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Environmental and Occupational Health Doctoral Student Profiles

Rachit Sharma headshot

Rachit Sharma, MBBS, MPH

Degrees: MBBS from University of Health Sciences, Rohtak, India; MPH from Johns Hopkins University

Rachit's Focus: Rachit Sharma is interested in investigating the health effects of air pollution and climate change, particularly in urban settings, and understanding how various psychosocial stressors may modify such effects.

Prior to starting his doctoral training, Rachit was involved in the Delhi Air Pollution: Health and Effects study as a physician-researcher. The study aimed at establishing exposure-response relationships between air pollution and adverse birth outcomes and asthma in Delhi-National Capital Region, India.

Research Interests:

  • Air pollution and climate epidemiology
  • Psychosocial health
  • Urban health


Lizbeth Gomez Sharma headshot

Lizbeth Gomez, MPH

Degrees: BSc in Biology from The City College of New York; MPH in Environmental Health Sciences from Columbia University with a certificate in Molecular Epidemiology.

Lizbeth’s Focus: Lizbeth’s research focuses on the modification of clinical trial treatment efficacy by social and environmental co-exposure among asthma patients. Her work centers on understanding the role that the environment and lived experience may play in asthma medication efficacy.

Research Interests:

  • Air pollution
  • Asthma interventions
  • Mixed Methods
  • Social Determinants of Health
  • Community-based participatory research methods


  • Navas-Acien, A., Domingo-Relloso, A., Subedi, P., Riffo-Campos, A. L., Xia, R., Gomez, L., Haack, K., Goldsmith, J., Howard, B. V., Best, L. G., Devereux, R., Tauqeer, A., Zhang, Y., Fretts, A. M., Pichler, G., Levy, D., Vasan, R. S., Baccarelli, A. A., Herreros-Martinez, M., … Cole, S. A. (2021). Blood DNA Methylation and Incident Coronary Heart Disease: Evidence From the Strong Heart Study. JAMA Cardiology.
  • Navas-Acien Ana, Domingo-Relloso Arce, Tellez-Plaza Maria, Gomez Lizbeth, Herreros Miguel, Devereux Richard B, Baccarelli Andrea, Umans Jason G, Howard Barbara, Zhao Jinying, Tang WanYee, Haack Karin, Fallin M. Daniele, & Cole Shelley. (2020). Abstract MP31: Blood DNA Methylation Signatures of Incident Coronary Heart Disease: An Epigenome-wide Analysis in the Strong Heart Study.


Yun-Ting Yen headshot

Yun-Ting Yen, MS

Degrees: BS in Nutrition from Taipei Medical University, Taiwan; MS in Environmental and Occupational Health from National Taiwan University, Taiwan

Yun-Ting’s Focus: Yun-Ting uses epidemiology methods along with geospatial analysis to study how environmental exposures affect human health. Her work centers on reducing health disparities in urban communities.

Research Interests:

  • Environmental Exposures
  • Geospatial Analysis
  • Health Disparities
  • Urban Health
  • Social Determinants of Health
  • Risk Assessment

Professional Experience: Before starting her doctoral program, Yun-Ting worked at the GIS center at Academia Sinica in Taiwan. She collaborated in several research projects, including using GIS to study green space and type II diabetes, drug use in urban cities, and PM2.5 and mortality rates.


Ashley M. Geczik headshot

Ashley M. Geczik, MPH

Degrees: BS from Loyola University Maryland; MPH from Columbia University Mailman School of Public Health

Ashley's Focus: Ashley’s research is focused on how organizational safety climate is associated with occupational exposures and chronic disease outcomes among firefighters. Ashley’s research will help guide fire department leadership on ways to mitigate chronic disease risk. At Drexel, Ashley will be collaborating with the Firefighter Injury Research and Safety Trends (FIRST) Center.

In the five years Ashley has been an epidemiologist, she gained competencies in all aspects of the scientific research process: proposal writing, IRB, patient enrollment, data cleaning, analysis, and interpretation. At the NCI, Ashley studied hormonal and reproductive risk factors for cancer outcomes in men and women, producing published manuscripts and conference proceedings.

Research Interests:

  • Firefighter health
  • Occupational epidemiology
  • Chronic disease prevention
  • Cancer epidemiology

Professional Experience: Research Analyst at the National Cancer Institute

Awards and Honors: 2020 APHA OHS Section’s James Keogh Scholarship


  • Geczik AM, Kelly SP, Pfeiffer RM, Huang WY, Liao LM, Zhou CK, Brinton LA, Cook MB. Fatherhood Status in Relation to Prostate Cancer Risks in Two Large US-based Prospective Cohort Studies. Cancer Med. 2020 Nov 21. Epub ahead of print. PMID: 33219755.
  • Cook MB, Hurwitz LM, Geczik AM, Butler EN. An up-to-date assessment of U.S. prostate cancer incidence rates by stage and race: A novel approach combining multiple imputation with age- and delay-adjustment. Eur Urol. 2020 Oct 19. Epub ahead of print. PMID: 33092896.
  • Trabert B, Bauer DC, Buist DS, Cauley JA, Falk RT, Geczik AM, Gierach GL, Hada M, Hue TF, Lacey JV, LaCroix AZ, Tice JA, Xu X, Dallal CM, Briton LA. Association of Circulating Progesterone With Breast Cancer Risk Among Postmenopausal Women. JAMA Netw Open. 2020 Apr 1. PMID: 32329771.
  • Trabert B, Michels KA, Anderson GL, Brinton LA, Falk RT, Geczik AM, Harris HR, Pan K, Pfeiffer RM, Qi L, Rohan T, Wentzensen N, Xu X. Circulating androgens and postmenopausal ovarian cancer risk in the Women's Health Initiative Observational Study. Int J Cancer 2019; Jan 26 (E-pub). PMID: 30684389.
  • Samimi G*, Trabert B*, Geczik AM, Duggan MA**, Sherman ME**. Population frequency of serous tubal intraepithelial carcinoma (STIC) in clinical practice using SEE-Fim Protocol. *These authors contributed equally to this work. **These authors equally directed this work. JNCI Cancer Spectrum, Volume 2, Issue 4, Nov 2018. PMID: 31360879.

Contact: or on Twitter @AshleyGeczik

Dani Piontkowski headshot

Dani Piontkowski, MS

Degrees: BS in Environmental Engineering from Clarkson University; MS in Environmental Health Science from New York University

Dani's Focus: Dani’s research is centered around mental health and environmental exposures. She is interested in investigating associations between air pollution, temperature, and acute mental health outcomes. Of further interest is studying whether having a pre-existing mental health condition increases one’s risk of an adverse cardiovascular outcome when exposed to increased air pollution and temperature.

Research Interests:

  • Climate change
  • Air pollution
  • Mental health
  • Health disparities

Madison Raposa headshot

Madison Raposa, MS

Degrees: BA in Health Science from Stonehill College; MS in Population Health Research: Epidemiology from Boston University

Madison's Focus: Madison’s research is focused on mental health and occupational exposures in the fire service. She is interested in investigating associations between occupational stressors related to the coronavirus pandemic and mental health outcomes.

At Drexel, Madison will be collaborating with the Firefighter Injury Research & Safety Trends (FIRST) Center.

Research Interests:

  • Firefighter health
  • Mental health
  • Injury prevention
  • Occupational epidemiology

Awards and Honors: 2021-2022 Drexel Blue Graduate College Fellow

Learn more about environmental and occupational health research and learning opportunities available at Drexel Dornsife: