Yiqun Ma
Pre-doctoral Fellow, Climate Change and HealthAbout
Research
Publications
2025
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
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, kwaf147. PMID: 40663094, 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 reduction
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 outcomesLong-term exposure to wildfire 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 wildfire smoke PM2.5 and mortality in the contiguous United States. ISEE Conference Abstracts 2024, 2024 DOI: 10.1289/isee.2024.1154.Peer-Reviewed Original ResearchAir pollution changes due to COVID-19 lockdowns and attributable mortality changes in four countries
Ma Y, Nobile F, Marb A, Dubrow R, Kinney P, Peters A, Stafoggia M, Breitner S, Chen K. Air pollution changes due to COVID-19 lockdowns and attributable mortality changes in four countries. Environment International 2024, 187: 108668. PMID: 38640613, DOI: 10.1016/j.envint.2024.108668.Peer-Reviewed Original ResearchConceptsMeteorological normalization techniqueAir pollution changesFine particulate matterImprove air qualityEmission control strategiesCentral-southern ItalyPollution changesParticulate matterRegion-specific estimatesAir qualityMeteorological impactsAir pollutionPollutionCOVID-19 lockdownModeling approachAirCaliforniaMortality changesConcentrationJiangsuEmissionTime trendsLocal characteristicsChinaMatterShort-Term Exposure to Fine Particulate Matter and Nitrogen Dioxide and Mortality in 4 Countries
Ma Y, Nobile F, Marb A, Dubrow R, Stafoggia M, Breitner S, Kinney P, Chen K. Short-Term Exposure to Fine Particulate Matter and Nitrogen Dioxide and Mortality in 4 Countries. JAMA Network Open 2024, 7: e2354607. PMID: 38427355, PMCID: PMC10907920, DOI: 10.1001/jamanetworkopen.2023.54607.Peer-Reviewed Original ResearchConceptsShort-term exposure to air pollutionExposure to air pollutionFine particulate matterCross-sectional studyAir pollutionFixed-effects modelParticulate matterShort-term exposure to PM2.5Short-term exposure to fine particulate matterNO2 concentrationsExposure to fine particulate matterMortality rateNitrogen dioxideSignificant effect modificationDaily PM2.5 concentrationsTime-varying confoundersExposure to PM2.5Health outcomesEstimate associationsMortality dataEffect modificationPM2.5 concentrationsMain OutcomesDay-to-dayCentral-southern Italy
2023
Canadian Wildfire Smoke and Asthma Syndrome Emergency Department Visits in New York City
Chen K, Ma Y, Bell M, Yang W. Canadian Wildfire Smoke and Asthma Syndrome Emergency Department Visits in New York City. JAMA 2023, 330: 1385-1387. PMID: 37733685, PMCID: PMC10514869, DOI: 10.1001/jama.2023.18768.Peer-Reviewed Original ResearchRacial/ethnic disparities in PM2.5-attributable cardiovascular mortality burden in the United States
Ma Y, Zang E, Opara I, Lu Y, Krumholz H, Chen K. Racial/ethnic disparities in PM2.5-attributable cardiovascular mortality burden in the United States. Nature Human Behaviour 2023, 7: 2074-2083. PMID: 37653149, PMCID: PMC10901568, DOI: 10.1038/s41562-023-01694-7.Peer-Reviewed Original ResearchConceptsNon-Hispanic White peopleCVD deathMortality burdenNon-Hispanic black peopleCardiovascular disease mortality ratesDisease mortality ratesNon-Hispanic blacksRace/ethnicityMortality rateLong-term exposureWhite peopleEthnic disparitiesHealth benefitsHispanic peopleSignificant differencesBurdenDeathUS countiesEthnic groupsAbsolute disparityAssociationExposureEthnic minoritiesDisparitiesAmbient fine particulate matter (PM2.5) concentrations
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