Yiqun Ma
Pre-doctoral Fellow, Climate Change and HealthAbout
Research
Publications
2026
Spatial heterogeneity in synergistic effects of extreme heat and NO2 exposures on cardiorespiratory hospitalizations in California.
Ma Y, Chen C, Aguilera R, Gershunov A, Jerrett M, Connolly R, Marlier M, Benmarhnia T. Spatial heterogeneity in synergistic effects of extreme heat and NO2 exposures on cardiorespiratory hospitalizations in California. Epidemiology 2026 PMID: 41790999, DOI: 10.1097/ede.0000000000001970.Peer-Reviewed Original ResearchEffects of extreme heatSynergistic health effectsCardiorespiratory hospitalizationsNO2 exposureCase-crossover analysisDevelopment of targeted intervention strategiesLow socioeconomic statusEthnic minority residentsHigh air pollution levelsExtreme heatSpatial heterogeneitySocioeconomic statusExcess riskHospital dataAir pollution levelsCalifornia DepartmentMeta-RegressionRERISpatial Bayesian hierarchical modelIntervention strategiesMinority residentsHospitalVulnerable communitiesCommunity characteristicsBayesian hierarchical modelCo-occurring climate hazards and compound health effects in California: a scoping review
Connolly R, Ma Y, Villanueva M, Schollaert C, Bekker C, Jerrett M, Benmarhnia T, Marlier M. Co-occurring climate hazards and compound health effects in California: a scoping review. Environmental Research Health 2026, 4: 012001. DOI: 10.1088/2752-5309/ae3ed9.Peer-Reviewed Original ResearchHealth outcomesAdverse health outcomesHealth effectsExposure assessment techniquesClimate hazardsWeb of ScienceEffects of climate stressorsUnderserved communitiesScoping ReviewBirth outcomesDisadvantaged populationsClimatic eventsEquity impactsEnvironmental justice implicationsDiverse populationsEffects of climatic eventsClimate stressorsWildfire smokeAir pollutionPubMed databaseVulnerable communitiesClimate exposureSpatial variabilityCo-exposureCalifornia populationDaytime and nighttime heatwave intensity and acute care utilization for mental and neurological disorders in California
Ma Y, Guirguis K, Jones-Ngo C, Teyton A, Brown H, Charlson F, Jerrett M, Connolly R, Gershunov A, Marlier M, Benmarhnia T. Daytime and nighttime heatwave intensity and acute care utilization for mental and neurological disorders in California. Environmental Research Health 2026, 4: 011001. PMID: 41502548, PMCID: PMC12771553, DOI: 10.1088/2752-5309/ae3128.Peer-Reviewed Original ResearchAcute care utilizationCare utilizationPost-traumatic stress disorderNeurological disordersAnxiety disordersDepressive disorderStress disorderBipolar disorderConduct disorderMental disordersZip code tabulation areasPublic health practitionersCase-crossover studyDisordersHealth practitionersParkinson's diseaseAlzheimer's diseaseHeatwave intensityNeurological healthDetrimental impactAssociations of daytimeSchizophreniaAnxietySubtypesHeatwave exposure
2025
Disparities in NO2-related health burden prevalent across race-ethnicity and income groups in the United States
Chu L, Ma Y, Zang E, Huang L, Chen K. Disparities in NO2-related health burden prevalent across race-ethnicity and income groups in the United States. One Earth 2025, 8: 101387. DOI: 10.1016/j.oneear.2025.101387.Peer-Reviewed Original ResearchHigh-income countiesRace-EthnicityNon-Hispanic black populationHealth burdenRacial-ethnic disparitiesRace-ethnic groupsIncome groupsLow-income countiesQuasi-Poisson regressionRacial-ethnic minoritiesMortality disparitiesUnited StatesHealthcare strategiesMortality burdenDescriptive statisticsRelative riskDisparitiesBlack populationNO2 exposureBurdenMortality rateCountyIncomeTargeted policiesMortalityTwo-stage interrupted time series analysis with machine learning: evaluating the health effects of the 2018 wildfire smoke event in San Francisco County as a case study
Dey A, Ma Y, Carrasco-Escobar G, Han C, Rerolle F, Benmarhnia T. Two-stage interrupted time series analysis with machine learning: evaluating the health effects of the 2018 wildfire smoke event in San Francisco County as a case study. American Journal Of Epidemiology 2025, 194: 2936-2944. PMID: 40663094, PMCID: PMC12527249, DOI: 10.1093/aje/kwaf147.Peer-Reviewed Original ResearchNeural network autoregressionPost-event periodCase studyIT frameworkRandomized Controlled TrialsInterrupted time seriesNatural experimentSan Francisco CountyIdentification strategyEthical issuesSmoke eventsWildfire smoke eventsCounterfactual scenariosMachine learning algorithmsRespiratory hospitalizationsInterrupted time series analysisWeather eventsHealth policy evaluationCausal effectsHyperparameter tuningLearning algorithmsTime series analysisQuasi-experimental designMachine learningPolicy evaluationShort-term exposure to ambient nitrogen dioxide and fine particulate matter and cause-specific mortality: A causal modeling approach in four regions
Marb A, Ma Y, Nobile F, Dubrow R, Kinney P, Stafoggia M, Chen K, Peters A, Breitner S. Short-term exposure to ambient nitrogen dioxide and fine particulate matter and cause-specific mortality: A causal modeling approach in four regions. Environmental Pollution 2025, 372: 126059. PMID: 40089139, DOI: 10.1016/j.envpol.2025.126059.Peer-Reviewed Original ResearchParticulate matterAir pollutionDaily NO2 anShort-term air pollution exposureNitrogen dioxideDaily air pollution dataExposure to NO2Effects of air pollutionShort-term exposure to NO2 anFine particulate matterTwo-pollutant modelsExposure to ambient nitrogen dioxideAmbient air pollutionAmbient particulate matterAir pollution dataAir pollution exposureCause-specific mortality ratesAmbient nitrogen dioxideRural populationCause-specific mortalityRespiratory mortality ratesMortality rateCause-specific deathCardiovascular mortality ratesPollution exposureEffect of Air Pollution Reductions on Mortality During the COVID-19 Lockdowns in Early 2020.
Chen K, Ma Y, Marb A, Nobile F, Dubrow R, Stafoggia M, Breitner S, Kinney P. Effect of Air Pollution Reductions on Mortality During the COVID-19 Lockdowns in Early 2020. Research Report 2025, 2025: 1-47. PMID: 40551404, PMCID: PMC12185919.Peer-Reviewed Original ResearchConceptsAir pollution changesAir pollutionPollution changesShort-term exposure to PM2.5Air qualityExposure to PM2.5Natural-causeMeteorological normalization techniqueFine particulate matterDaily air pollutionImprove air qualityAir pollutant emissionsAir pollution reductionEmission control strategiesSouthern ItalyQuantify changesAir pollution-mortality relationshipPollution-mortality relationshipCOVID-19 lockdownShort-term exposureNOParticulate matterMeteorological impactsNitrogen dioxidePollution reductionInterrupted Time Series Analysis in Environmental Epidemiology: A Review of Traditional and Novel Modeling Approaches
Ma Y, Benmarhnia T. Interrupted Time Series Analysis in Environmental Epidemiology: A Review of Traditional and Novel Modeling Approaches. Current Environmental Health Reports 2025, 12: 50. PMID: 41324811, PMCID: PMC12669373, DOI: 10.1007/s40572-025-00517-3.Peer-Reviewed Original ResearchConceptsEnvironmental epidemiologyInterrupted time series analysisPublic health interventionsHealth interventionsMachine learning algorithmsReal-world settingsReal-world case studyMachine learning modelsRespiratory hospitalizationsWildfire smoke eventsAnnotated datasetsLearning algorithmsCausal inferenceComplex temporal patternsIT designLearning modelsWildfire smokeEnvironmental healthIT approachEpidemiologySan FranciscoTreatment effectsTime series analysisComparative analysis of methodsSmoke events
2024
Applying a two-stage generalized synthetic control approach to quantify the heterogeneous health effects of extreme weather events: A 2018 large wildfire in California event as a case study
Letellier N, Hale M, Salim K, Ma Y, Rerolle F, Schwarz L, Benmarhnia T. Applying a two-stage generalized synthetic control approach to quantify the heterogeneous health effects of extreme weather events: A 2018 large wildfire in California event as a case study. Environmental Epidemiology 2024, 9: e362. PMID: 39744585, PMCID: PMC11692959, DOI: 10.1097/ee9.0000000000000362.Peer-Reviewed Original ResearchWildfire seasonHealth impactsHealth effectsEffects of wildfire smokeUnexposed countiesHealth outcomesEffect modificationCalifornia wildfire seasonCounty-level sociodemographic characteristicsCounty-level socioeconomic variablesImpacts of climate hazardsRespiratory hospitalizationsWeather eventsNegative health outcomesTime-varying confoundersRandom-effects meta-regressionWildfire smokeCalifornia wildfiresWildfireExtreme weather eventsClimate changeClimate hazardsSociodemographic characteristicsPopulation subgroupsCirculatory healthLong-term exposure to wildland fire smoke PM2.5 and mortality in the contiguous United States
Ma Y, Zang E, Liu Y, Wei J, Lu Y, Krumholz H, Bell M, Chen K. Long-term exposure to wildland fire smoke PM2.5 and mortality in the contiguous United States. Proceedings Of The National Academy Of Sciences Of The United States Of America 2024, 121: e2403960121. PMID: 39316057, PMCID: PMC11459178, DOI: 10.1073/pnas.2403960121.Peer-Reviewed Original ResearchConceptsWildland firesContiguous United StatesNonaccidental mortalityExposure to ambient fine particlesSmoke PMWildland fire smokeMoving average concentrationsAmbient fine particlesLong-term exposureAverage concentrationSmoke PMHealth risksFine particlesFire smokeTemporal confoundingHealth effectsKidney disease mortalityChronic kidney disease mortalityPublic health actionFireMortality rateUnited StatesDisease mortalityHealth actionsMortality outcomes
Academic Achievements & Community Involvement
News
News
- September 24, 2024
Long-term exposure to wildfire smoke associated with higher risk of death
- August 21, 2024
Wildfires: what you need to know to stay safe
- August 19, 2024
Very hot weather is hazardous to your health, but there are ways to stay safe
- October 05, 2023
Canadian wildfire smoke associated with increased asthma cases in NYC