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Mapping smoke exposure & vulnerabilities

If you live in British Columbia, smoky summers are likely a familiar annual occurrence. Every year over 1,600 wildfires rip across the our province and have the potential to blanket the entire land base in smoke. 


Wildfire smoke is made up of a combination of particles and gases which can be harmful to human health. Of the particles, PM 2.5 (particulate matter 2.5 microns or smaller) is particularly harmful as the small size of the particles means that they can move deeper into the respiratory system. Many studies have shown links between exposure to high levels of particulate matter and increased health risks or early death, in particular for young children, older adults, and those with pre-existing heart and lung conditions. In British Columbia, PM 2.5 is the air pollutant of greatest concern to human health.  


It is concerning that, as a result of climate change and a hotter and drier climate with more temperature extremes, more wildfires and wildfire smoke are expected across BC


Wildfire smoke is already affecting people, and with the chance of more frequent large fires in the future, deepening our understanding of the distribution of smoke is extremely important to effectively prepare for the anticipated effects of air pollution in communities across the Province.


At  LGeo, we've mapped where in the province PM2.5 levels have exceeded the provincial air quality standards, and how often it is occurring within the fire season. The maps we've developed show the number of exceedance days by location within each fire season for 2021, 2022 and 2023. 


Smoke patterns are different every year, depending on where fires are, and how smoke is dispersed by weather systems. We can see these differences in the maps of the 2021, 2022 and 2023 smoke seasons, below:

2021

2022

2023


  • In 2021, northern BC had average rainfall, while the southern province had below average rainfall, as a result we can see most of the extreme smoky days occurred in Southern BC in the Thompson-Nicola, Kootenay, and Okanagan regions, and the south east portion of the Cariboo District.

  • The 2022 wildfire season was below normal in terms of number of fires and areas burned and we see fewer days where PM2.5 concentrations exceed provincial standards, compared to 2021 and 2023.

  • The 2023 fire season was the most destructive on record in BC, with many fires in Northern BC. We see very high levels of cumulative exceedance in the Southern Interior and Northeast BC, when considering the Provinces air quality objectives.


Data like this is useful particularly when combined with other information, for example, the population of seniors, or the chronic disease registry. This allows us to know where potential interventions are needed in advance of the next smoke event. Mapping the data allows us to easily visualize those results and to see where the highest concentrations of the most vulnerable and most exposed populations might be. 


To expand on this, we’ve mapped the projected (2045) percentage of the population that are seniors and compared to 2023 exceedance days to show where high smoke hazard and high proportions of vulnerable populations could overlap. 



For example, looking at the projections for seniors, if the regions which currently have high smoke remain the areas with higher numbers of smoky days in the future, we can make assumptions about which areas will be the most vulnerable and thus require significant policy interventions to save lives.


Around Kelowna we can see that people in Rural Central Okanagan and Summerland areas will have a high percentage and quantity of seniors in their population and also potentially have a high number of high smoke days, making those area particularly vulnerable to future wildfire smoke. In contrast, the Kettle Valley region has both a low projected percentage of seniors and a low number of exceedance days, indicating less vulnerability.


We have pulled out some other insights based on 2023 smoke data in BC. The table below shows which regions are the most or least smoky in the province.

Peak smoke exceedance

Most smoky local health areas in BC

Least smoky places in BC

The Northern Rockies region has the highest smoke exceedance days, with a max of 64 exceedance days in 2023. 


Fort St. James North and  Mackenzie are the regions with the next highest exceedance days, each with a peak of 54 days in 2023.


On average, Fort St John and Vanderhoof Rural are the most smoky regions in BC, with an average of 23 and 22 smoke exceedance days in 2023, respectively.


Fort St John is a relatively small area with little variation in smoky days, leading to the high average number of exceedance days



  • Haida Gwaii South

  • Haida Gwaii North

  • Prince Rupert

  • Smithers

  • Terrace

These places do not have any days exceeding air quality standards.

Methodology


The source model of the smoke data is from FireSmoke Canada who, during the fire season (April to September), publish up to four Canada-wide smoke forecasts a day, each forecast with updated meteorology and fire data. Forecasts show the location of smoke plumes, and the data contains the corresponding PM2.5 concentrations. 


We used the modeled PM2.5 concentrations averaged over a rolling 24 hour period to compare against the provincial 24 hour standard of 25µg/m3 of PM2.5. Days where areas exceeded the provincial limits were labeled as exceedance days. We then connected population forecasts from BC Statistics connected to  populated places to understand where  areas of smoke will overlap populations of interest. 


Extensions

we are just getting started with our analysis of hazards and future vulnerabilities, if you have any ideas on improvements or want to jam out on geonerdery drop us a line we are always happy to talk spatial!



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