Winter Temperature Inversions and Emergency Department Visits for Asthma in Salt Lake County, Utah, 2003–2008

Abstract

Background: Winter temperature inversions—layers of air in which temperature increases with altitude—trap air pollutants and lead to higher pollutant concentrations. Previous studies have evaluated associations between pollutants and emergency department (ED) visits for asthma, but none have considered inversions as independent risk factors for ED visits for asthma.Objective: We aimed to assess associations between winter inversions and ED visits for asthma in Salt Lake County, Utah.Methods: We obtained electronic records of ED visits for asthma and data on inversions, weather, and air pollutants for Salt Lake County, Utah, during the winters of 2003 through 2004 to 2007 through 2008. We identified 3,425 ED visits using a primary diagnosis of asthma. We used a time-stratified case-crossover design, and conditional logistic regression models to calculate odds ratios (ORs) and 95% confidence intervals (CIs) to estimate rate ratios of ED visits for asthma in relation to inversions during a 4-day lag period and prolonged inversions. We evaluated interactions between inversions and weather and pollutants.Results: After adjusting for dew point and mean temperatures, the OR for ED visits for asthma associated with inversions 0–3 days before the visit compared with no inversions during the lag period was 1.14 (95% CI: 1.00, 1.30). The OR for each 1-day increase in the number of inversion days during the lag period was 1.03 (95% CI: 1.00, 1.07). Associations were only apparent when PM10 and maximum and mean temperatures were above median levels.Conclusions: Our results provide evidence that winter inversions are associated with increased rates of ED visits for asthma.

Incidence of primary spontaneous pneumothorax is not associated with microclimatic variations. Results of a seven-year survey in a temperate climate area

“…The health condition may however be influenced by various seasonal changes. Several studies, with different strength of evidence, showed that some associations may exist between meteorological variables and different clinical conditions such as stroke [13], myocardial infarction [14], renal colic [15], atrial fibrillation [16], asthma [17], epistaxis [18], and arthritic pain [19]. Psychiatric emergencies are also influenced by climatic variables, although with variable degrees of strength and evidence [20,21].…”

Temporal structure of thermal inversions in Łeba (Poland)

“…A study conducted by Beard et al (2012) during winter seasons in Salt Lake County (USA) revealed an association between inversions and emergency visits to the hospital for asthma. Abdul-Wahab et al (2005) states that the daily average number of hospital visits in Oman increased with an increase in the inversion depth and strength of surfacebased inversions.…”

Receptor model source attributions for Utah's Salt Lake City airshed and the impacts of wintertime secondary ammonium nitrate and ammonium chloride aerosol

“…These elevated PM 2.5 levels cause adverse health effects locally. For example, the state of Utah found that the odds of an emergency department visit in Salt Lake County, with a primary diagnosis of asthma, are 42% greater during days 5-7 of prolonged inversions than for noninversion days (Beard et al, 2012). During a particularly extreme cold-air pool event in 2004, 24-hr average PM 2.5 concentrations exceeded 100 mg/m 3 (Malek et al, 2006), while more recent maximum daily average concentrations have been in the range of 50-70 mg/m 3 .…”