Local air quality management and health impacts of air pollution in Thailand

Air quality in urban areas of Chiang Mai Province, Thailand has seriously deteriorated as a consequence of population growth and urbanization and due to a lack of effective air quality management (AQM). As a result, respiratory diseases among Chiang Mai residents have increased in these affected areas. The health status and experiences of air pollution of both children and adults in Chiang Mai was assessed and improvements recommended to the developing AQM scheme. Air quality modelling, using ADMS-Urban was used to identify probable air polluted and control sites for further study. The polluted sites were found to be located along major roads in the city. However, ADMS-Urban was unable to predict air pollutant concentrations accurately because it could not cope with the very low wind speeds and complex topography of Chiang Mai. As a result, the utility of other air pollution modelling programmes should be investigated. The results of a questionnaire survey conducted with adults showed that urban respondents had a higher percentage of respiratory diseases than suburban respondents. However, later investigations were unable to establish a statistical linkage between air pollution concentrations and respiratory diseases. An ISAAC study was conducted among children attending schools located in the selected sites to assess the potential impacts of air pollution on health. The results showed that the prevalence of asthma was similar in all of the schools (approximately 5%) but that the prevalence of rhinitis (24.3% vs. 15.7%) and atopic dermatitis (12.5% vs. 7.2%) was higher in the urban schools which were considered to be more polluted. Logistic regression analysis identified other factors which may be involved in addition to pollution, including some components of the diet and contact with animals. In order to investigate the adequacy of the AQM system in Thailand, a comparative study was conducted between Hong Kong and Thailand. Both countries were investigated with respect to conformance to Good Urban Governance. The comparison showed that there are significant differences between the two countries and the AQM system in Hong Kong was more highly developed. For example, in contrast to the system in Hong Kong, it was found that there was insufficient involvement of the population in the development and implementation of AQM systems in Thailand. In order to better understand the reasons why the AQM system in Thailand is poor at both the provincial and local levels in Chiang Mai, prioritisation of AQM was assessed for major national environmental policies and plans; at the provincial level, fund allocations to development projects were reviewed; and at the sub-district level; a questionnaire survey was conducted among local government officials. It was concluded that AQM was not given sufficiently high priority in national plans and was generally ineffective and that, due to the non-specific nature of guidelines and frameworks in these plans, it was difficult for government organizations at the lower levels to establish AQM action plans for effective implementation. A range of appropriate measures to improve air quality in Chiang Mai were recommended. These included a more effective management of air pollution, an identified need for training and major changes in the transport system in the city.