Air pollution, aeroallergens and cardiorespiratory emergency department visits in Saint John, Canada

Abstract

Existing studies of the association between air pollution, aeroallergens and emergency department ( ED ) visits have generally examined the effects of a few pollutants or aeroallergens on individual conditions such as asthma or chronic obstructive pulmonary disease. In this study, we considered a wide variety of respiratory and cardiac conditions and an extensive set of pollutants and aeroallergens, and utilized prospectively collected information on possible effect modifiers which would not normally be available from purely administrative data. The association between air pollution, aeroallergens and cardiorespiratory ED visits ( n = 19,821 ) was examined for the period 1992 to 1996 using generalized additive models. ED visit, air pollution and aeroallergen time series were prefiltered using LOESS smoothers to minimize temporal confounding, and a parsimonious model was constructed to control for confounding by weather and day of week. Multipollutant and multi -aeroallergen models were constructed using stepwise procedures and sensitivity analyses were conducted by season, diagnosis, and selected individual characteristics or effect modifiers. In single -pollutant models, positive effects of all pollutants but NO 2 and COH were observed on asthma visits, and positive effects on all respiratory diagnosis groups were observed for O 3 , SO 2 , PM 10 , PM 2.5 , and SO 4 2 À . Among cardiac conditions, only dysrhythmia visits were positively associated with all measures of particulate matter. In the final year -round multipollutant models, a 20.9% increase in cardiac ED visits was attributed to the combination of O 3 ( 16.0%, 95% CI 2.8 ± 30.9 ) and SO 2 ( 4.9%, 95%CI 1.7 ± 8.2 ) at the mean concentration of each pollutant. In the final multipollutant model for respiratory visits, O 3 accounted for 3.9% of visits ( 95% CI 0.8 ± 7.2 ) , and SO 2 for 3.7% ( 95% CI 1.5 ± 6.0 ) , whereas a weak, negative association was observed with NO 2 . In multi -aeroallergen models of warm season asthma ED visits, Ascomycetes, Alternaria and small round fungal spores accounted for 4.5% ( 95% CI 1.8 ± 7.4 ) , 4.7% ( 95% CI 1.0 ± 8.6 ) and 3.0% ( 95% CI 0.8 ± 5.1 ) , respectively, of visits at their mean concentrations, and these effects were not sensitive to adjustment for air pollution effects. In conclusion, we observed a significant influence of the air pollution mix on cardiac and respiratory ED visits. Although in single -pollutant models, positive associations were noted between ED visits and some measures of particulate matter, in multipollutant models, pollutant gases, particularly ozone, exhibited more consistent effects. Aeroallergens were also significantly associated with warm season asthma ED visits.

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

“…For example, Stieb et al (2000) demonstrated significantly increased ED attendances for angina/myocardial infarction with SO 2 only and all cardiac ED attendances with O 3 only, whereas we demonstrated significant percentage increases in ED attendances in IHD for NO 2 and CO, and in cardiac disease for all pollutants (except O 3 ). Unfortunately, Stieb et al (2000) did not provide ICD codes for their categories of CVD and therefore we are unable to directly compare their results with ours. Our results are more consistent with those of Metzger et al (2004), who also found increased ED attendances for all CVD with PM 2.5 , NO 2 and CO, and for IHD with NO 2 .…”

“…Metzger et al (2004) also reported that associations between air pollutants and CVD attendances tended to be highest in the colder months compared to the warmer months. In contrast, Stieb et al (2000) demonstrated that air pollutant effects on ED attendances for cardiac disease were generally greater in the summer months compared to all year effects except for PM 2.5 , where the effect was smaller in summer. We also found mainly negative associations between stroke ED attendances (fewer ED attendances) and air pollutants in the warm period compared to the cool period, and in some cases the negative associations were statistically significant.…”

“…Fewer studies have investigated associations between ambient air pollutants and emergency department (ED) attendances and the majority of these have reported on the associations between air pollution and ED attendances for asthma (Schwartz et al, 1993;Castellsague et al, 1995;Smith et al, 1996;Stieb et al, 1996;Tenias et al, 1998;Fauroux et al, 2000). Only a very small number of published studies have investigated effects of air pollution on cardiovascular disease (CVD) ED attendances (Pantazopoulou et al, 1995;Xu et al, 1995;Stieb et al, 2000;Metzger et al, 2004).…”

Association of asthma symptoms with peak particulate air pollution and effect modification by anti-inflammatory medication use.

“…Our previous asthma panel studies did not find confounding of air pollutant associations by outdoor pollen or fungi (1,7,8). Several time-series investigations have found associations between asthma hospital admissions and both outdoor air pollutants (particles, NO 2 , or O 3 ) and pollen or fungi, but none has found any confounding between aeroallergens and these pollutants (54,60,61). In two studies, there was evidence that SO 2 , NO 2 , and O 3 enhanced the effect of grass pollen on asthma admissions (54,60), although there was a negative interaction between O 3 and tree pollen in one of these studies (54).…”

The Steubenville Comprehensive Air Monitoring Program (SCAMP): Associations among Fine Particulate Matter, Co-Pollutants, and Meteorological Conditions

“…In 1998, the National Research Council 14 stressed the need for additional research to better understand the interactions between PM and gaseous co-pollutants in relation to human health. Since then, several epidemiological studies [15][16][17][18][19][20] have considered the combined effects of co-pollutants and PM on public health and have discovered significant associations between mortality or morbidity and variables such as CO, NO 2 , SO 2 , O 3 , temperature, and aeroallergens. In some instances, these associations were stronger than those between PM and the health endpoints being considered.…”