Air Pollution as a Climate Forcing: A Workshop
Day 4 Presentations
Integrated Assessment of Human Health and Energy Option in Shanghai
Bingheng Chen and Haidong Kan
Department of Environmental Health, School of Public Health, Fudan University, China
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Shanghai, the biggest city in China, having a population of 6.3 million in urban districts and 13 million in Greater Shanghai (including urban and rural areas) has been under unprecedentedly rapid development in recent decades. The total area of Shanghai is 6,340 km2 with urban districts of 289 km2. The current study aimed at conducting a quantitative evaluation of ambient air quality and its health impacts in Shanghai, and a subsequent monetary valuation of the health impacts. The ambient air pollution level in Shanghai, in general, has been kept relatively stable along with rapid development in the last decade, with TSP and SO2 levels gradually decreasing while NOx level has been gradually increasing. This is due to the change in energy structure, polluting industries moving out from urban districts, increased areas of greenbelt, as well as other preventive and environmental friendly measures. This study emphasized the integrated assessment of health impacts related to energy options.
Approach. Quantitative risk assessment approach (hazard identification, exposure assessment, dose-response relationship/exposure-response relationship, risk characterization) plus percentage increase in mortality/morbidity per unit increase in air pollution levels is used as the basic approach in assessing health impacts from exposure to air pollutants. The estimated increments are based on epidemiological data from China or from other countries if relevant data are not available in China. Quantitative estimates of health effects expressed as avoidable deaths, hospital admissions, out-patient visits, emergency room visits, etc, from exposure to major air pollutants, which are related to change in energy structure and consumption, and hence to air pollution levels, are obtained.
Results. Retrospective comparison (1990-1999): By comparing the number of avoidable deaths and number of avoidable cases of respiratory and other diseases in 1990 with those in 1998 and in 1999, the benefits from change in energy structure and relocation of polluting industry in Shanghai is apparent. Compared with the 1990 air quality monitoring data, in 1999 there was a 53.3% decrease in annual TSP level (168 versus 360 mcg/m3), and a 53.7% decrease in the SO2 level (44 versus 95 mcg/m3), but a 52.3% increase in the NOx level (99 versus 65 mcg/m3). The total number of avoidable deaths in 1990 from exposure to TSP was estimated at 2,300 (low estimate) to 9,000 (high estimate). 450-1,200 avoidable deaths were due to chronic obstructive pulmonary diseases, 1,600 from cerebro-vascular diseases, 230-1,000 from cardiovascular diseases, 60-80 from pneumonia, and about 10 from cor pulmonale. The total number of avoidable deaths from exposure to SO2 was estimated at 450-2,400. 200-800 avoidable deaths were due to chronic obstructive pulmonary diseases, 50-240 from cardiovascular diseases, 840 avoidable deaths from cerebro-vascular diseases, and only 3 from cor pulmonale. There was a 78-80% reduction in avoidable deaths due to TSP exposure in 1999 compared with 1990. Since the annual mean level of SO2 was below the WHO/AQG guideline, no extra number of avoidable deaths from exposure to SO2 was expected.
Thanks to changes in energy policy and energy structure, relocation of industry, and change of business from the secondary industry (manufacturing) to the tertiary industry (services) for industrial entities that remain within the "inner ring", remarkable progress has been made in improving the ambient air quality in urban districts of Shanghai in recent years, resulting in fewer avoidable deaths and disease cases, and bringing about a better environment for people living in this area.
Prospective analysis: A quantitative estimate of the health effects (benefit/damage) associated with various energy scenarios in Shanghai in 2010 and 2020 was made. The year 2000 was selected as the base period in the analysis. In this assessment, Shanghai was divided into four kilometers by four kilometers grid cells, and the changes in population exposure level (exposure levels were provided by Chen Changhong et al, Shanghai Academy of Environmental Sciences) and incidence of adverse health effects in each cell were estimated. Total health effects associated with air pollution in Shanghai were equal to the sum of grid-specific changes. PM10 was selected as an indicator of "total air pollution" to estimate relevant health effects in this analysis.
Energy options could have significant impact on the health status for Shanghai residents. Compared to the base case (BC) scenario, implementation of various energy scenarios in Shanghai could prevent 647-5,472 and 1,265-11,130 PM10-related avoidable deaths (mid value) in 2010 and 2020, respectively. For the morbidity endpoints, alternative energy scenarios could prevent 1,315-11,100 new cases of chronic bronchitis, 377-3,286 cases of respiratory hospital admission, 260-2,260 cases of cardiovascular hospital admission, 27,080-237,900 internal medicine outpatient visits, 2,807-24,660 pediatrics outpatient visits, 49,490-414,200 cases of acute bronchitis, and 1,508-12,790 asthma attacks (mid values) in year 2010, respectively. In 2020, the numbers are expected to increase to 2,580-22,620 new cases of chronic bronchitis, 704-6,522 cases of respiratory hospital admission, 486-4,485 cases of cardiovascular hospital admissions, 49,850-468,600 internal medicine outpatient visits, 5,173-48,590 pediatrics outpatient visits, 98,520-850,800 cases of acute bronchitis, and 2,937-25,960 asthma attacks (mid values).
Economic valuation: An economic valuation of health outcomes associated with air pollution under various energy scenarios in Shanghai was conducted, which allows the performance of cost-benefit analysis of air pollution and health benefits, and also provides a basis for setting priorities for environment-related policies. The valuation of air pollution on mortality was assessed by using VOSL (value of a statistical life). The approach of WTP (willingness to pay) to avoid a statistical premature death was used in this assessment. The estimation of Shanghai VOSL relied on a contingent valuation study conducted in Chongqin, China. The effect of income on the VOSL was taken into account for the value transfer. The COI (cost of illness) approach was employed for valuing the endpoints of hospital admission and outpatient visits due to paucity of relevant WTP literature. Using a combination of WTP and COI approach, the total economical benefits in different scenarios with respect to BC scenario in Shanghai in 2010 and 2020 were estimated based on the health benefits gained.
Monetary valuation on the health benefits associated with different energy scenarios has revealed potentially high social benefits from these options. For different scenarios, the economic benefits could reach 113.4-950.6 and 327.4-2884.0 million US dollars (mean value) in 2010 and 2020, respectively. Among all the health outcomes, premature deaths dominate the value of the total benefits, accounting for around 90% of the number, chronic bronchitis also has an important contribution.
Conclusion. The health benefits from amelioration of ambient air quality due to change in energy structure, relocation of polluting industry, and adoption of other preventive and control measures in Shanghai were apparent, which were quantitatively estimated with a series of health outcomes ranging from morbidity to mortality. For different energy scenarios, the economic value of health benefits could reach 113.4-950.6 and 327.4-2884.0 US $ (mean value) in Shanghai in 2010 and 2020, respectively.