Outdoor Air Pollution in Cambodia and Lao PDR
The effects on the populations of Cambodia and Lao PDR.
Outdoor air pollution is primarily an urban phenomenon, whose severity depends on the scale of polluting activity, its pollution intensity (or pollution per unit of output), and the characteristics of the urban air shed. Recent research has established that exposure to fine particulates (diameters of 10 microns (PM10) or less) is the main cause of pollution related respiratory disease. Until recently, little was known about fine-particulate pollution levels in Southeast Asian cities. During the past year, however, the World Health Organization and the World Bank have used a large international database to develop a prediction model for PM10 pollution, based on urban population, income, fuel use and local atmospheric characteristics (wind, rainfall, temperature, altitude, etc.). Combining this model with standard "dose-response" functions, we project PM10 concentrations and their impacts on health in urban areas of Cambodia and Lao PDR.
Aggregation of the results to the provincial level enables us to test for a poverty/environment nexus by assessing the spatial correlation between poverty and health damage from outdoor air pollution.
We would, of course, prefer to base our estimates on actual monitoring data. However, to our knowledge, previous environmental studies have not even attempted to estimate air pollution for cities in the region. We therefore offer these estimates as a suggestive benchmark for further research.
Using the WHO/World Bank model, we project PM10 pollution levels for urban areas in Cambodian cities. Estimated pollution levels are generally higher in cities located in Cambodia's population periphery. Using standard "doseresponse" models, we estimate the resulting loss of life and average loss of productive life- years for these cities and aggregated the results to the provincial level. The results suggest minimal correlation (0.14) between poverty population and deaths from air pollution, and a strongly negative correlation (-0.53) between poverty population and loss of productivity-adjusted life years. The latter reflects differences in provincial demographic composition, and suggests that provinces with relatively severe air pollution have populations that are, on average, significantly younger than the others. In these provinces, the loss of a life translates to the loss of a longer working life and, therefore, a greater productivity loss.
We conclude that outdoor air pollution is not a critical poverty/environment nexus issue in Cambodia. By South- and East-Asian standards, Cambodia has a relatively small PM10 problem because it is lightly- industrialized and its motor vehicle fleet is relatively small. The WHO/World Bank model estimates total national mortality from air pollution to be around 1,000 per year, with an associated annual cost that is less than 1% of gross national income.
Northern Laotian cities have generally-higher estimated air pollution than southern cities. We combine projected air pollution with dose-response models to obtain estimates of total mortality. The result is a high spatial correlation (0.68) between the poverty population and estimated deaths from air pollution. As in Cambodia, however, estimated mortality from air pollution is not high by Asian standards because Lao PDR is not heavily industrialized and the motor vehicle fleet is relatively small.