1. How Can TEMPO Contribute to Air Pollution Health Effects Research
Yang Liu, Ph.D.
Emory University, Rollins School of Public Health
1st Tropospheric Emissions: Monitoring of Pollution
(TEMPO) Applications Workshop
July 12-13, 2016
Huntsville, AL

2. The health effects of air pollutants
Outline
The health effects of air pollutants
PM2.5, O3, NO2, and SO2
Based on EPA’s Integrated Science Assessments
Satellite data used in air quality health research
Based on personal experience and peer-reviewed literature
TEMPO’s potentials
In terms of air pollution exposure modeling
Personal opinion based on my limited knowledge of TEMPO

3. The EPA ISA
The Integrated Science Assessments (ISA) provide a synthesis and evaluation of the most policy-relevant science that builds the scientific foundation for the periodic review of the NAAQS.
Determination
Interpretation
Research Needs
Causal
Sufficient and conclusive evidence
Not much research is needed in the US
Likely causal
Sufficient evidence but with uncertainties
More research is needed
Suggestive
Limited evidence

4. Health Effects of PM2.5
Acute effects (e.g., daily asthma ED visits linked with daily PM2.5 level)
Chronic effects (e.g., heart attacks linked with long-term PM2.5 level)
Health effects caused by short-term exposure to PM2.5, which is based on a daily standard, include:
1. Premature death, especially death related to heart and lung diseases
2. Increased hospital admissions and emergency department visits for cardiovascular effects, such as non-fatal heart attacks and strokes.
3. Increased hospital admissions and emergency department visits for respiratory effects, such as asthma attacks, coughing, wheezing and shortness of breath.
4. Reduced lung function, especially in children and people with lung diseases, such as asthma.
Health effects caused by long-term exposure to PM2.5, which is based on an annual standard, include:
Premature death, especially related to heart disease
Cardiovascular effects, such as heart attacks and strokes
Reduced lung development as well as the development of chronic respiratory diseases, such as asthma, in children
Some studies also suggest that long-term PM2.5 exposures may be linked to cancer and to harmful developmental and reproductive effects, such as infant mortality and low birth weight.
Source: EPA EPA/600/R-08/139F, 2009

5. Health Effects of O3 Acute exposure (i.e., hours, days, weeks):
Source: EPA 600/R-10/076F, 2013

6. Health Effects of O3
Chronic exposure (i.e., months to years):

7. Health Effects of NO2 Acute exposure (minutes up to 1 month)
Source: EPA/600/R-14/006, 2015

8. Health Effects of NO2
Chronic exposure (i.e., > 1 month to years):

9. Health Effects of SO2
Source: EPA/600/R-15/066, 2015

10. Summary of Research Needs
Acute Exposure
(i.e, hrs – months)
Chronic Exposure
(i.e., seasons - yrs)
PM2.5
Causal / Likely
Causal / Likely/ Suggestive O3
Likely / Suggestive
NO2
Causal / Suggestive
SO2
Suggestive

11. Question: how Can tempo help address these research needs?
Good news: all of these air pollutants need more research on their health effects!
Question: how Can tempo help address these research needs?

12. People will figure out ways to use tempo data no matter what
Bottom line:
People will figure out ways to use tempo data no matter what

13. Key Factors in Exposure Modeling
Study duration
Means sample size in acute studies
Makes more accurate exposure estimates in chronic studies
Temporal resolution
Acute study NEEDS accurate short-term fluctuation of exposure
Chronic study cares less about temporal resolution
Spatial resolution
Acute study can get more accurate effect estimates with high resolution exposure data
Chronic study NEEDS accurate spatial gradient of exposure
Accuracy and spatial coverage
Important to both study types

14. Health Applications of Current Sensors
Well established for PM2.5 (not sure if in the upcoming ISA)
A lot of methods proposed to convert AOD to PM2.5 and fill data gaps
Have been used to drive both acute and chronic effects studies in the US and worldwide
Spatial resolution: as high as 1 km
Applications of other species are lacking due to
Poor spatial resolution (e.g., SO2 and NO2)
Poor sensitivity in boundary layer (e.g., O3)
Low correlation with ground observations

15. TEMPO’s Capabilities Duration: >= 2 years Temporal resolution:
Hourly NO2 and aerosol
0–2 km O3 every 2 hours (possibly at 1 hour at target locations)
SO2 sampled every 3 hours
Spatial resolution: required at 8.4 x 4.7 km2 (possibly at 2.1 x 4.7 km2 at target locations)
Coverage: greater North America
Accuracy: TBD

16. TEMPO’s Potential Contributions
Aerosols (PM2.5) - focus on acute effect studies
Temporal resolution is great
Accuracy: should be comparable with MODIS?
Duration is OK for national scale studies
Spatial resolution is not great but OK
Not competitive for chronic studies
Long-term possibility
Retrieve aerosol composition info (AAI, AAOD, and more?)
Oversampling to get higher spatial res (1 km) with AAOD?

17. TEMPO’s Potential Contributions
O3 – focus on acute effect studies
Temporal resolution is great
Spatial coverage is great
Spatial resolution of 2.1 x 4.7 km2 is desired
Duration is OK for national scale studies
Challenge
Need to derive MDA8 and MDA1 values to be compatible with existing health study results
Long-term possibility
Sampling duration is not good for chronic studies but people will probably try it anyway

18. TEMPO’s Potential Contributions
NO2 – focus on acute effect studies
Temporal resolution is great
Spatial coverage is great
Sampling duration is OK for national scale studies
Spatial resolution is not good
Challenge
Need to derive MDA1 values
Need to develop models to improve spatial resolution
Long-term possibility
Sampling duration is not good for chronic studies but people will probably try it anyway
Further, airway responsiveness was increased following <1 to 6-hour 15 exposures to NO2 at concentrations in the range of 100 to 300 ppb, which are not much 16 higher than peak ambient concentrations.
The majority of the recent 1 evidence is from epidemiologic studies, which expand on findings for associations 2 between ambient NO2 and a broad array of respiratory effects from subclinical increases 3 in pulmonary inflammation to respiratory mortality, but particularly for effects related to 4 asthma exacerbation.
Given that motor vehicles are a major source, air concentrations of NO2 can be highly variable across neighborhoods (urban scale), depending on distance to roads. NO2 concentrations tend to decrease over a distance of 200−500 meters from the road and can be 30 to 100% higher within 10−20 meters of a road than at locations 20 farther away

19. TEMPO’s Potential Contributions
SO2 – focus on acute effect studies
Spatial coverage is great
Duration is OK for national scale studies
Temporal resolution is maybe OK
Spatial resolution is OK (away from sources)
Challenge
Need to derive daily and MDA1 values
Long-term possibility
Sampling duration is not good for chronic studies but people will probably try it anyway
Consistent associations between SO2 concentrations and asthma hospital admissions and emergency department visits that are generally unchanged in copollutant models have been demonstrated in epidemiologic studies using daily exposure metrics (24-hour average and 1-hour daily max), although the observed effects could be related to very short duration (5−10 minutes) peak exposures experienced during the day.

20. Personal Research Priority Ranking
Exposure models first!
convert TEMPO retrievals to ground concentrations!
Acute O3 > Chronic O3
Acute NO2 > Acute SO2
Acute PM2.5
Multi-pollutant acute studies
Chronic PM2.5, NO2, and SO2