Time series analysis of fine particulate matter and asthma reliever dispensations in populations affected by forest fires

Abstract

BackgroundSeveral studies have evaluated the association between forest fire smoke and acute exacerbations of respiratory diseases, but few have examined effects on pharmaceutical dispensations. We examine the associations between daily fine particulate matter (PM2.5) and pharmaceutical dispensations for salbutamol in forest fire-affected and non-fire-affected populations in British Columbia (BC), Canada.MethodsWe estimated PM2.5 exposure for populations in administrative health areas using measurements from central monitors. Remote sensing data on fires were used to classify the populations as fire-affected or non-fire-affected, and to identify extreme fire days. Daily counts of salbutamol dispensations between 2003 and 2010 were extracted from the BC PharmaNet database. We estimated rate ratios (RR) and 95% confidence intervals (CIs) for each population during all fire seasons and on extreme fire days, adjusted for temperature, humidity, and temporal trends. Overall effects for fire-affected and non-fire-affected populations were estimated via meta-regression.ResultsFire season PM2.5 was positively associated with salbutamol dispensations in all fire-affected populations, with a meta-regression RR (95% CI) of 1.06 (1.04-1.07) for a 10 ug/m3 increase. Fire season PM2.5 was not significantly associated with salbutamol dispensations in non-fire-affected populations, with a meta-regression RR of 1.00 (0.98-1.01). On extreme fire days PM2.5 was positively associated with salbutamol dispensations in both population types, with a global meta-regression RR of 1.07 (1.04 - 1.09).ConclusionsSalbutamol dispensations were clearly associated with fire-related PM2.5. Significant associations were observed in smaller populations (range: 8,000 to 170,000 persons, median: 26,000) than those reported previously, suggesting that salbutamol dispensations may be a valuable outcome for public health surveillance during fire events.

A statistical model for determining impact of wildland fires on Particulate Matter (PM2.5) in Central California aided by satellite imagery of smoke

“…One method used to quantify contribution of fire to air quality is to define a circle of a given radius around each PM monitor and assume that all fires within the circle have an effect at the monitoring site (Elliott et al, 2013). However, meteorological conditions such as wind speed and direction also need to be taken into account (Preisler et al, 2005;Preisler et al, 2010;Moeltner, 2013) in order to assess contribution from a particular fire.…”

Changes in ozone and precursors during two aged wildfire smoke events in the Colorado Front Range in summer 2015

“…Wildfire smoke can be transported over thousands of kilometers, and exposure to wildfire smoke has significant impacts on human health (Künzli et al, 2006;Rappold et al, 2011;Elliott et al, 2013). While US emissions of most major air pollutants are declining (Pinder et al, 2008), increasing fire activity suggests that wildfires may have a greater relative impact on US air quality in the future (Val Martin et al, 2015).…”

Health effects of the 2012 Valencia (Spain) wildfires on children in a cohort study

“…The exposure to elevated quantities to PM is associated with a more severe detrimental lung function in individuals affected by respiratory diseases. (Pope and Dockery 2006) With regard to wildfire episodes, time series studies performed in several locations obtained an increasing number of hospital admissions due to asthma during wildfire period (Elliott et al 2013;Johnston et al 2002). Vora et al (2011) showed that the 2007 San Diego wildfires may have led to an increase in airways inflammation in asthmatics.…”

“…Previous research of wildfire effects was mainly focused on adult mortality and morbidity endpoints (Analitis et al 2012;Caamano-Isorna et al 2011;Crabbe 2012;Delfino et al 2009;Elliott et al 2013;Emmanuel 2000;Hanigan et al 2008;Johnston et al 2007;Vora et al 2011). However, to date, there is still limited research on the impact of wildfire smoke on vulnerable population groups, such as children (Jalaludin et al 2000;Künzli et al 2006;Mirabelli et al 2009).…”