Exposure to aerosol pollution and reported respiratory symptoms among segments of urban and rural populations in Sri Lanka

Abstract

(The Correct PDF for this article is now available)Health effects due to exposure to air pollution have become a growing concern as an ill-effect of rapid urbanization in several regions of Sri Lanka. Evidence suggests that exposure to particulate matter and other aerosols such as SO2 and NOx have increased in urbanized areas in Sri Lanka. But presently adequate evidence to show the association between health effects and air pollution is not available. In this ecological study, we present the micro-level picture of aerosol pollution obtained by using an interviewer administered questionnaire survey and comparing the results against exposure to aerosols. Secondary data were gathered on Sri Lankan health issues from the Ministry of Health to understand the most common causes of mortality and morbidity in the city. Symptoms and the medical diagnosis information were collected from randomly selected probability proportionate samples of five categories of street users (commuters in buses, three wheelers, outdoor venders, shop keepers and residents) in an urbanized area of Colombo and in a rural area of a peripheral district. Exposure levels were measured using passive air samplers in both locations. Moreover active sampling measurements of curbside levels of Total Suspended Particulate Matters (TSP), Sulfur Dioxide (SO2) and Nitrogen Dioxide (NO2) were collected in urbanized area. Aerosol exposure of urban and rural dwellers in all five categories, have shown significant differences in levels of SO2 (p = 0.001) and NO2 (p < 0.001). Three wheeler drivers and shop keepers showed no significant difference in SO2 levels in both locations (p = 0.045 and p = 0.113) while buses at both locations showed the highest NO2 and SO2 levels at both sites while houses had the lowest levels. Further analysis showed that the exposure levels of bus drivers significantly vary (SO2, F= 13.399, p = 0.001; NO2, F =52.283, p < 0.001) on the route characteristics (urban, urban to sub urban and rural). Urban street users had higher prevalence of cough (p < 0.001, OR = 3.43, CI = 2.29 - 5.15) and phlegm (p <0.001, OR = 2.19, CI = 2.29 - 5.15). Wheezing among city dwellers was 20.5% and among rural dwellers was 13.7% (p = 0.043, OR = 1.62, CI = 0.99 - 2.67).There was no significant difference in breathlessness over the different locations. The association might be overridden by localized risk factors such as difference in lifestyles among the urban and rural populations such as the higher number of people using wood as cooking fuel being in the rural site. Short- and long-term mitigation strategies are needed to reduce people's exposure to such air pollutants. The outcome of this study has been extended for necessary policy implications and mitigation guidelines by introducing recommendations of land use development in the city limits. DOI: 10.4038/besl.v7i2.1941 Built-Environment Sri Lanka Vol.7(2) 31-39