# Presentation: 300216

## Review of the Potential Health Impacts of Climate Change-Related Effects on Air Quality

**Kristie L. Ebi, Ph.D., MPH**
**Exponent**
_**[Kebi@exponent.com](mailto:Kebi@exponent.com)**_
**Climate Science in Support of Decision Making**
**14-16 November 2005**

## Outline

**Review of the impacts of poor air quality on human health**
**Air pollutants**
**Aeroallergens**
**Long-range transport of dust and other particles**
**Projections of the potential health impacts  of climate change-related effects on air quality**

## Climate Change Could Affect Air Quality

**Directly**
**Changes in chemical reaction rates**
**Boundary layer heights that affect vertical mixing of pollutants**
**Changes in synoptic air flow patterns**
**Indirectly**
**Changes in biogenic emissions**
**Increased frequency and intensity of drought, leading to more dust and other fine particles**

## Ground-Level Ozone

**Primary constituent of urban smog**
**Secondary pollutant formed through photochemical reactions involving NOx and VOCs in the presence of bright sunshine with high temperatures**
**Exposure to elevated concentrations associated with**
**Increased hospital admissions for pneumonia, chronic obstructive pulmonary disease, asthma, allergic rhinitis, other respiratory diseases**
**Increased mortality**
**Outdoor ozone concentrations, activity patterns, and housing characteristics are the primary determinants of ozone exposure**

## Trends in Ozone Concentrations

**Background concentrations have risen since pre-industrial times, and this trend is expected to continue over the next 50 years**
**Future concentrations depend on future emissions and weather patterns**
**Emissions depend on assumptions of population growth, economic development, and energy use**
**Fraction attributable to climate change is the portion that is the consequence of climate change on local temperature & UV**
**Assuming no change in the concentration of precursor emissions, the frequency of future ozone episodes will depend on the occurrence of the requisite meteorological conditions**

## Projections of Attributable Premature Mortality

| New York Metro Region
Knowlton et al. 2004 | Ozone-attributable deaths | Concentra-tion / response / function model | GISS GCM linked to RCM; A2 population | By 2050s under A2 climate, 4.5% increase in ozone deaths |
| --- | --- | --- | --- | --- |
| England and Wales
Anderson 2002 | Ozone exceedance days | Statistical model based on met factors | UKCIP scenarios
2000s, 2050s, 2080s | Large decreases in days with high particu-lates |

## Knowlton et al. 2004

***Knowlton et al. 2004***

## Other Air Pollutants

**Local conditions and emissions are of primary importance when determining human exposures**
**Transboundary transport also plays a significant role**
**Some locations, because of their general climate and topographical setting, are predisposed to poor air quality**
**Modeling results vary by region**
**US study projected an increase in the severity and duration of regional air pollution episodes in the Northeast and Midwest (Mickley et al. 2004)**
**UK study projected a large decrease in days with high particulate concentrations due to changes in meteorological conditions (UK Department of Health 2002)**

## Aeroallergens

**Strong evidence that observed higher temperatures are associated with an earlier onset of spring in the Northern Hemisphere, with an earlier onset of pollen production, particularly for late-winter and spring flowering plants**
**Trend is reversed at higher altitudes**
**It is not known whether the allergenic component of pollen also is changing**

## Long Range Transport

**Under certain conditions, aerosols, carbon monoxide, ozone, desert dust, mold spores, and pesticides may be transported over large distances and over timescales of typically 4-6 days**
**Dust can carry large concentrations of PM ****2.5 –**** ****10****, trace minerals, fungal spores, and bacteria**

## China Haze 10 January 2003

- NASA

**Windblown dust originating in desert regions of Africa, Mongolia, Central Asia, and China can affect air quality and population health over wide regions**
**Mortality, particularly from cardiovascular and respiratory diseases, is increased on days following a dust storm**

## Climate Change vs. Urban Air Pollution

- Climate change                Urban Air Pollution

**Burden of disease by region: Climate change and urban air pollution.  Disability Adjusted Life Year per million. World Health Report 2002.**

**Africa Region**
**South-East Asia Region**
**Eastern Mediterranean Region**
**Latin America and Caribbean Region**
**Western Pacific Region**
**Developed Countries**

**Millions of DALYs**

## Key Areas for Further Research: Air Pollutants

**Extensive, and growing, literature on the health impacts of air pollutants in developed countries**
**Fewer studies on the health impacts in developing countries, which experience higher concentrations of air pollutants**
**Better understanding is needed of how climate change might affect air pollution concentrations**
**Cloud cover particularly important for ozone formation**
**Additional modeling studies, incorporating relevant factors, is needed to assess whether climate change could add to future disease burdens**
**For both ozone and other air pollutants**

## Key Areas for Further Research

**Aeroallergens:**
**Need projections of the seasonal distribution of pollen under a changing climate**
**Need to understand whether the allergenic components of pollen will change with changing phenology**
**Long-range transport**
**Very little research has been conducted on health impacts**

## Thank you