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Environmental Health Risks: The Health Effects of Ozone

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1 Environmental Health Risks: The Health Effects of Ozone
Healthy Carolinians Conference September 29, 2010 Susan Lyon Stone US EPA Office of Air Quality Planning and Standards

2 Review Process for Standards
Scientific studies on health and environmental effects EPA Integrated Science Assessment (ISA) EPA Risk/Exposure Assessment (REA) + Policy Assessment (PA) Scientific peer review of published studies Reviews by CASAC and the public Reviews by CASAC and the public Final Decision Public hearings and comments on proposals Proposed Decision Ozone final decision around the end October 2010

3 Human Lung Air conducting Trachea Bronchi Bronchioles Gas exchange
Respiratory bronchioles Alveoli

4 Ozone Irritates Airways
Symptoms Cough Sore or scratchy throat Pain with deep breath Fatigue Rapid onset Asthma symptoms - greater in people with asthma, also occur in people without asthma Ozone is a powerful oxidizing agent that irritates the airways, producing Symptoms Cough Sore or scratchy throat Pain when taking a deep breath – this may feel like a stitch in your side that doesn’t go away when you warm up – prevents you from taking a full deep breath Fatigue – inability to carry on with normal energy levels Symptoms come on quickly and are temporary, going away within a few hours Even though some of the symptoms are like the symptoms of asthma, they can occur in people who do not have asthma

5 Ozone Reduces Lung Function
FEV1, % CHANGE -20 Another effect that comes on quickly is the reduction in lung function – this occurs when the smooth muscles that surround the airways contract By lung function, we usually refer to the amount of air that can be exhaled after a full deep breath (FVC), and the speed at which the air can be exhaled (FEV1); ozone can reduce both of these measures of lung function Controlled human exposure study: Vertical axis the percent reduction in FEV1 and horizontal axis duration of exposure; more subject in this study, for simplicity we showing the results of the subjects with the smallest, largest and intermediate responses The first thing you notice magnitude of the reduction in lung function (about 50%) Medium reduction in lung function (>10-20% reduction FEV1) perceptible wheeze or chest tightness Large reduction in lung function (>20% FEV1) – obvious wheeze, marked chest tightness and breathing distress, brochodilator required to resolve symptoms Incapacitating reduction in lung function (>>20% FEV1, or less than 50% of predicted lung function), severe breathing distress, possible emergency treatment required if persistent The second thing you notice is that while one person is stopped in their tracks, another person had no change at all. Typical of these studies – variability in responsiveness to ozone – brought these people back into the lab One interesting thing is that we can’t predict who will be “unusually sensitive to ozone” – it’s not based on gender or any other known factor People with asthma have the same range of responsiveness to asthma -- we say that they are more sensitive because they often have poorer lung function to begin with -40 -60 BASELINE 2HR 4HR M-10

6 M-1c Ozone can cause inflammation
This is a schematic of an upper airway - BAL Ciliated epithelial cells, underlying tissue, blood vessel and RBC (red), WBC (blue), white layer on top epithelial lining fluid Ozone is a very reactive gas that primarily reacts with proteins and lipids in the ELF forming reactive oxygen species (e.g., lipid peroxides). Only in places where the epithelial lining fluid is thin does ozone damage the epithelium directly There is some evidence that taking antioxidants will mitigate the effects. Once the damage occurs white blood cells start to influx to the area and inflammation occurs We compare this inflammation to the inflammation you get on your skin with a sunburn Swelling, redness Doesn’t occur right away Cells that line the airways die, are sloughed off and replaced new ones In people with asthma this inflammation can lead to increased airway reactivity – real life Concern that repeated episodes of damage and healing may result in permanent structural changes in the lung “airway” resulting in reduced lung growth in children, and reduce quality of life in everyone M-1c

7 Ozone Causes Inflammation
Ozone reacts completely in surface layer - forms reactive oxygen molecules Increases permeability of cells that line airways Influx of white blood cells and proteins Damages cells that line the airways Effect is greater 24 hours after exposure Increases airway reactivity Concern about repeated exposures Cycles of injury and healing may lead to permanent structural changes - “airway remodeling” Children may experience slower lung growth Permanent changes may reduce the quality of life

8 Respiratory Hospital Admissions by Daily Maximum Ozone Level, Lagged One Day
(Burnett et al, 1994) 114 112 110 108 106 104 102 Respiratory Admissions This graphic is from an epidemiology study by Burnett from Environment Canada Vertical axis are respiratory hospital admissions; horizontal axis are ozone concentrations in ppm Shows that hospital admissions for all respiratory causes were higher following days when ozone levels are high Even though the total number of hospital admissions are small this illustrates the lack of a threshold for effects even at very low levels of ozone Ozone concentration (ppm) D-8a

9 California Children’s Health Study

10 CHS: Ozone and School Absences
20 ppb increase in O3 associated with an 83% increase in school absences for acute respiratory disease (Gilliland et al., 2001) Large economic impact of pollution-related school absences (Hall and Lurmann, 2003)

11 CHS: Ozone and New-onset Asthma
McConnell et al., 2002

12 Evidence from 2008 Review of Ozone Standard
Evidence of lung function decrements and symptoms at ppm in healthy people New information about physiological bases of increased sensitivity of people with asthma Larger decreases lung function Increased magnitude and duration airway responsiveness Increased inflammatory responses Different cellular responses Epidemiological studies show: Increased symptoms and medication use in asthmatic children School absences Emergency room visits and hospital admissions Premature mortality

13 Sensitive Groups for Ozone
People with lung disease Children Older adults People who are active outdoors

14 Descriptors Cautionary Statement Air Quality Index Good 0 – 50
No message Moderate 51 – 100 Unusually sensitive individuals Unhealthy for Sensitive Groups Identifiable groups at risk - different groups for different pollutants Unhealthy General public at risk; sensitive groups at greater risk Very Unhealthy General public at greater risk; sensitive groups at greatest risk

15 Dose = Concentration x Ventilation rate x Time
Air Quality Index Pollutant-specific health effects and cautionary statements address question “who will be affected” Dose = Concentration x Ventilation rate x Time C - be active outdoors when air quality is better V - take it easier when active outdoors T - spend less time being active outdoors Reduce these factors (C,V,T) to reduce dose Pay attention to symptoms People with asthma – follow asthma action plan Coaches – rotate players frequently People with heart disease – check with your doctor

16 Physical Activity and Health
Osteoporosis Prevention of Weight Gain Diabetes Mellitus Risk of “Disease” Strong Evidence • Lower risk of: – Early death – Coronary heart disease, stroke – High blood pressure, adverse lipid profile – Type 2 diabetes – Cancers: Colon and Breast • Prevention of weight gain • Weight loss (with reduction of caloric intake) • Prevention of falls • Depression, cognitive function (older adults) Moderate Evidence Functional ability (older adults) • Hip fracture, bone density, osteoporosis • Lung cancer and endometrial cancer • Weight maintenance after weight loss • Sleep quality • Evidence was insufficient for other conditions (e.g. anxiety disorders, prostate cancer) CHD Stroke Musculoskeletal Injury Functional Health Status Activity Source: HW Kohl, University of Texas School of Public Health 16

17 Effectiveness of the AQI
Effectiveness has been measured many ways Surveys: What people say Behavior Behavior and demographics (EPA, BRFSS) Activity diaries: What people do (RTI) Health studies: Changes in health outcomes Surveys Large proportion report awareness (50 -75%) Of those about 50% report taking action People of older age, fair or poor health status, and females more likely to reduce exposure (EPA Health and Aging Survey) Recommendation by healthcare provider much more likely to reduce exposure (Wen et al., BRFSS Survey) Odds ratio of changing behavior based on media reports = 2.16 (95% CI: 1.61, 2.90) Percent change in behavior based on alerts with professional advice = 50.7%; without professional advice = 14.2%

18 Determinants of Parents’ Ozone Forecast Monitoring
Parents of asthmatics more likely to report checking AQI forecast frequently More serious asthma = more frequent checking More children = less frequent checking White parent = less frequent checking Source: Carol Mansfield, RTI

19 Summary of results on time outdoors
Evidence that Air pollution sensitive asthmatics reduce time outdoors on code red days (based on daily diaries) 30+ minute reduction in time outdoors on Code Red day relative to non-Code Red day Source: Carol Mansfield, RTI

20 Air Pollution Sensitive vs. Not Air Pollution Sensitive Asthmatics
Source: Carol Mansfield, RTI

21 Health Studies Los Angeles study: Neidell and Kinney (2010)
Increase asthma hospitalizations per 10 ppb O3 - Neidell and Kinney (2010) Los Angeles study: Neidell and Kinney (2010) Asthma hospital admissions Control for air quality forecasts to account for avoidance behavior Accounting for behavior leads to significantly larger effects estimates; however there is a cost to behavior DFW: Carls U of MI dissertation Forecasts protective of health and alter relationships between asthma exacerbations and air quality Previous day O3 alerts were protective for high morbidity outcomes (hospital/ER); but not for the low morbidity outcomes (outpatient visits, medication use) All 5-19 ≥ 65 No control 0.017 0.016 0.022 With control 0.027 0.037 Difference 1.59** 2.31** 1.36* **P<0.01; *P<0.10 Change in asthma hospitalizations per 20 ppb O3 - Carls (2010) No control 7.0% Control 11.6%* Orange Alert - 14.1%* Red Alert -19.9% *P<0.05

22 Web cams 22

23 AQI Curriculum for Children and Students
Colorful lessons and games for children and students

24 Children’s Book

25 AQI Booklet

26 Ozone and Your Health


28 Downloadable Factsheets

29 Ozone Web Course for Health Care Providers

30 Medical Poster

31 Facebook: Twitter: Social Networking

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