Association between fire smoke particulate mateter and asthma-related outcomes, a systematic review and meta-analysis 2019

The purpose of this study was to conduct a systematic review and meta-analysis of the associations between short-term exposure to landscape fire smoke PM2.5 and asthma related outcomes including; hospital admissions, emergency department visits, physician visits, medication use and salbutamol dispensations. To the best of the researchers knowledge, this is the first meta-analysis to obtain summary estimates between fire smoke PM2.5 and asthma related outcomes.
From 181 initial articles, 20 were included for quantitative assessment and descriptive synthesis. Eight studies were from Australia and the USA, four studies were from Canada.
Findings
• Fire smoke PM2.5 levels are positively associated with asthma hospitalisation and ED visits for all ages and sexes
• Females and people over the age of 65 were most susceptible to the landscape fire smoke
• Short term impacts of landscape fire smoke are worse than those from multi-source urban pollution
Short-term exposure to fire smoke PM2.5 is positively associated with asthma-related outcomes, and this is association is higher than from typical multisource pollution. During short fire periods, people are exposed to higher concentrations of particulate matter.
Fire smoke PM2.5 levels were positively associated with asthma hospitalisations and ED visits for all age groups and sexes. Hospital admissions results show that smoke effects could last for multiple days, while for ED visits effects tended to occur on the same day as exposure.
There was a stronger association between fire smoke PM.25 and ED visits/hospitalisations with increasing age. Adults were more susceptible than children, and elderly more susceptible than adults. This is different to evidence related to multisource air pollution where children were most sensitive. Females were more susceptible to fire smoke than males
There is likely an association between fire smoke PM2.5 and physician visits, salbutamol dispensations and medication use in adults but the evidence available is too limited for statistically significant results.