbul and a coal industry city, Zonguldak; long-range transportation of mineral dust and invasive bioaerosols in different seasons over the Marmara region; environmental impacts of the COVID-19 pandemic in large cities including Tehran and Almaty; the effect of atmospheric circulation patterns over Central Asia, are some of the significant research achievements. By providing evidence and case study-based measurements, this body of work has changed the understanding of the source profiles in many cities. For example, recently, it has been supposed that the primary source of air pollution in Almaty, Kazakhstan, was believed to be vehicle emissions. Still, our recent findings changed this opinion that the primary source in the city is the coal combustion in the combined urban power and heat plants.

In addition to the contributions described above, He was involved in other research activities with a team of collaborators. He was involved in projects dealing with the impacts of air pollution on humans, such as public health, public awareness, personal well-being, and non-human effects such as on cultural heritage, built environment, and ecosystem. These studies emphasized the pathways in pollution impact, predominantly related to atmospheric particles. This body of work can be used to mitigate the effects of air pollution, especially in the form of airborne particles. 

Dr. Karaca's teaching interests include Environmental Engineering, Water Resources Engineering, Building Sustainability, and Management of Civil Infrastructures.

During the past five years at NU, He has developed and taught the following courses (13):

1. 1. Environmental Chemistry*
   2. Environmental Engineering*
   3. Project Management
   4. Sustainable Development*
   5. Hydraulics*
   6. Environmental Systems*
   7. Environmental Modeling Development*
   8. Construction Management and Practice*
   9. Individual Research Projects in Civil Engineering
   10. Green Building - Concept, Design, Construction, and Operation*
   11. Hydraulics and Hydrology*
   12. Water Supply and Distribution Management*
   13. Fluid Mechanics I*

He has constantly delivered two courses each semester as required by SEDS, NU.

According to the program outcomes and content requirements, these courses were either new (indicated with *) or redesigned/updated. Around 30-90 Engineering students had enrolled in undergraduate courses (for the Project management course: all the students, around 300 from the same cohort in SEDS’ took it), while the graduate courses were among the most populated ones (e.g., with 20 students maximum capacity). 

In addition to that, CEE recently opened a new discipline, “Water Resources Engineering.” Dr. Karaca is the leading and only professor currently teaching in this discipline. It includes two main courses (Fluid Mechanics I* and Hydraulics and Hydrology*) and two elective courses (Water Systems and Structure*s and Water Supply and Distribution Management*). During the last two years, He developed the contents for three of these courses (Hydraulics and Hydrology*, Water Supply and Distribution Management* and Fluid Mechanics*) and delivered them in 2020 and 2021.