Seasonal extreme temperatures and short-term fine particulate matter increases child respiratory hospitalizations in a sparsely populated region of the intermountain western United States

Abstract

Background Western Montana, USA, experiences complex air pollution patterns with predominant exposure sources from summer wildfire smoke and winter wood smoke. In addition, climate change related temperatures events are becoming more extreme and expected to contribute to increases in hospital admissions for a range of health outcomes. Few studies have evaluated these exposures (air pollution and temperature) that often occur simultaneously and may act synergistically on health. Methods We explored short-term exposure to air pollution on childhood respiratory health outcomes and how extreme temperature or seasonal period modify the risk of air pollution-associated hospitalizations. The main outcome measure included all respiratory-related hospital admissions for three categories: asthma, lower respiratory tract infections (LRTI), and upper respiratory tract infections (URTI) across western Montana for all individuals aged 0–17 from 2017–2020. We used a time-stratified, case-crossover analysis and distributed lag models to identify sensitive exposure windows of fine particulate matter (PM2.5) lagged from 0 (same-day) to 15 prior-days modified by temperature or season. Results Short-term exposure increases of 1 µg/m3 in PM2.5 were associated with elevated odds of all three respiratory hospital admission categories. PM2.5 was associated with the largest increased odds of hospitalizations for asthma at lag 7–13 days [1.87(1.17–2.97)], for LRTI at lag 6–12 days [2.18(1.20–3.97)], and for URTI at a cumulative lag of 13 days [1.29(1.07–1.57)]. The impact of PM2.5 varied by temperature and season for each respiratory outcome scenario. For asthma, PM2.5 was associated most strongly during colder temperatures [3.11(1.40–6.89)] and the winter season [3.26(1.07–9.95)]. Also in colder temperatures, PM2.5 was associated with increased odds of LRTI hospitalization [2.61(1.15–5.94)], but no seasonal effect was observed. Finally, 13 days of cumulative PM2.5 prior to admissions date was associated with the greatest increased odds of URTI hospitalization during summer days [3.35(1.85–6.04)] and hotter temperatures [1.71(1.31–2.22)]. Conclusions Children’s respiratory-related hospital admissions were associated with short-term exposure to PM2.5. PM2.5 associations with asthma and LRTI hospitalizations were strongest during cold periods, whereas associations with URTI were largest during hot periods. Classification : environmental public health, fine particulate matter air pollution, respiratory infections

“Air That Once Was Breath” Part 2: Wildfire Smoke and Airway Disease – “Climate Change, Allergy and Immunology” Special IAAI Article Collection: Collegium Internationale Allergologicum Update 2023

“…18 [1.20-3.97]), and for upper respiratory tract infections at a cumulative lag of 13 days (1.29 [1.07-1.57]). The strongest PM2.5 associations with hospital admissions for asthma and lower respiratory tract infections occurred during cold periods, in the winter [111]. These recent findings highlight the significance of proactive measures, including air quality monitoring and emergency plans.…”

“…Few studies have evaluated the complex effects of exposures to wildfire smoke, air pollution, and temperature that may act synergistically on health. Landguth et al [111] studied exposure to air pollution and temperature on the risk of hospitalizations and found that short-term increases in PM2.5 were associated with elevated odds of hospitalizations for asthma at lag 7-13 days (1.87 [1.17-2.97]), for lower respiratory tract infections at lag 6-12 days (2. 18 [1.20-3.97]), and for upper respiratory tract infections at a cumulative lag of 13 days (1.29 [1.07-1.57]).…”