CONTENTS -- Foreword -- Introduction -- Development of the update -- Scope of the update -- Key scientific issues in the development of the guidelines -- The updated guidelines and air quality management -- References -- Part 1 Application of air quality guidelines for policy development and risk reduction -- 1. Sources of air pollution -- Summary -- Introduction -- Primary pollutants -- Secondary pollutants -- References -- 2. Global ambient air pollution concentrations and trends -- Summary -- Assessment of air quality based on available monitoring data -- PM 10 or respirable particulate matter -- Ozone, a regional and global problem -- Sulfur dioxide, traditionally from the burning of fossil fuel -- Nitrogen dioxide, a problem related mainly to mobile sources -- Trends in air quality -- References -- 3. Human exposure to air pollution -- Summary -- Definition and concept of exposure -- Where does human exposure occur? -- Total exposure and time-activity patterns -- The influence of location on the relationship between sources and exposures -- Methods of exposure assessment -- Assessing long-term exposure to air pollution -- Critical time windows -- Relationship between personal exposure, indoor concentration and outdoor concentration -- Key factors determining the relationship between indoor and outdoor concentrations -- Overall strength of the relationship between personal (or indoor) and outdoor concentrations -- Population characteristics -- Impact of exposure measurement error -- Policy implications of exposure assessment -- References -- 4. Health effects of air pollution: an overview -- Summary -- Introduction -- What is an adverse effect of air pollution? -- Assessing the health effects of air pollution -- Choice of study design -- References -- 5. Determinants of susceptibility -- Summary -- Introduction -- Who are most affected?.

Chronic diseases as determinants of susceptibility -- Future considerations -- References -- 6. Environmental equity -- Summary -- Introduction to concepts of environmental equity and justice -- Policy contexts relevant to environmental equity -- Evidence of inequities in health effects of air pollution -- Evidence on the links between pollution sources and inequity -- Hot spots, episodes and cumulative impacts -- Future research and policy implications -- References -- 7. Health impact assessment -- Summary -- Introduction -- Previous studies -- Inputs for the analysis -- Benefits of conducting impact assessment -- A simple example of the methodology -- Uncertainties -- References -- 8. Application of guidelines in policy formulation -- Summary -- Introduction -- Setting air quality standards -- Implementation -- References -- 9. Indoor air quality -- Summary -- Background -- Characteristics of solid fuel smoke -- Indoor air pollutant levels in households using solid fuel: concentrations and exposures -- Health effects associated with exposure to solid fuel smoke -- Comparability of health impacts from indoor and outdoor air pollution -- Options for interventions -- Framework for air quality guidelines -- References -- Part 2 Risk assessment of selected pollutants -- 10. Particulate matter -- Introduction -- General description -- Exposures -- Mechanisms of toxicity -- Health effects -- Human exposure studies -- Evaluation -- Guidelines -- References -- 11. Ozone -- General description -- Route of exposure and toxicokinetics -- Summary of the pathogenetic mechanisms of ozone toxicity -- Health effects -- Guidelines -- References -- 12. Nitrogen dioxide -- General description -- Routes of exposure -- Kinetics and metabolism -- Health effects -- Evaluation of human health risks -- Guidelines -- References -- 13. Sulfur dioxide -- General description.

Health effects -- Evaluation -- Guidelines -- References -- Part 3 Annexes -- Annex 1 -- Pathogenesis of ozone-dependent injury -- Direct oxidation of cellular constituents -- Induction of respiratory and systemic inflammation -- Effects on immunity -- Factors defining susceptibility and tolerance to ozone -- References -- Annex 2 -- List of Working Group members present at the meeting in Bonn, Germany, 18-20 October 2005 -- List of authors and reviewers not present at the Working Group meeting.