World's Best Scientists 2026 revealed!

D-Index & Metrics

Environmental Sciences

D-Index
47
Citations
7677
World Ranking
5834
National Ranking
2125

Engineering and Technology

D-Index
47
Citations
9920
World Ranking
4797
National Ranking
1376

H. Christopher Frey publication distribution in Engineering and Technology in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Engineering and Technology in 2026. The highlighted bar marks where H. Christopher Frey sits on this spectrum.

38–47 publications: 20 scientists 48–57 publications: 35 scientists 58–67 publications: 96 scientists 68–77 publications: 135 scientists 78–87 publications: 190 scientists 88–97 publications: 259 scientists 98–107 publications: 283 scientists 108–117 publications: 369 scientists 118–127 publications: 341 scientists 128–137 publications: 386 scientists 138–147 publications: 372 scientists 148–157 publications: 457 scientists 158–167 publications: 415 scientists 168–177 publications: 407 scientists 178–187 publications: 421 scientists 188–197 publications: 378 scientists 198–207 publications: 403 scientists 208–217 publications: 317 scientists 218–227 publications: 346 scientists 228–237 publications: 321 scientists 238–247 publications: 260 scientists 248–257 publications: 280 scientists 258–267 publications: 240 scientists 268–277 publications: 214 scientists 278–287 publications: 242 scientists 288–297 publications: 203 scientists 298–307 publications: 166 scientists 308–317 publications: 154 scientists 318–327 publications: 175 scientists 328–337 publications: 159 scientists 338–347 publications: 99 scientists 348–357 publications: 131 scientists 358–367 publications: 106 scientists 368–377 publications: 118 scientists 378–387 publications: 97 scientists 388–397 publications: 108 scientists 398–407 publications: 82 scientists 408–417 publications: 71 scientists 418–427 publications: 64 scientists 428–437 publications: 55 scientists 438–447 publications: 54 scientists 448–457 publications: 60 scientists 458–467 publications: 47 scientists 468–477 publications: 40 scientists 478–487 publications: 30 scientists 488–497 publications: 29 scientists 498–507 publications: 38 scientists 508–517 publications: 40 scientists 518–527 publications: 32 scientists 528–537 publications: 23 scientists 538–547 publications: 28 scientists 548–557 publications: 23 scientists 558–567 publications: 19 scientists 568–577 publications: 16 scientists 578–587 publications: 17 scientists 588–597 publications: 18 scientists 598–607 publications: 22 scientists 608–617 publications: 15 scientists 618–627 publications: 9 scientists 628–637 publications: 11 scientists 638–647 publications: 21 scientists 648–657 publications: 12 scientists 658–667 publications: 9 scientists 668–677 publications: 11 scientists 678–687 publications: 9 scientists 688–697 publications: 6 scientists 698–707 publications: 14 scientists 708–717 publications: 7 scientists 718–727 publications: 8 scientists 728–737 publications: 10 scientists 738–747 publications: 9 scientists 748–757 publications: 5 scientists 758–767 publications: 5 scientists 768–777 publications: 11 scientists 778–787 publications: 7 scientists 788–797 publications: 2 scientists 798–803 publications: 4 scientists 804+ publications: 100 scientists
38 publications 804+

This scientist: 210 publications — 52nd percentile

52% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 804 publications or more.

H. Christopher Frey D-index placement in Engineering and Technology in 2026

The chart shows the D-index (discipline H-index) distribution of Engineering and Technology scientists ranked by Research.com in 2026. The highlighted bar marks where H. Christopher Frey sits on this spectrum.

30 D-Index: 59 scientists 31 D-Index: 114 scientists 32 D-Index: 129 scientists 33 D-Index: 189 scientists 34 D-Index: 200 scientists 35 D-Index: 262 scientists 36 D-Index: 311 scientists 37 D-Index: 312 scientists 38 D-Index: 350 scientists 39 D-Index: 385 scientists 40 D-Index: 348 scientists 41 D-Index: 362 scientists 42 D-Index: 426 scientists 43 D-Index: 380 scientists 44 D-Index: 310 scientists 45 D-Index: 341 scientists 46 D-Index: 301 scientists 47 D-Index: 306 scientists 48 D-Index: 271 scientists 49 D-Index: 246 scientists 50 D-Index: 210 scientists 51 D-Index: 253 scientists 52 D-Index: 213 scientists 53 D-Index: 221 scientists 54 D-Index: 195 scientists 55 D-Index: 186 scientists 56 D-Index: 170 scientists 57 D-Index: 167 scientists 58 D-Index: 166 scientists 59 D-Index: 144 scientists 60 D-Index: 152 scientists 61 D-Index: 141 scientists 62 D-Index: 138 scientists 63 D-Index: 131 scientists 64 D-Index: 118 scientists 65 D-Index: 114 scientists 66 D-Index: 119 scientists 67 D-Index: 95 scientists 68 D-Index: 87 scientists 69 D-Index: 77 scientists 70 D-Index: 89 scientists 71 D-Index: 69 scientists 72 D-Index: 54 scientists 73 D-Index: 46 scientists 74 D-Index: 55 scientists 75 D-Index: 54 scientists 76 D-Index: 49 scientists 77 D-Index: 53 scientists 78 D-Index: 46 scientists 79 D-Index: 28 scientists 80 D-Index: 39 scientists 81 D-Index: 36 scientists 82 D-Index: 24 scientists 83 D-Index: 26 scientists 84 D-Index: 36 scientists 85 D-Index: 18 scientists 86 D-Index: 25 scientists 87 D-Index: 19 scientists 88 D-Index: 26 scientists 89 D-Index: 27 scientists 90 D-Index: 23 scientists 91 D-Index: 15 scientists 92 D-Index: 12 scientists 93 D-Index: 9 scientists 94 D-Index: 15 scientists 95 D-Index: 10 scientists 96 D-Index: 13 scientists 97 D-Index: 13 scientists 98 D-Index: 9 scientists 99 D-Index: 7 scientists 100 D-Index: 7 scientists 101 D-Index: 8 scientists 102 D-Index: 7 scientists 103 D-Index: 7 scientists 104 D-Index: 9 scientists 105 D-Index: 6 scientists 106 D-Index: 9 scientists 107+ D-Index: 99 scientists
30 D-Index 107+

This scientist: 47 D-Index — 52nd percentile

52% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 107 D-Index or more.

Overview

H. Christopher Frey is affiliated with North Carolina State University in the United States. Their research spans multiple fields and subfields, including Environmental Science, Engineering, and Social Sciences. Among key subfields are Health, Toxicology and Mutagenesis, Automotive Engineering, Transportation, Renewable Energy, Sustainability and the Environment, and General Economics, Econometrics and Finance.

The scientist's main topics of work cover a variety of areas related to environmental and transportation issues. These include:

  • Vehicle emissions and performance
  • Air Quality and Health Impacts
  • Transportation Planning and Optimization
  • Energy, Environment, and Transportation Policies
  • Global trade and economics
  • Air Quality Monitoring and Forecasting
  • Global Energy Security and Policy

Frequent co-authors collaborating on research include:

  • Tongchuan Wei
  • Alexis K.H. Lau
  • Weichang Yuan
  • Nicolle S. Tulve
  • Sean J. Paul

Key publication venues for Frey's work include:

  • Energies
  • The Science of The Total Environment
  • Transportation Research Part D Transport and Environment
  • Environmental Science & Technology
  • Transportation Research Record Journal of the Transportation Research Board

Recent papers authored or co-authored by H. Christopher Frey illustrate a diverse range of topics and interdisciplinary approaches. Selected examples include:

  • "Combined effects of increased O3 and reduced NO2 concentrations on short-term air pollution health risks in Hong Kong" (2020), published in Environmental Pollution
  • "The Need for a Tighter Particulate-Matter Air-Quality Standard" (2020), published in New England Journal of Medicine
  • "Potential for metro rail energy savings and emissions reduction via eco-driving" (2020), published in Applied Energy
  • "Variability in Measured Real-World Operational Energy Use and Emission Rates of a Plug-In Hybrid Electric Vehicle" (2020), published in Energies
  • "Factors affecting variability in gaseous and particle microenvironmental air pollutant concentrations in Hong Kong primary and secondary schools" (2020), published in Indoor Air

In addition to journal papers, Frey has contributed to book publications. One notable work is titled World Trade Law and the Emergence of International Electricity Markets, published by Springer International Publishing in 2022.

Best Publications

  • Probabilistic Techniques in Exposure Assessment: A Handbook for Dealing with Variability and Uncertainty in Models and Inputs

    Alison C. Cullen;H. Christopher Frey

  • Identification and Review of Sensitivity Analysis Methods

    H. Christopher Frey;Sumeet R. Patil

  • On-Road Measurement of Vehicle Tailpipe Emissions Using a Portable Instrument

    H. Christopher Frey;Alper Unal;Nagui M. Rouphail;James D. Colyar

  • Fuel use and emissions comparisons for alternative routes, time of day, road grade, and vehicles based on in-use measurements.

    H. Christopher Frey;Kaishan Zhang;Nagui M. Rouphail

  • Uncertainties in predicted ozone concentrations due to input uncertainties for the UAM-V photochemical grid model applied to the July 1995 OTAG domain

    Steven R Hanna;Zhigang Lu;H Christopher Frey;Neil Wheeler

  • A Vehicle-Specific Power Approach to Speed- and Facility-Specific Emissions Estimates for Diesel Transit Buses

    Haibo Zhai;H. Christopher Frey;Nagui M. Rouphail

  • Comparing real-world fuel consumption for diesel- and hydrogen-fueled transit buses and implication for emissions

    H. Christopher Frey;Nagui M. Rouphail;Haibo Zhai;Tiago L. Farias

  • A review of factors impacting exposure to PM2.5, ultrafine particles and black carbon in Asian transport microenvironments

    Prashant Kumar;Prashant Kumar;Allison P. Patton;John L. Durant;H. Christopher Frey

  • Real-World In-Use Activity, Fuel Use, and Emissions for Nonroad Construction Vehicles: A Case Study for Excavators

    Saeed Abolhasani;H. Christopher Frey;Kangwook Kim;William Rasdorf

  • Comprehensive Field Study of Fuel Use and Emissions of Nonroad Diesel Construction Equipment

    H. Christopher Frey;William Rasdorf;Phil Lewis

  • Coal blending optimization under uncertainty

    Jhih-Shyang Shih;H.Christopher Frey

  • Road grade estimation for on-road vehicle emissions modeling using light detection and ranging data.

    Kaishan Zhang;H. Christopher Frey

  • Assessing methods for comparing emissions from gasoline and diesel light-duty vehicles based on microscale measurements

    Margarida C. Coelho;H. Christopher Frey;Nagui M. Rouphail;Haibo Zhai

  • Quantitative Analysis of Uncertainty and Variability in Environmental Policy Making

    H. Christopher Frey

  • Road grade quantification based on global positioning system data obtained from real-world vehicle fuel use and emissions measurements

    Behdad Yazdani Boroujeni;H. Christopher Frey

  • Characterizing, simulating, and analyzing variability and uncertainty: An illustration of methods using an air toxics emissions example

    H. Christopher Frey;David S. Rhodes

  • Methods for Characterizing Variability and Uncertainty : Comparison of Bootstrap Simulation and Likelihood-Based Approaches

    H. Christopher Frey;David E. Burmaster

  • Speed- and Facility-Specific Emission Estimates for On-Road Light-Duty Vehicles on the Basis of Real-World Speed Profiles

    H Christopher Frey;Nagui M Rouphail;Haibo Zhai

  • Evaluation of numerical models for simulation of real-world hot-stabilized fuel consumption and emissions of gasoline light-duty vehicles

    C.M. Silva;T.L. Farias;H. Christopher Frey;Nagui M. Rouphail

  • Trends in onroad transportation energy and emissions.

    H. Christopher Frey

  • Requirements and Incentives for Reducing Construction Vehicle Emissions and Comparison of Nonroad Diesel Engine Emissions Data Sources

    Phil Lewis;William J Rasdorf;H Christopher Frey;Shih-hao Pang

Frequent Co-Authors

Nagui M. Rouphail
Nagui M. Rouphail North Carolina State University
Edward S. Rubin
Edward S. Rubin Carnegie Mellon University
Alexis K.H. Lau
Alexis K.H. Lau Hong Kong University of Science and Technology
Shannon L. Bartelt-Hunt
Shannon L. Bartelt-Hunt University of Nebraska–Lincoln
Prashant Kumar
Prashant Kumar University of Surrey
Urmila M. Diwekar
Urmila M. Diwekar University of Illinois at Chicago
Pankaj K. Agarwal
Pankaj K. Agarwal Duke University
Howard H. Chang
Howard H. Chang Emory University
Jimmy Chi Hung Fung
Jimmy Chi Hung Fung Hong Kong University of Science and Technology
Lee-Ann Jaykus
Lee-Ann Jaykus North Carolina State University

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