Health Risks Associated with Ambient Ozone and Temperature in Metropolitans in Taiwan
Date Issued
2011
Date
2011
Author(s)
Lin, Yu-Kai
Abstract
Ambient ozone and temperature have been predicted to increase in next decades; consequently the health risks associated with ozone and temperature deserve study. This study aims to: (1) analyze the temporal and spatial patterns for the concentrations of ambient ozone and its precursors in Northern Taiwan; (2) associated the risk of respiratory diseases for population younger than 15 years with various ozone metrics in Taipei metropolitan; (3) evaluate the risk of upper respiratory infection associated with atmospheric indices and circulating respiratory viruses for population younger than 15 years in Taipei metropolitan; and (4) assess the mortality risk related to temperature and its long lasting events for population at 65 years old or older in Taipei, Taichung and Kaohsiung.
We used the vital statistics data and the measurements of weather and air pollutants including CO, non-methane hydrocarbon (NMHC), NOx, NO, NO2, PM10, PM2.5,SO2, maximum hourly ozone (O3, max), maximum 8-hour moving average ozone (O3, 8h) and 24-hour average ozone (O3, 24h) in 1994-2007. The insurance reimbursement claims in 2000-2007 from a randomly selected sample containing one million insured individuals were also used. The daily clinic visits for cases on acute respiratory infections (ICD9 CM 460-466, ARI), other diseases of upper respiratory (ICD9 CM 470-478, ODUR) and upper respiratory infection (ICD9 CM 465.9, URI), and daily deaths from all causes (ICD all), circulatory diseases (ICD9 390-459) and respiratory diseases (ICD9 460-519) were retrieved for analyses. The daily virus-specific positive isolation rates were calculated based on the viruses surveillance data in Taipei in 1999-2007. The relative risks (RRs) with 95% confidence intervals (CIs) for mortality and morbidity associated with temperatures, concentrations of air pollutants and viruses positive isolation rates were estimated using generalized linear model (GLM) and distributed lag model (DLM) with Poisson regressions.
The results showed that the concentrations of ambient ozone varied with geographic and seasonal conditions. The concentrations of ozone precursors decreased significantly, while all ozone metrics were increasing over the study period. Ozone generated comparatively efficient in afternoon causing a relatively long ozone exposure and a relatively frequent occurrence of the moderate and high ozone concentrations (80-120 ppb) in Northern Taiwan. The hospital admissions for ARI and ODUR for children aged 14 years and younger in Taipei were significantly correlated with 24-hour average ozone (O3, 24h) during September-January. As the positive isolation rates of circulating respiratory viruses were included in the models, the relative risks of URIs for children were significantly associated with the ambient levels of NO2 and O3, 24h, and the isolation rates of influenza type B, parainfluenza viruses and adenoviruses. The excess risk for URIs was higher in the cold season (November-April) than that in the warm season (May-October).
The cumulative mortality risks for the elderly (65 years and above) due to all causes and cardiovascular diseases were significantly associated with high and low temperature in metropolitans of Taiwan. However, no significant associations between temperatures and mortality from respiratory diseases were observed. There was no significant excess of mortality due to exposing to extreme low/high temperatures for consecutive three days and above. The decreaseing trends of mortality risk to the high temperature but the cold temperature for the elderly population in the studied metropolitans was noticed.
Subjects
ozone
temperature
respiratory infection
relative risk
hospital admission
mortality
Type
thesis
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