Air pollution and health

The health effects of air pollution have been subject to intense study in recent years. Exposure to pollutants such as airborne particulate matter and ozone has been associated with increases in mortality and hospital admissions due to respiratory and cardiovascular disease. These effects have been found in short-term studies, which relate day-to-day variations in air pollution and health, and long-term studies, which have followed cohorts of exposed individuals over time. Effects have been seen at very low levels of exposure, and it is unclear whether a threshold concentration exists for particulate matter and ozone below which no effects on health are likely. In this review, we discuss the evidence for adverse effects on health of selected air pollutants.     

Indigenous health in Australia, New Zealand, and the Pacific

We survey Indigenous health issues across the Pacific with a case study approach that focuses on Australia, New Zealand, Hawai'i, and US Associated Micronesia. For each case study, we provide an overview of the Indigenous population, its colonial history, and current health and social outcomes. In the discussion that follows, we flag some of the key policy initiatives that have been developed to address Indigenous health disadvantage, albeit within the context of continuing debates about Indigenous rights and policy.     

Air pollution and pediatric respiratory disease: Croup

The question of a causative interrelation between air pollution and croup has received considerable attention by the mass media. A series of epidemiological studies has tried to establish a scientific basis for these speculations. Some studies have compared the occurrence of croup with locally measured concentrations of pollutants, while others have observed differences in the incidence of croup between populations subjected to different levels of pollution. Results have so far remained contradictory, most studies have failed to control for other variables, and thus clear-cut evidence for the etiologic role of air pollution has yet not been established on an epidemiological basis. On the other hand, simple croup is caused by viral infection, while recurrent croup is associated with allergy and airway hyperreactivity. Animal studies have documented that air pollution can reduce resistance against viral infections, increase the risk of allergic sensibilization, and induce airway hyperreactivity. Conceivably, air pollution could thus have a supportive role in the development of croup, but this possibility requires further investigation.     

Newborn screening in Australia and New Zealand

Newborn screening began in Australia and New Zealand in the mid-1960's as local and pilot programs and implemented as country or state-wide programs around 1970. There are five programs covering all Australia and one for New Zealand. All screening programs are fully government funded, as is treatment for the conditions found by the screening programs and newborn screening is a universally adopted policy funded by the government. Some have additional involvement in program advisory committees. There are no major problems sustaining existing screening, however, some programs have financial problems with funding for new equipment. Other problems include storage and other uses of residual dried blood samples; consent issues; protocols for action after screening and introduction of expanded (tandem mass spectrometry) screening. New activities vary from program to program--working towards expanded newborn screening and collaborative projects for the evaluation of this screening and development of screening for lysosomal storage disorders. All programs are working towards automation of punching and testing and increased automated data handling and reporting.     

Varicella vaccination in Australia and New Zealand

Varicella-zoster virus has been responsible for a significant disease burden, including hospitalizations and deaths in Australia and New Zealand. Varicella vaccine has been available in Australia since 1999 and, since November 2005, has been funded under the National Immunisation Program for use in all children as a single dose at 18 months of age and in a school-based catch-up program at 10-13 years of age. Recent hospitalization data from Australia show a decline in varicella hospitalizations in children 1-4 years of age, most likely related to vaccination. In New Zealand, varicella vaccine has been available since 1999 but is currently not recommended or funded on the New Zealand national immunization schedule. The anticipated licensure of combination measles-mumps-rubella-varicella vaccines in both countries may lead to future schedule changes.     

Air pollution: a new respiratory risk for cities in low-income countries.

Since the major accidents that occurred in the 1960s, air pollution has commonly been considered as a respiratory risk factor whose effects are most often studied in industrialised countries. Our aim is to show that it is now the turn of low- and middle-income countries to take this risk factor into account. After a discussion of the characteristics of air pollution, how it is diffused and the main known health effects (short- and long-term effects), we describe the specific differences between the cities in the North and the South. As a result of late industrialisation, cities in the South are now faced with pollution from industrial sources and urban traffic with polluting vehicles. The case of Algeria and Morocco illustrates this situation and its potential health risks. In order to prevent the health risks of air pollution in the cities of the South, systems for measuring pollution levels and epidemiological surveillance need to be put in place rapidly. This strategy can only work if it is supported by a strong partnership from industrialised countries.     

The effects of air pollution on the respiratory health of children: a cross-sectional study

To investigate the effects of air pollution on the respiratory health of children, a subject of some controversy, a comparative study was undertaken of 2,385 school children who lived in central urban, peripheral urban, and suburban areas. Daily monitoring of sulphur dioxide and total suspended particle concentrations in all areas showed that pollutant concentrations in central and peripheral urban areas were above commonly accepted safety levels for respiratory health, while concentrations in the suburban area were within acceptable limits. A questionnaire administered to each mother assessed environmental exposure to pollutants in the household, the occurrence of respiratory symptoms as well as lung diseases as diagnosed by a physician, and general information. Children were interviewed about smoking habits and any acute respiratory symptoms. Children also performed standard lung function tests. Results showed that children from both urban areas had lessened pulmonary function and a higher prevalence of bronchial secretion with common colds than did those from the suburban area. These differences persisted after corrections for exposure to indoor pollutants, active or passive smoking, socioeconomic status, and sex. Parental cigarette smoking was related to a fall in forced expiratory volume in 1 second and an increased incidence of acute respiratory illnesses and chronic cough in children. Although boys had higher lung volumes and lower air flow, regression analysis showed no significant influence of the interactions "sex-geographic area" and "sex-smoking" on lung function. It was concluded that air pollution has a significant effect on the respiratory health of children.     

Air pollution and respiratory symptoms in preschool children.

A diary study on a random sample of 625 Swiss children aged 0 to 5 yr was conducted in two cities in Switzerland to investigate the association between air pollution and respiratory symptoms. Total suspended particulates (TSP), SO2 and NO2 were measured by city monitor. In addition, passive samplers inside and outside the home measured NO2 concentration during the 6 wk each child was on the diary. Diaries were filled out by parents, and 20% were validated with the attending pediatrician's case notes. Incidence and duration of symptom episodes were examined separately. The study included any episode, episodes of coughing without runny nose, upper respiratory episodes, and episodes of breathing difficulty. In regressions using 6-wk average pollution that controlled for medical history, NO2 measured outdoors but not indoors was associated with the duration of any symptom. Total suspended particulates were a more significant predictor of duration of any symptom than NO2. The 6-wk average TSP was significantly associated with incidence of coughing episodes and marginally significant as a predictor of upper respiratory episodes. Previous day's TSP was a significant predictor of incidence of upper respiratory symptoms. Annual average of NO2 was associated with the duration of any episode and of upper respiratory episodes. We conclude that the incidence and duration of respiratory symptom episodes are likely associated with particulate concentrations and duration may be associated with NO2.