Air Pollution and Daily Mortality in Birmingham, Alabama

Abstract

Several recent studies have reported associations between common levels of particulate air pollution and small increases in daily mortality. This study examined whether a similar association could be found in the southern United States, with different weather patterns than the previous studies, and examined the sensitivity of the results to different methods of analysis and covariate control. Data were available in Birmingham, Alabama, from August 1985 through 1988. Regression analyses controlled for weather, time trends, day of the week, and year of study and removed any long-term patterns (such as seasonal and monthly fluctuations) from the data by trigonometric filtering. A significant association was found between inhalable particles and daily mortality in Poisson regression analysis (relative risk = 1.11, 95% confidence interval 1.02-1.20). The relative risk was estimated for a 100-micrograms/m3 increase in inhalable particles. Results were unchanged when least squares regression was used, when robust regression was used, and under an alternative filtering scheme. Diagnostic plots showed that the filtering successfully removed long wavelength patterns from the data. The generalized additive model, which models the expected number of deaths as nonparametric smoothed functions of the covariates, was then used to ensure adequate control for any nonlinearities in the weather dependence. Essentially identical results for inhalable particles were seen, with no evidence of a threshold down to the lowest observed exposure levels. The association also was unchanged when all days with particulate air pollution levels in excess of the National Ambient Air Quality Standards were deleted. The magnitude of the effect is consistent with recent estimates from Philadelphia, Steubenville, Detroit, Minneapolis, St. Louis, and Utah Valley.

Estimating Fuel Cycle Externalities: Analytical Methods and Issues, Report 2

“…This association has been reported for Detroit (Schwartz 1991), St. Louis and Easter Tennessee , Utah Valley (Pope et al 1992), Minneapolis (Schwartz 1992), and Birmingham, Alabama (Schwartz 1993). While there will continue to be some uncertainty about the precise magnitude of the effect, these studies tend to support the quantitative estimates of the studies reported above.…”

Exposure of Chronic Obstructive Pulmonary Disease Patients to Particulate Matter: Relationships between Personal and Ambient Air Concentrations

“…[1][2][3] These studies also indicate higher relative risk estimates for the elderly and for those with pre-existing respiratory or cardiovascular diseases. 1,[4][5][6] There is limited information about the contributions of particles of outdoor origin to actual human exposures of such at-risk groups to support the plausibility of these epidemiological findings.…”

Effects of air pollutants on acute stroke mortality.

“…We used a generalized additive model (GAM) (11) to regress daily stroke death counts for each pollutant, while controlling for seasonal and longterm trends, day of the week and meteorologic influences (temperature, relative humidity, and barometric pressure) (12). Because there was a systematic difference in daily mortality among weekdays, we included terms for days of the week in the models.…”