Low levels of ambient air pollution during pregnancy and fetal growth among term neonates in Brisbane, Australia.

There is mounting evidence that maternal exposure to ambient air pollution during pregnancy is associated with adverse birth outcomes. We examined birth weight and small for gestational age (SGA <10th percentile for age and gender) among 26,617 singleton full-term births in Brisbane, Australia (July 2000-June 2003), in relation to ambient pollution during pregnancy. We also examined head circumference (HC) and crown-heel length (CHL) among a sub-sample (n=21,432) of the term neonates. Maternal exposure to PM(10), visibility reducing particles (bsp), O(3) and NO(2) was assessed by calculating average exposure estimates over months and trimesters of pregnancy based on a citywide average of the pollutants. Linear and logistic regression models were employed to examine the effect of these pollutants on the birth outcomes after adjusting for potential confounders and season of birth. The regression coefficients were based on an inter-quartile range (IQR) increase in exposure as well as quartiles of exposure with the lowest used as a reference category. Trimester- and monthly specific exposures to all pollutants were not significantly associated with a reduction in either birth weight or HC, or an increased risk of SGA. An IQR increase in NO(2) during the third trimester was associated with a reduction in CHL (beta=-0.15cm, 95% CI -0.25 to -0.05cm) and this was concentrated around exposure during month nine. No other pollutants were associated with a reduction in CHL. In conclusion, there was no strong evidence suggesting that ambient air pollution during pregnancy is associated with sub-optimal fetal growth in Brisbane.

The effects of air pollution on hospitalizations for cardiovascular disease in elderly people in Australian and New Zealand cities.

OBJECTIVE: The goal of this study was to estimate the associations between outdoor air pollution and cardiovascular hospital admissions for the elderly. DESIGN: Associations were assessed using the case-crossover method for seven cities: Auckland and Christchurch, New Zealand; and Brisbane, Canberra, Melbourne, Perth, and Sydney Australia. Results were combined across cities using a random-effects meta-analysis and stratified for two adult age groups: 15-64 years and >/= 65 years of age (elderly). Pollutants considered were nitrogen dioxide, carbon monoxide, daily measures of particulate matter (PM) and ozone. Where multiple pollutant associations were found, a matched case-control analysis was used to identify the most consistent association. RESULTS: In the elderly, all pollutants except O3 were significantly associated with five categories of cardiovascular disease admissions. No associations were found for arrhythmia and stroke. For a 0.9-ppm increase in CO, there were significant increases in elderly hospital admissions for total cardiovascular disease (2.2%) , all cardiac disease (2.8%), cardiac failure (6.0%), ischemic heart disease (2.3%), and myocardial infarction (2.9%). There was some heterogeneity between cities, possibly due to differences in humidity and the percentage of elderly people. In matched analyses, CO had the most consistent association. CONCLUSIONS: The results suggest that air pollution arising from common emission sources for CO, NO2, and PM (e.g., motor vehicle exhausts) has significant associations with adult cardiovascular hospital admissions, especially in the elderly, at air pollution concentrations below normal health guidelines. Relevance to clinical and professional practice: Elderly populations in Australia need to be protected from air pollution arising from outdoor sources to reduce cardiovascular disease.

Associations between ambient air pollution and daily emergency department attendances for cardiovascular disease in the elderly (65+ years), Sydney, Australia.

There are no reported studies on the effects of ambient air pollution on emergency department (ED) attendances in Sydney, Australia. This study aimed to determine associations between ambient air pollutants and ED attendances for cardiovascular disease (CVD) in those aged 65+ years. We constructed daily time series of hospital ED attendances, air pollutants and meteorological factors for the Sydney metropolitan area from 1 January 1997 to 31 December 2001. We used generalised linear models to determine associations between daily air pollution and daily ED attendances and controlled for the effects of long-term trends, seasonality, weather and other potential confounders. Increased ED attendances for all CVD, cardiac disease and ischaemic heart disease were seen with 24-h particulate pollution, 1-h NO(2), 8-h CO and 24-h SO(2). Air pollutants were associated with decreased ED attendances for stroke. The effects of air pollutants on CVD, cardiac disease and stroke attendances were generally greater in the cool period compared to the warm period. The single-pollutant effects of CO, O(3), NO(2) and SO(2) were essentially unchanged in two-pollutant models. Although air pollution levels in Sydney are relatively low compared to similar cities, we have demonstrated associations between ambient air pollutants and ED attendances for CVD in people aged 65+ years. Our study adds to the growing evidence for the effects of ambient air pollution on CVD outcomes even at relatively low ambient concentrations.

The short-term effects of air pollution on daily mortality in four Australian cities.

OBJECTIVE: To examine the short-term health effects of air pollution on daily mortality in four Australian cities (Brisbane, Melbourne, Perth and Sydney), where more than 50% of Australians reside. METHODS: The study used a similar protocol to APHEA2 (Air Pollution and Health: A European Approach) study and derived single-city and pooled estimates. RESULTS: The results derived from the different approaches for the 1996-99 period showed consistent results for different statistical models used. There were significant effects on total mortality, (RR = 1.0284 per 1 unit increase in nephelometry [10(-4).m(-1)], RR = 1.0011 per 1ppb increase in NO2), and on respiratory mortality (RR = 1.0022 per 1ppb increase in O3). No significant differences between cities were found, but the NO2 and particle effects may refer to the same impacts. Meta-analyses carried out for three cities yielded estimates for the increase in the daily total number of deaths of 0.2% (-0.8% to 1.2%) for a 10 microg/m3 increase in PM10 concentration, and 0.9% (-0.7% to 2.5%) for a 10 microg/m3 increase in PM2.5 concentration. CONCLUSIONS: Air pollutants in Australian cities have significant effects on mortality.

The short-term effects of air pollution on hospital admissions in four Australian cities.

BACKGROUND: This paper examines the short-term health effects of air pollution on daily hospital admissions in Australian cities (those considered comprise more than 50% of the Australian population) for the period 1996-99. METHODS: The study used a similar protocol to overseas studies and derived single city and pooled estimates using different statistical approaches to assess the accuracy of the results. RESULTS: There was little difference between the results derived from the different statistical approaches for cardiovascular admissions, while in those for respiratory admissions there were differences. For three of the four cities (for the other the results were positive but not significant), fine particles (measured by nephelometry - bsp) and nitrogen dioxide (NO2) have a significant impact on cardiovascular admissions (for total cardiac admissions, RR = 1.0856 for a one-unit increase in bsp (10(-4) x m(-1)), RR = 1.0023 for a 1 ppb increase in NO2). For three of the four cities (for the other, the results were negative and significant), fine particles, NO2 and ozone have a significant impact on respiratory admissions (for total elderly respiratory admissions, RR = 1.0552 per 1 unit (10(-4) x m(-1)) increase in bsp, RR = 1.0027 per 1ppb increase in NO2, RR = 10014 per 1 ppb increase in ozone for elderly asthma and COPD admissions). In all analyses the particle and NO2 impacts appear to be related. CONCLUSIONS: Similar to overseas studies, air pollution has an impact on hospital admissions in Australian cities, but there can be significant differences between cities.

Air pollution and child respiratory health: a case-crossover study in Australia and New Zealand.

RATIONALE: The strength of the association between outdoor air pollution and hospital admissions in children has not yet been well defined. OBJECTIVES: To estimate the impact of outdoor air pollution on respiratory morbidity in children after controlling for the confounding effects of weather, season, and other pollutants. METHODS: The study used data on respiratory hospital admissions in children (three age groups: < 1, 1-4, and 5-14 years) for five cities in Australia and two in New Zealand. Time series of daily numbers of hospital admissions were analyzed using the case-crossover method; the results from cities were combined using a random-effects meta-analysis. MEASUREMENTS AND MAIN RESULTS: Significant increases across the cities were observed for hospital admissions in children for pneumonia and acute bronchitis (0, 1-4 years), respiratory disease (0, 1-4, 5-14 years), and asthma (5-14 years). These increases were found for particulate matter with a diameter less than 2.5 microm (PM2.5) and less than 10 microm (PM10), nephelometry, NO2, and SO2. The largest association found was a 6.0% increase in asthma admissions (5-14 years) in relation to a 5.1-ppb increase in 24-hour NO2. CONCLUSIONS: This study found strong and consistent associations between outdoor air pollution and short-term increases in childhood hospital admissions. A number of different pollutants showed significant associations, and these were distinct from any temperature (warm or cool) effects.

Atmospheric Poaceae pollen frequencies and associations with meteorological parameters in Brisbane, Australia: a 5-year record, 1994-1999.

Grass pollen is an important risk factor for allergic rhinitis and asthma in Australia and is the most prevalent pollen component of the aerospora of Brisbane, accounting for 71.6% of the annual airborne pollen load. A 5-year (June 1994-May 1999) monitoring program shows the grass pollen season to occur during the summer and autumn months (December-April), however the timing of onset and intensity of the season vary from year to year. During the pollen season, Poaceae counts exceeding 30 grains m(-3) were recorded on 244 days and coincided with maximum temperatures of 28.1 +/- 2.0 degrees C. In this study, statistical associations between atmospheric grass pollen loads and several weather parameters, including maximum temperature, minimum temperature and precipitation, were investigated. Spearman's correlation analysis demonstrated that daily grass pollen counts were positively associated (P < 0.0001) with maximum and minimum temperature during each sampling year. Precipitation, although considered a less important daily factor (P < 0.05), was observed to remove pollen grains from the atmosphere during significant periods of rainfall. This study provides the first insight into the influence of meteorological variables, in particular temperature, on atmospheric Poaceae pollen counts in Brisbane. An awareness of these associations is critical for the prevention and management of allergy and asthma for atopic individuals within this region.

Air pollution and its health impacts: the changing panorama.

Urban air pollution levels are associated with increased mortality and cardiorespiratory morbidity. These health effects occur even at exposure levels below those stipulated in current air-quality guidelines, and it is unclear whether a safe threshold exists. Air pollution in Australia and New Zealand comes primarily from motor vehicle emissions, electricity generation from fossil fuels, heavy industry, and home heating using wood and coal. In individual patients a direct link between symptoms and air pollution exposure may be difficult to establish and may not change their clinical management. However, avoiding exposure during periods of peak pollution may be beneficial. Although there is some evidence that urban air pollution in Australia and New Zealand has been decreasing (through reduced car use, improved emission-control technology and use of more energy-efficient devices in the household and in industry), pollution levels are still unsatisfactory. Further reductions may prevent hundreds of cardiorespiratory hospital admissions and deaths each year.