Ming-Yi Tsai, PhD, MSE

Affiliate Assistant Professor, Env. and Occ. Health Sciences (Primary department)
I became interested in the characterization of urban air quality after working in Beijing in the mid-1990s. I make measurements to model the spatial and temporal distribution of pollutants. I am particularly interested in bringing new methods and technologies into exposure assessment for air pollution health studies. In particular, I would like to increase the use of optical remote sensing and mobile monitoring approaches in air quality monitoring. I am also interested in developing appropriate air pollution monitoring approaches for cook stove intervention studies and integrated assessment of climate change impacts in "southern" countries.

Research Interests

  • Characterization of urban air quality by measurements and modeling; development of novel environmental exposure assessment tools for population-based studies; mobile monitoring approaches for air quality monitoring; extension of GIS-based land use regression modeling to high spatio-and-temporally resolved data; appropriate ambient/indoor air pollution monitoring for low-middle income countries (LMICs); exible archiving of real-time environmental data.


PhD, Environmental Health, University of Washington, 2007
MSE, Environmental Engineering, University of Washington, 1999
BSME, Mechanical Engr, Massachusetts Institute of Technology, 1993


ESCAPE - European study of cohorts for air pollution effects (http://www.escapeproject.eu/)

SAPALDIA - Swiss cohort study on air pollution and lung disease in adults (http://www.sapaldia.net/en/)
Exposure Science Group Projects:

Priority areas of research for our group at Swiss TPH include: vertical gradients of air
pollution in mid-sized European cities; development of integrated multi-pollutant systems for affordable real-time measurement of gases and particles in 'Southern' settings; smoking in public areas of Switzerland; use of novel techniques for Teflon filter analysis (oxidative potential, organic-functional groups); enhanced indoor positioning systems for better indoor exposure characterization.

Joint SARChi Chair: A Swiss-South African Joint Program on Global Environmental Health

In the framework of the Swiss-South Africa Joint Research Program for the Bilateral Re-search Chair in Global Environmental Health, Swiss TPH is supporting the air pollution monitoring, modeling, and exposure assessment of a study on school children’s health in four informal settlements of Western Cape Province in South Africa. This will be a cohort study investigating the effect of air pollution on asthma outcomes including asthma sym-ptoms, spirometry, fractional exhaled nitrogen oxide, and serial peak flow measurements. Air pollution monitoring will be conducted in two seasons (Nov. 2015 to Feb. 2016 and Jun. to Sep. 2016).

Monitoring will be done at 40 ’home-outdoor’ locations per neighborhood. One-week in-tegrated measurements are made for NO2, SO2, and PM2.5. Measurements are also done at the schools and a nearby routine air monitoring station. For modeling, one of the most important challenges is the collection of geographical information system (GIS) data for the Western Cape area and there is a need for building a layer(s) that describes local sources of air pollution within the four areas. Data from satellites can also be added to capture other background characteristics. With the measurements and relevant GIS data, land use regression models will be built for the different neighborhoods by season and annually. These models will be used in the epidemiological analyses to investigate health effects from air pollutants.

EXPOsOMICs: Enhanced exposure assessment and omic profiling for high priority environmental exposures in Europe (www.exposomicsproject.eu)

EXPOsOMICs aims to predict individual disease risk related to the environment in five European areas by characterizing the external and internal exposome for common expos-ures (air and water contaminants) during critical periods of life. Large amounts of health data from longitudinal cohorts in both children and adults, with detailed information on risk factors, confounders, and outcomes are not well linked with environmental exposure data. This project builds on the exposome concept, referring to the totality of environmen-tal exposures from conception onwards, by combining novel tools of exposure assessment (including sensors, smartphones, geo-referencing, satellites) and omic profiles in an agnostic search for new and integrated biomarkers. I, and the exposure science group, are respon-sible for the exposure sampling of volunteers (home and personal) as well as the mobile outdoor monitoring (2013-2014). We are using a mix of real-time instruments for UF P , PM2.5, BC, GPS-location, physical activity, and integrated filters to monitor exposure. All monitoring data have now been collected and data analysis and paper writing are on their way.

Swiss TPH Pilot Project Air Quality in Kaedi Mauritania

By bringing together faculty from both former institutes of the Swiss TPH, this pilot is one of the key projects to facilitate the merger and integration of two quite different research traditions. This air pollution study had two objectives: to characterize traffic impacts on a medium-sized city in West Africa and to measure the home environment impacts of cook stoves fueled primarily by solid fuels such as wood and biomass. For the outdoor campaign, 48-hr NO2 passive samplers were deployed at 40 locations throughout the city with the objective to capture the range of traffic intensities. For the home environment, 9 homes were measured with 48-hr NO2 & CO passive samplers in 3 areas: the cooking area, the indoor common area, and at the street; additionally, personal measurements on the main cook was also collected. During the 5-day study period (April 2011), a reference site was maintained where all measurements were simultaneously conducted. We found NO2 pollution from mobile sources to be modest with the highest levels along the principal axes. The home environment clearly indicated highest levels at the stoves and lowest levels in the common area, while personal measurements were between those levels. Most interestingly, the central site real-time PM monitor found very high (around 100 ug/m3) levels of PM2.5 in the absence of CO indicating that high ambient PM2.5 levels may result from neighborhood levels of cook stove emissions. A masters thesis was completed on land use regression modeling using outdoor NO2 in combination with available GIS and satellite data. This was one of the first land use regression models on the African continent (Gebreab et al. Spatial air pollution modeling for a West-African town. Geospatial Health, 2015).

ESCAPE: Exposure Monitoring & Modeling

European study of cohorts for air pollution effects (ESCAPE) was a multi-center European study on the long-term health effects of air pollution. Swiss TPH was a coordinating cen-ter for 8 of the 40 areas involved. I coordinated the air sampling for NO2, NOx, PM2.5 and PM10 (2008-2010), data QA/QC, and personally conducted all land use regression modeling, exposure assignment to cohort subjects in Basel, Geneva, Lugano, Vorarlberg, Verona, Pavia, and Varese. Additionally, I have also coordinated elemental analysis on all ESCAPE PM filters using x-ray fluorescence (XRF) and published a paper describing the distribution of elements within and across ESCAPE areas (Tsai et al. Spatial variation of PM elemental composition between and within 20 European study areas: Results of the ESCAPE project. Environment International, 2015).

SAPALDIA: Laboratory Infrastructure, Exposure Monitoring & Modeling

In support of exposure monitoring for the Swiss cohort study of air pollution and lung and cardiovascular disease in adults (SAPALDIA), I have expanded our laboratory facilities at Swiss TPH by: designing and installing a microbalance weighing chamber; acquiring additional sampling equipment; facilitated transfer of critical institutional knowledge from Prof. Sally Liu’s University of Washington group. Our exposure science group is currently modeling exposures to UFP, PM2.5, PM10, PMabs, NO2, PM elements for the SAPALDIA cohort. Our group also works closely with a number of Swiss federal & cantonal air mo-nitoring groups to conduct parallel measurements comparing our equipment to reference monitoring instruments. I continue to coordinate regular SAPALDIA air group meetings with our governmental partners to inform them about our collaborative work, discuss other projects, mutual concerns, and future collaborations.

Active LP-DOAS: Real-time NO2 Monitoring

In collaboration with the University of Heidelberg–Institute for Environmental Physics, we studied the time evolution of the vertical gradient of NO2 along a street canyon in Hei-delberg using a long-path differential optical absorption spectroscopy (LP-DOAS) system. In April 2009, real-time NO2 measurements were made over 2 weeks using the LP-DOAS operating in the visible blue light band to e

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