Climate Change and Health Seminar Series: “Air pollution health effects under climate change: a complex interaction with various pathways”
November 15, 2022Information
Dr. Evi Samoli joined the Center on Climate Change and Health to discuss her work on air pollution and climate change.
Speaker:
Evi Samoli, Associate Professor of Epidemiology and Medical Statistics; Medical School of the National and Kapodistrian University of Athens (NKUA), Greece
October 10, 2022
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- 00:00<v Professor Chen>We're ready.</v>
- 00:01So let's get (indistinct), everybody.
- 00:04Thanks everyone, for (indistinct).
- 00:07It's our second (indistinct) series on (indistinct) today,
- 00:13and I'm very pleased today
- 00:17to be able to invite Dr. Evi Samoli for today's seminar.
- 00:22Dr. Samoli is Associate Professor
- 00:25of Epidemiology and Medical Statistics
- 00:28in the Medical School of the National and Kapodistrian,
- 00:32University of Athens in Greece.
- 00:35And Dr. Samoli's research interests
- 00:38focus on environmental epidemiology,
- 00:40especially the health effects
- 00:42of air pollution and climate change,
- 00:44and the development and application
- 00:47of statistical methods in related research.
- 00:50She has organized and participated
- 00:52in several statistical workshops
- 00:54and Greek and international conferences.
- 00:59She has been a reviewer
- 01:00and also a research committee member
- 01:02of the US Health Effects Institute,
- 01:05and also as for the WHO.
- 01:10She recently co-chaired this year's international conference
- 01:16for the International Society of Environmental Epidemiology.
- 01:21And her talk today will be
- 01:22Air Pollution Health Effects Under Climate Change:
- 01:25A Complex Interaction with Various Pathways.
- 01:29So without further ado, (indistinct).
- 01:33<v ->Thank you very much for the introduction, Professor Chen.</v>
- 01:37It's my pleasure to share some of the results
- 01:41with you and your class,
- 01:43and I would like to personally thank you
- 01:44for the invitation for this talk.
- 01:47Because I understand it's a rather diverse audience,
- 01:52I will focus my first slides
- 01:54on introducing the concept of air pollution,
- 01:57because as Professor Chen mentioned,
- 02:01my focus is on ambient air pollution,
- 02:04and what we know now of the health effects of air pollution,
- 02:07and then go deeper into how this interacts
- 02:10with the climate change health effects.
- 02:14Now to start with, the pollutant that we know
- 02:17has most effects on health is particulate matter
- 02:21with an aerodynamic diameter of 2.5 micrometers.
- 02:26To get you an idea of what particular matter PM 2.5 means,
- 02:31it's matter that is airborne in the air,
- 02:36and with small, so small as you can see from the graph here,
- 02:41that's smaller in fact than a red blood cell.
- 02:45So initially, we had investigated particulate matter
- 02:49that had a diameter of 10 micrometers, so was PM 10.
- 02:53But the most toxic effects of particulate matter
- 02:56are those associated with the smaller particles
- 02:59which are easier to penetrate into the lung
- 03:02from the respiratory tract
- 03:04and cause (indistinct) stress and inflammation.
- 03:08Now you must consider that
- 03:09because particulate matter is matter that is airborne,
- 03:14its composition changes according to its sources,
- 03:19and it also attracts different kind of chemical compounds
- 03:24depending on the atmosphere.
- 03:26So we have particles that are directly emitted from sources
- 03:30such as tailpipe exhaustion sources,
- 03:35or we have secondary particles formed in the atmosphere
- 03:38through chemical reactions.
- 03:41In this part of the slide,
- 03:43you can see the different figures,
- 03:47the different pictures of particulate matter
- 03:49that has different compositions.
- 03:51So for example, this is a biological source
- 03:55of particulate matter.
- 03:57The one next to it, I'm not sure if you can see my cursor,
- 04:01is my cursor visible while...
- 04:03<v ->Yes, we can see.</v> <v ->Excellent.</v>
- 04:05So this one is particulate matter
- 04:07that is emitted from tailpipes.
- 04:10It's soot particulate matter.
- 04:12This is from an unknown source, and this basically is dust.
- 04:19So not only the size of particulate matter differs,
- 04:23but also the composition differs according to sources.
- 04:26Of course, when we talk about ambient air pollution,
- 04:30apart from ambient particulate matter,
- 04:32we are exposed to a variety of gasses,
- 04:35of which the most common are nitrogen oxides
- 04:40and sulfur dioxide, carbon monoxide,
- 04:45and several hydrocarbons.
- 04:47Here in this slide,
- 04:49you can see the sources of particulate matter
- 04:52or gaseous pollutants from research in the UK,
- 04:57because you must understand
- 04:59that the main sources will differ
- 05:02according to the location, because the sources will differ.
- 05:06But in general,
- 05:07nitrogen oxides are mainly emitted from traffic,
- 05:11traffic related pollutants,
- 05:13and are emitted from tailpipe emissions,
- 05:17while particulate matter, depends on the sources,
- 05:20comes heavily from residential
- 05:22and small scale commercial combustion, as you see here.
- 05:26But also, it may be emitted from tailpipe,
- 05:29or non tailpipe sources, for example,
- 05:32they might be dust particles in the air
- 05:35that come also from the brakes
- 05:38and the tire contact of the car into the roads.
- 05:46From the gaseous pollutants,
- 05:47the one that has received most attention
- 05:49apart from nitrogen oxide,
- 05:51and the one that is most relevant
- 05:53with climate change is ozone.
- 05:56So you may be aware that ozone
- 05:59is in different strata of the atmosphere.
- 06:02When ozone is on the external atmosphere,
- 06:05what that is called the stratosphere,
- 06:07is the ozone that it's good for the environment,
- 06:10that protects, in fact,
- 06:12Earth from the sun's ultraviolet radiation.
- 06:15But when we talk about ozone in air pollution,
- 06:19we mean the ozone that is encountered in the troposphere,
- 06:24in the lower levels of the atmosphere.
- 06:27And this, in fact, is a secondary gaseous pollutant,
- 06:31because in order to form ozone in the troposphere,
- 06:36this is formed from secondary chemical reactions
- 06:39that require nitrogen oxides emitted from traffic sources
- 06:45in the presence of sunlight.
- 06:48That is why it is heavily dependent
- 06:50on climate change scenario,
- 06:52because as we expect that the heat will increase,
- 06:55the temperature will heat because of climate change,
- 06:59ozone levels are also expected to increase,
- 07:03and I will give a small presentation
- 07:05about the known health effects of these air pollutants.
- 07:10Now in general, air pollution health effects
- 07:12are very small, (indistinct) made very small relative risks
- 07:16compared to other risk factors for health.
- 07:19For example, we might estimate relative risks
- 07:24of the scale of 1.06.
- 07:28So it's a very small relative risk for human health,
- 07:31but if we consider the involuntary exposure
- 07:36of the whole population to air pollution,
- 07:39we understand why this is considered
- 07:42a major risk factor for human health.
- 07:46And this translates also to a large number
- 07:50of attributable deaths.
- 07:52So in general, in this pyramid,
- 07:54it's a classic pyramid portraying
- 07:56the effects of air pollution,
- 07:58where the majority of the population
- 08:00is in the bottom of the pyramid,
- 08:02and is expected to have only very minor symptoms.
- 08:08But as we go up to the pyramid,
- 08:12the severity of the effect increases,
- 08:16and the proportion of the population
- 08:18that is expected to experience
- 08:20these severe health effects is reduced.
- 08:23But nevertheless, because exactly the exposure is so wide,
- 08:28this is a considerable number of attributable cases,
- 08:32and that is why it's a very critical matter
- 08:35for public health.
- 08:38How do we estimate the health effects of air pollution?
- 08:42There are two kinds of ways to approach and investigate
- 08:45health effects of air pollution.
- 08:47One is short term health effects,
- 08:49meaning the health effects that are encountered
- 08:52after a few days, or at most,
- 08:56a month prior to the event that we're interested in.
- 09:00Or the long term health effects,
- 09:02meaning that the health effects that are attributed
- 09:06to cumulative exposure to air pollution, for example,
- 09:09to air pollution we're exposed to at our residence.
- 09:14And this may help, as it has been shown
- 09:18to increase the incidence of cancers,
- 09:21and particularly lung cancer.
- 09:23So there's those two ways of effects,
- 09:27either short or long-term effects.
- 09:29But nevertheless, as you may imagine,
- 09:32there's a continuing, continuing, excuse me,
- 09:35between short and long term health effects,
- 09:38that it's not completely understood.
- 09:42Short term health effects are very smaller
- 09:44compared to magnitude,
- 09:46compared to longer term health effects in general.
- 09:51You may be aware of the Global Burden of Disease project,
- 09:55that classifies risk factor for health globally
- 10:00in a periodic time periods.
- 10:03Air pollution is always classified
- 10:06on the 10 most important risk factors
- 10:09for health globally,
- 10:11either if this is accounted for in number of deaths,
- 10:16or disability adjusted years.
- 10:18In the latest classification
- 10:20of the Global Burden of Disease project,
- 10:23you may see that air pollution in terms of mortality
- 10:27was classified as the fourth risk factor,
- 10:30only below high blood pressure, smoking habits,
- 10:34and dietary habits as well.
- 10:38And it accounted for about
- 10:406.7 million deaths annually globally.
- 10:44Now these kinds of health effects are attributed,
- 10:47and this is what is estimated underneath these figures.
- 10:51These are health effects attributed to PM 2.5,
- 10:56as I introduced it earlier, and to ozone health effects.
- 11:00These are the two pollutants
- 11:02that we have the most consistent evidence on health effects.
- 11:07For PM 2.5, basically,
- 11:12this accounts for long term health effects,
- 11:15while for ozone, we are most certain
- 11:20about its short term lung effects,
- 11:22while the longer term health effects of ozone exposure
- 11:26are still under investigation.
- 11:29What kind of disease we are talking about
- 11:32when we are talking about air pollution health effects?
- 11:36You can see here from the State of Global Air,
- 11:39that I urge you to visit, is a site
- 11:42that it's been sustained by the Health Effects Institute,
- 11:45and has similar figures
- 11:48of the levels of air pollution globally,
- 11:50or the attributable number of deaths
- 11:53attributable to PM 2.5 exposure,
- 11:56ozone exposure, or even household indoors exposure.
- 12:01So we can see that we have about 40% of COPD deaths
- 12:09attributed to PM 2.5.
- 12:1220% about from diabetes deaths
- 12:16are attributed to air pollution.
- 12:1820% of ischemic heart disease,
- 12:20or lower respiratory infections.
- 12:23About 20% of lung cancer cases are also attributed
- 12:27to ambient air pollution, and also to neonatal deaths,
- 12:33it's a similar percentage, or stroke.
- 12:38Following these severe health effects
- 12:39for the general population
- 12:41and the importance in public health.
- 12:44WHO releases air quality guidelines regularly,
- 12:49and in the last month,
- 12:51it has released the more strict guidelines,
- 12:57requiring air pollutant levels for PM 2.5
- 13:02to be less than five micrograms per cubic meter.
- 13:05This is a mean year average.
- 13:09PM 10 is a bit higher, it's 15 micrograms,
- 13:13the limit suggested.
- 13:14For ozone, you can see it's 60 micrograms per cubic meter.
- 13:19Ozone usually is measured in the US in parts per billion.
- 13:23So you may see the units in PPB.
- 13:27And the nitrogen dioxide is about
- 13:3010 micrograms per cubic meter as a annual average.
- 13:3524 daily averages are always a bit larger.
- 13:43Now how do this compare to the existing levels
- 13:47of air pollutants?
- 13:48I may assure you that both for US
- 13:51and the large majority of European countries,
- 13:56these are lower than the existing levels of air pollution,
- 14:01considering the year averages.
- 14:04The WHO air guidelines
- 14:07are not legislative binding for the countries.
- 14:13They're based on protecting public health,
- 14:16and then the area specific authorities
- 14:22release their own guidelines,
- 14:24taking into account not only the interest of public health
- 14:29and how this is reflected in the WHO guidelines,
- 14:32but also, as you may imagine, other aspects
- 14:35such as the cost benefit fractions,
- 14:38and how would this impact the economy
- 14:42in order to lower the levels in terms of productivity,
- 14:45industry, and so on, and so on.
- 14:48So here, in this slide, you will see the limit values
- 14:53that are currently existing,
- 14:57both in the European Commission on the left,
- 15:00and UN's on the right that you can see.
- 15:04The levels are higher than those
- 15:07that are proposed by the WHO.
- 15:10For example, for PM 2.5, you can see here,
- 15:14depending on the source, that EPA suggested limit values
- 15:19are very much higher
- 15:21than the five micrograms per cubic meter
- 15:24proposed by WHO, while for the same pollutant and metric
- 15:33in Europe, we have even larger limit values.
- 15:37These are the legislative binding limit values
- 15:41for the state members.
- 15:42So in Europe, for example, if we exceed this kind of limit,
- 15:47we are under fine to the European Commission.
- 15:53And nevertheless, it's clear that this is not a measure
- 15:57that protects public health,
- 15:58and it's a big pressure nowadays to lower the limits,
- 16:02both in US and the European Union.
- 16:06So coming into the interplay
- 16:08with climate change health effects.
- 16:11We know that the climate change health effects
- 16:15can be either direct or indirect.
- 16:18For example, we have direct health effects
- 16:21due to climate change extreme events,
- 16:23such as heat strokes under heat waves,
- 16:27or we may have fatalities in wildfires
- 16:32and similar extreme events.
- 16:34But we also have indirect health effects
- 16:36attributed to climate change,
- 16:39because climate change impacts also
- 16:42the quality of the air,
- 16:45so it worsens the levels of air pollutants.
- 16:48Hence, we have this indirect effect
- 16:52from increasing the health effects of air pollution
- 16:56that I mentioned earlier.
- 16:59I will show in the later slides
- 17:02that this is a much more complex interaction
- 17:06between climate change events and air pollutants.
- 17:09It also has indirect health effects,
- 17:12because climate change impacts also public health services.
- 17:18So the public health sector is not ready
- 17:22to accommodate the extra events
- 17:25attributed to climate change extreme events,
- 17:27but also to the entire effect that follow
- 17:31climate change events.
- 17:34This comes from a report in the European Commission
- 17:38that somehow schematically illustrates what you may know,
- 17:42that temperature has effects on human health.
- 17:45We know that, for example,
- 17:48mortality occurs in low temperatures or in high temperature.
- 17:52The shape between temperature levels and health
- 17:56is a parabola, a U shape,
- 17:59where we see increasing events in the very low temperatures,
- 18:02as you may imagine, or the very high temperatures.
- 18:05So temperature has a direct effect on human health.
- 18:10And in fact, the temperature effects on health
- 18:14are more strong in magnitude
- 18:16than the effects of air pollution that I mentioned earlier.
- 18:21As you may see from the report of the European Commission,
- 18:25there's a geographical variability
- 18:28in the health effects of temperature,
- 18:31and generally of climate change.
- 18:34We have more severe effects in hotter climates,
- 18:38such as the southern Europe
- 18:41compared to the northern European countries.
- 18:43And we have also, not only geographical probability,
- 18:46but we have a (indistinct) effect
- 18:48depending on the subpopulation groups we are interested in.
- 18:52So people that are usually more sensitive
- 18:57to meteorological and air pollution health effects
- 19:00are children, pregnant women,
- 19:03and elderly citizens, or people with preexisting diseases.
- 19:12Why now climate change has a more complex pathway
- 19:18to health through air pollution?
- 19:20Because air pollution emissions also are a contributor
- 19:26to climate change events.
- 19:30So emissions increase temperature,
- 19:34that constitutes part of climate change,
- 19:37and this, in fact, the increase in temperature,
- 19:40as I mentioned in the beginning of the talk,
- 19:43is necessary to produce more ozone,
- 19:45that is also known to have adverse health effects
- 19:49to human health.
- 19:51There are also interactions
- 19:53between temperature and air pollution,
- 19:55meaning that we have higher effects of temperature
- 19:58in more polluted areas,
- 20:00or we have higher effects of air pollution in warmer areas.
- 20:05This still now have traditionally been studied separately,
- 20:09but because of the complex interplay between climate change,
- 20:14and particularly temperature levels and air pollution,
- 20:18in the recent years,
- 20:20this have received increasing attention,
- 20:23and more publications are coming up,
- 20:25and I will just go through some main publications
- 20:28on the topic in the later slides.
- 20:32Apart from this interplay
- 20:35between temperature and air pollution,
- 20:39we know that climate change
- 20:41increases the occurrence of wildfires.
- 20:45Wildfires are a main source of emission
- 20:48of particulate matter in the air.
- 20:51For example, you may recall
- 20:52the very intense wildfires that burnt over California,
- 20:57I think this was two years ago.
- 20:59The smoke reached all the way
- 21:02up to the east coast of the US.
- 21:04So we have the source of wildfires
- 21:07that not only impacts the location where wildfire occurs,
- 21:11but also depending on the wind direction and the atmosphere,
- 21:16atmospheric reaction, may also impact air quality levels
- 21:21in further distances.
- 21:25Further up to that,
- 21:27climate change is expected to increase drought,
- 21:31and also the frequency of desert dust episodes.
- 21:35I told you in the beginning
- 21:37that one source of particulate matter
- 21:39in ambient air is dust.
- 21:41So we have occurrences of desert dust transport,
- 21:44for example, in Greece, and in the southern of Europe,
- 21:48we have desert dust transport,
- 21:51traditionally during spring or early summer,
- 21:54from the Sahara area.
- 21:56Depending on meteorological conditions,
- 21:59Sahara area has been shown
- 22:01also to reach the east coast of US sometimes.
- 22:03So these kinds of desert dust episodes
- 22:06are expected to increase both in frequency and duration.
- 22:12Apart from that, also the fact that climate change
- 22:16increases drought,
- 22:18we can understand that this also will increase
- 22:21suspended particles from dust sources.
- 22:28This publication is a nice figure,
- 22:32also graphically showing this direct and indirect effects
- 22:37between climate change and, in fact,
- 22:40the focus of this publication was cardiovascular mortality,
- 22:46because you may know that cardiovascular mortality
- 22:50typically consists about 30 to 40% of total mortality.
- 22:56So we can see that from climate change
- 23:00can have a direct effect to cardiovascular...
- 23:03Climate change leads to extreme temperature.
- 23:07Extreme temperature may cause cardiovascular inflammation,
- 23:12that will lead to cardiovascular mortality
- 23:16through direct effect,
- 23:18but also through increases in the ozone levels,
- 23:22that we know has impacts on cardiovascular mortality,
- 23:26has an indirect weight towards there.
- 23:30As mentioned earlier, also,
- 23:32the wildfires will increase due to climate change,
- 23:36and wildfires basically are causing increases
- 23:42in the levels of nitrogen dioxide and particulate matter,
- 23:47and in a specific chemical composition of particulate matter
- 23:52that is black carbon
- 23:53because when solid fuel produces black carbon,
- 23:58which is one of the constituents,
- 24:01possible constituents of ambient particulate matter,
- 24:04that from research until now
- 24:06has been shown to be one of the most toxic components
- 24:10of particulate matter.
- 24:11So wildfire is expected to affect cardiovascular mortality,
- 24:17again through the same biological pathway,
- 24:21either by increasing nitrogen dioxide particulate matter,
- 24:26and when nitrogen dioxide increases,
- 24:28because it's a necessary
- 24:30ingredient for the formation of stratospheric ozone,
- 24:33also ozone will increase.
- 24:38This is a very nice graph from a current European project
- 24:43we are running.
- 24:45Professor Chen is aware of this,
- 24:47and this has been a graphical display exactly
- 24:53of the impact of climate change on air pollution
- 24:56and related health effects,
- 24:58in order to communicate this to the general public.
- 25:03So you can see, again, that the title, I think,
- 25:06is very good for commercial and scientific reasons.
- 25:10We breathe climate change.
- 25:12So the impact on cardiovascular mortality
- 25:15comes from heat waves,
- 25:17tropospheric or ground level ozone particulate matter,
- 25:20wildfires, and then we have the health impacts,
- 25:24that especially in Europe, it has been estimated
- 25:28that air pollution may cause up to 800,000 premature deaths.
- 25:37Oops, I'm sorry.
- 25:40A few words, what we mean
- 25:44when we talk about ozone health effects.
- 25:47This is the results of the global study
- 25:50on the short term exposure to ozone,
- 25:53and all cause mortality.
- 25:56In the figure in the left, you may see the countries
- 25:59that provided data to the specific study,
- 26:05and here you can see per country,
- 26:06the number of cities that contributed to data.
- 26:10We had 188 cities from US that contributed data.
- 26:16You can see that US contributes
- 26:18a lot of ozone and mortality data,
- 26:20and also a lot of European cities
- 26:23contributed relevant data,
- 26:25and we had fewer countries in the Eastern Asia,
- 26:29a few in Asia and in Africa, and some in Australia.
- 26:34The figure shows the different levels of ozone,
- 26:38and here, you can see what the estimates,
- 26:43the relative risks in total mortality
- 26:46for a 10 micrograms per cubic meter increase in ozone.
- 26:51So this is short term health effects of ozone.
- 26:55It's the previous day ozone,
- 26:58and how this will increase the next day
- 27:02total mortality in the cities.
- 27:04And you can see, for example, that in the United States,
- 27:08the 10 micrograms increase in ozone
- 27:11is associated with about 0.2% increase
- 27:16in daily number of deaths.
- 27:170.2% increase is a small increase in terms of magnitude.
- 27:24But when we translate this into number of deaths,
- 27:28you can see that this is a large number of deaths.
- 27:32For example, if ozone exceeds the guideline from WHO,
- 27:39at that point was 100 micrograms per cubic meter in the US,
- 27:43this was attributed to about 200 annual excess deaths
- 27:49attributed to ozone short term exposure.
- 27:52And this, in fact, was a 0.4% increase in total mortality.
- 27:57So about, rather, a large percent of total mortality
- 28:05could be attributed to ozone exposure.
- 28:09You can also see that
- 28:10depending on the area of the world analyzed,
- 28:13the magnitude of effects differed.
- 28:16Okay, for example, in Athens, that's a smaller country,
- 28:22sorry, smaller city, because we only contributed one city
- 28:26to the analysis, compared to Los Angeles, for example,
- 28:31but is the estimate here, we have fewer number of deaths,
- 28:35because we have a smaller population.
- 28:40Especially for USA, it has been estimated
- 28:43that one to four degrees Celsius increase
- 28:47in mean daily temperature will lead to an increase
- 28:51of ozone levels by one to five parts per billion.
- 28:56This is about 10 micrograms per cubic meter increase,
- 29:01and this is expected to account
- 29:03for tens of thousands of hospitalizations
- 29:06and deaths annually by 2030.
- 29:10It has also been an estimate,
- 29:14because you may recall that in 2003,
- 29:17we had a major heat wave in Europe,
- 29:21when a lot of excess deaths were attributed exactly
- 29:25to the effect of this heat wave.
- 29:28There was a recent study indicating
- 29:30that about half of these effects of these deaths
- 29:34could be attributed to the ozone exposure
- 29:37that increased exactly because of this extreme heat days.
- 29:45This is one of the first studies to address,
- 29:50is a study by Professor Chen, in fact,
- 29:52and it's one of the first studies
- 29:54to simultaneously assess the interaction,
- 29:57the interplay between temperature levels
- 30:00and air pollution levels,
- 30:02and their impact on the daily mortality.
- 30:04It was an analysis that incorporated data from,
- 30:10you can see, eight different areas in Europe,
- 30:14spanning from Finland to Greece.
- 30:17So we had cities from northern Europe,
- 30:21central Europe, and southern Europe,
- 30:24and the table below shows the results,
- 30:28how the air pollution health effects differ
- 30:32according to different levels of air pollution.
- 30:35Just to briefly mention,
- 30:37we have the previous day ozone health effects,
- 30:41the previous day PM 10 health effects,
- 30:44the previous day PM 2.5 health effects,
- 30:47and PNC are even smaller particles.
- 30:51It's a metric to study ultra fine particles,
- 30:55that are particles that have a diameter
- 30:59even smaller than 0.1 micrometer.
- 31:06So if you see a bit closer,
- 31:08the percent increase of mortality
- 31:11attributed to each pollutant
- 31:14depending on the levels of temperature,
- 31:17we can see steadily that there is a trend
- 31:20that we have higher effects for all air pollution,
- 31:24for all air pollutants studied
- 31:26when air temperature levels are higher.
- 31:30And the same goes for cardiovascular deaths.
- 31:35Following this study by Professor Chen,
- 31:38there have been many other studies
- 31:40following the same rationale,
- 31:41and investigating this interaction
- 31:43between temperature and air pollutants.
- 31:45And this is a nice review of several studies
- 31:49across the globe that have tried to assess
- 31:54the interaction between particles and temperature,
- 31:58and try to estimate future attributable events
- 32:02depending on emission scenarios,
- 32:05both for air pollution and future climatic scenarios.
- 32:11I see that we are running a bit out of time,
- 32:14so I will go very quickly through this.
- 32:17We have the slides,
- 32:19and you can follow up the references if needed,
- 32:22but depending on the area,
- 32:25you can see that we have different air pollutants
- 32:28that have been assessed.
- 32:30The majority of the studies assess the effects of ozone,
- 32:34and in all of them that assess the effects of ozone
- 32:37under different scenarios,
- 32:39assessed an increase in attributable cases
- 32:41to ozone exposure.
- 32:43Attributable cases to particle exposure
- 32:46depending on emissions of air pollution
- 32:48and climate change scenarios
- 32:50differed according to the study.
- 32:53We had peaks of particulate matter related deaths,
- 32:57then deaths stabilized,
- 32:58or depending on the scenario,
- 33:00this was not such a consistent pattern as was for ozone.
- 33:05In any case, the authors urge
- 33:08that future scenarios to try to account
- 33:11for both changes in emissions,
- 33:15because we have transitioned, for example,
- 33:19from solid fuel to the electric fleet for traffic,
- 33:24but also to different measures
- 33:26that will account for different emissions
- 33:30that will change future climate change scenarios
- 33:34and associated temperature levels.
- 33:37This is a systematic review and meta-analysis
- 33:40trying to assess the evidence
- 33:42on the combined effects between air pollution,
- 33:45temperature, and pollen exposure.
- 33:47I will not go very much in depth,
- 33:49but this table shows a summary of the results
- 33:55that started all three exposures together,
- 33:57because climate change impact,
- 33:59my talk is focused on human health,
- 34:02but of course, climate change has impact on agriculture,
- 34:07and this is expected also to increase
- 34:11certain levels of pollen, that is also, as we know,
- 34:14associated with respiratory effects.
- 34:17So the authors only managed to appraise six studies
- 34:21that assessed the three exposures altogether,
- 34:24and depending on certain criteria
- 34:27of consistency of the evidence
- 34:30of the cumulative effect of these three exposures,
- 34:33concluded that overall, there was low quality
- 34:37in the evidence to support interactive effects
- 34:41of all air pollutants,
- 34:44but there was some limited evidence for indications
- 34:47of interaction effects.
- 34:50They figured that there was a much larger literature
- 34:55that had assessed both heat effects
- 34:58and air pollution simultaneously,
- 35:00and they managed to gather 39 studies
- 35:04that assess the interactive effects on both.
- 35:07And the conclusion of this systematical use
- 35:11is that, in fact, there was a moderate quality of evidence
- 35:15that those response relationships in a number of studies
- 35:22was moderate, but there was sufficient evidence
- 35:26that there was synergistic effects
- 35:28between heat and air pollution exposures,
- 35:31specifically for ozone and particulate matter.
- 35:36This is a nice review on the climate change impact
- 35:40on human health and agricultural effects, productivity,
- 35:47and of course, the different impacts are studied
- 35:50according to different designs,
- 35:52and you can see that we have mainly, of course,
- 35:55observational studies assessing the impact
- 35:59on human health, and mostly,
- 36:02when we talk about temperature and air pollution,
- 36:05I forgot to point out we are focusing on short term,
- 36:09because we know that temperature has a short term
- 36:12of human health, and in fact,
- 36:15high warm temperature have a effect on health,
- 36:19meaning have increasing hospitalizations
- 36:22due to cardiovascular or respiratory causes,
- 36:25or increase in cardiorespiratory mortality
- 36:28that spans from the same day
- 36:31up to three days later than the events,
- 36:34while the effect of the cold temperature
- 36:36is expected to have a much longer impact.
- 36:40So we may observe hospitalization and mortality counts
- 36:44associated with cold effects even following
- 36:48two weeks after the cold effect, the cold level observed.
- 36:54So in any case, when we talk about interaction
- 36:58between temperature and air pollution,
- 37:01we are focusing on short term health effects of both.
- 37:05And in this review, also, it pointed out several designs,
- 37:10and how this was studied both on human health
- 37:12and agricultural impacts,
- 37:14and there was this nice figure
- 37:17showing that temperature does modify
- 37:20air pollution impacts on health
- 37:22depending on the area, the pollutant studied,
- 37:27or the methodological parameters studied,
- 37:31and that contributed to climate change effect,
- 37:34and also the vice versa,
- 37:35that air pollution also modified temperature health effects.
- 37:43I prefer to briefly show you some results.
- 37:50This is unpublished work, sorry about this.
- 37:54This is unpublished work for, again, a global study.
- 37:58You can see that this study includes about 500 cities
- 38:02spanning across the globe from 32 studies
- 38:04that contributed data on air pollution and temperature,
- 38:09and in fact, present results for the interaction effect
- 38:13between temperature and air pollution levels,
- 38:16the short term exposures, and the impact on total mortality.
- 38:21You can see in the graph again
- 38:22that the majority of the cities contributing data
- 38:25come from US and Europe,
- 38:28and the difference at the top
- 38:30is the different levels of average temperature,
- 38:33and lower is the different levels of ozone, for example.
- 38:38To graphically quickly show you the results,
- 38:41these are the results from North, Central,
- 38:44and South America.
- 38:46So we have the PM 2.5,
- 38:48let's focus on the main central figure.
- 38:52It's PM 2.5 effects,
- 38:54or total mortality by levels of pollutant.
- 38:58So you can see again a steady trend,
- 39:01both for Canada, for example, and US,
- 39:04although this may not be statistically different
- 39:09between them.
- 39:10As temperature levels increased,
- 39:12the effect of PM 2.5 on mortality increases.
- 39:17This is not the pattern that is observed in Mexico
- 39:20or other areas of Latin America,
- 39:25but of course, you may consider that the number of cities
- 39:28contributing data differs by the country shown here.
- 39:33The same patterns, pretty much,
- 39:36was observed in the majority of the European cities.
- 39:40You can see here for PM 2.5 in Northern Europe,
- 39:44we have increasing terms in Norway,
- 39:49but not a consistent pattern for other countries.
- 39:52There was a increasing trend
- 39:55also for (indistinct) particles, and the levels,
- 40:00the effect of ozone depending on temperature levels
- 40:04did not seem to vary in the European cities.
- 40:11To give you an idea in numbers,
- 40:14these are the overall global estimates
- 40:18of the health effects of the pollutants
- 40:20depending on the level of air pollution.
- 40:23So globally, we may see increasing effects,
- 40:26either of PM 10, PM 2.5, or ozone effects
- 40:31on total mortality.
- 40:33Of course, because these are global estimates
- 40:35of the air pollution health effects,
- 40:38there is large (indistinct) in this kind of meta-analysis.
- 40:43As I mentioned earlier, indirect pathway
- 40:45between climate change and air pollution health effects
- 40:49comes from wildfires,
- 40:51and here is one study we had been doing
- 40:56about 20 years ago that studied the impact
- 40:59of forest fires on mortality,
- 41:01and how this could be associated from particulate matter.
- 41:05This is a dot diagram trying to figure out the pathway
- 41:11that this may have affected health.
- 41:13So we may have direct effect,
- 41:16direct death as an effect of forest fire,
- 41:19or we may have an indirect death
- 41:22through increases in particulate matter levels,
- 41:26or even through increases in temperature,
- 41:28because locally, the temperature levels also increase
- 41:33due to wildfire.
- 41:34So this may affect our health outcomes in multiple pathways.
- 41:40This figure shows the severity and occurrence
- 41:43of forest fires in the Southern Europe from 2003 to 2011.
- 41:49Of course, there was variability depending on the country,
- 41:53but in general, we saw that there was not much difference
- 42:00on the effects of particles depending on forest fire days
- 42:05or non forest fire days.
- 42:09On smoke free days, for example,
- 42:11there was a 0.5% increase in total mortality,
- 42:17and on wildfire affected days,
- 42:20the increase in mortality was almost double,
- 42:23but it was not statistically significant,
- 42:26and it was a very wide (indistinct).
- 42:29But that's why I mentioned that,
- 42:31although the results may not be
- 42:33statistically significantly different between them,
- 42:37because we have much fewer count of wildfire affected days,
- 42:43we can see that in most of the cases,
- 42:46the impact is greater in wildfire affected days.
- 42:51I mentioned briefly
- 42:52that what solid fuel emits is black carbon,
- 42:56and I mentioned that black carbon
- 42:58is one of the most toxic components
- 43:00of ambient particulate matter.
- 43:03Black carbon health effects
- 43:05have been increasingly been studied.
- 43:07This is again from the same consortium that I showed you
- 43:11the paper before, from forest fires,
- 43:13that we assessed the effects of black carbon on mortality.
- 43:19And we can see that it had high health effects,
- 43:23either on the same day of exposure,
- 43:25or up to an average of three days before the events,
- 43:30both in Athens and Barcelona.
- 43:32And the effects of black carbon were much higher
- 43:34than the ones that usually are observed and attributed
- 43:39to particulate matter.
- 43:42This is another study on wildfire sourced PM 2.5,
- 43:49also coming from the same consortium
- 43:52studying short term health effects
- 43:55of air pollutants and temperature effects.
- 43:57And this study focused exactly on the health effects
- 44:01from PM 2.5 that was emitted from wildfire.
- 44:06And you can see again, the figure,
- 44:08the number of city that contributed data, sorry,
- 44:14and the level of wildfire related PM 2.5 by city.
- 44:21They assessed the effect of wildfire PM 2.5,
- 44:26either on the same day, or up to six days before,
- 44:29or the red...
- 44:33The red point on the figure on the left
- 44:35stands for the three days moving average
- 44:38of the exposure to wildfire related PM 2.5.
- 44:43So in all cases, we see very high effects
- 44:47up to three days after the exposure,
- 44:50or on the average of the same
- 44:53and two days prior to the event.
- 44:56Particularly for US, there was a 0.3% increase
- 45:01in total mortality associated with PM 2.5
- 45:05that could be attributed to wildfires.
- 45:09And this was the same percent increase
- 45:12attributed also for cardiovascular or respiratory mortality.
- 45:15Again, the magnitude on the effects
- 45:18depending on the location, as you may expect, differs.
- 45:24I also mentioned briefly that we expect an increase
- 45:27in the frequency duration of desert dust episodes,
- 45:31and we know also that desert dust
- 45:34may have impacts on health, and here is again a paper
- 45:41investigating the impact of desert dust
- 45:47on daily mortality in southern Europe.
- 45:51And you can see,
- 45:52because particles from desert dust are of larger diameter,
- 45:58we assessed here the health effects of PM 10,
- 46:01that are larger, as I mentioned in the beginning,
- 46:03compared to PM 2.5, and whether this could be attributed
- 46:08to non desert dust sources,
- 46:10or desert sources, excuse me.
- 46:14So in total, for example, for all cause mortality,
- 46:18an increase in PM 10 was associated
- 46:21with a 0.5% increase in total mortality.
- 46:25This was a bit higher, 0.55, for non desert PM 10,
- 46:32and PM 10 originating from desert dust
- 46:38had even higher effect on total mortality,
- 46:42and pattern was pretty much the same
- 46:44when we assessed cardiovascular mortality,
- 46:47respiratory mortality,
- 46:48and also there was an impact on hospital admissions.
- 46:53Just to close, and apologies for taking all the time.
- 46:57We had a major event in Athens last year
- 47:00that you may not be aware of,
- 47:03but for our twisted mind as scientists was very intriguing,
- 47:09because we have a very intense heat wave
- 47:12that lasted more than three weeks,
- 47:16and after two weeks of heatwave,
- 47:18also a major wildfire started
- 47:22in the northern suburbs of Athens.
- 47:24So we are in the process of studying this
- 47:29on mortality in the general population of Athens.
- 47:32The graph shows the excess number of deaths,
- 47:36and you can see the counts in daily mean temperature
- 47:42in the previous years, compared to the period
- 47:47that the heat wave and the desert
- 47:49and the wildfire started in Athens,
- 47:53and also the average number of deaths in previous years,
- 47:58and the excess numbers of deaths during this episode,
- 48:01that we can see higher increases, of course,
- 48:03in temperature and excess deaths.
- 48:05And briefly, some very premature results.
- 48:09When we try to associate the increase on mortality,
- 48:13on daily mortality
- 48:14attributed to this very intense heat wave,
- 48:17this accounted for about 20% increase.
- 48:21This is a huge increase.
- 48:22If we consider, for example, that high temperature levels
- 48:28account for about four to 5% increase in daily mortality,
- 48:3320% increase in daily mortality due to a heat wave
- 48:36is a very severe public health issue.
- 48:40And this even reached 70% increase in daily mortality
- 48:44when this intense heat wave
- 48:46was combined with a wildfire that lasted about a week
- 48:51in the outskirts of the city.
- 48:54So to conclude, and thank you for your attention,
- 48:58there seems to be synergistic and interactive effects
- 49:01between climate change variables,
- 49:03such as temperature and air pollution.
- 49:06There is heterogeneity on the effects,
- 49:08depending on the location we are studying,
- 49:11but this may be also attributed
- 49:13to a large variety of factors, also socioeconomic factors,
- 49:17the percent of aging of the population,
- 49:21and other demographic characteristics.
- 49:24There is a call for further research interactions
- 49:27between parameters of air pollution
- 49:29and climate change events,
- 49:31but also on the assessment of the cumulative effects
- 49:34of all these environmental factors.
- 49:38And there's also a need
- 49:39to address more complex future scenarios,
- 49:42accounting for reduction on tailpipe emissions
- 49:46due to the electrification of the fleet,
- 49:50as I mentioned earlier.
- 49:52But this is also expected to account for an increase
- 49:55in non tailpipe emissions, due to tire wear and brake wear.
- 50:01And we need to push through policy decisions
- 50:06to develop solutions that will effectively tackle
- 50:09both climate change and air pollution levels,
- 50:13because these seem to be
- 50:19undividedly interchanged between them.
- 50:22So thank you very much for your attention,
- 50:25and I would particularly like to thank my team
- 50:28in the University of Athens,
- 50:29and also the consortium of the EXHAUSTION research program
- 50:34at (indistinct) in Europe.
- 50:36And I will be happy to discuss any questions,
- 50:39either today, or in person in about two weeks time.
- 50:46<v Professor Chen>Thank you.</v>