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Conducted by: Nikolas Krstic, Dr. Sarah Henderson and Jiayun Yao

Evaluating Associations Between BlueSky’s PM 2.5 Forecasts and Salbutamol Sulfate Dispensations. Conducted by: Nikolas Krstic, Dr. Sarah Henderson and Jiayun Yao. http://alg.umbc.edu/usaq/images/892010~112150_DSC_3710.JPG. Summer of 2010 the worst season on record.

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Conducted by: Nikolas Krstic, Dr. Sarah Henderson and Jiayun Yao

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  1. Evaluating Associations Between BlueSky’s PM2.5 Forecasts and Salbutamol Sulfate Dispensations Conducted by: Nikolas Krstic, Dr. Sarah Henderson and Jiayun Yao http://alg.umbc.edu/usaq/images/892010~112150_DSC_3710.JPG

  2. Summer of 2010 the worst season on record

  3. Medical health officers wanted an indicator of population sensitivity to fire smoke

  4. Historical FRP to separate fire-affected and non-fire-affected local health areas with PM monitors

  5. Salbutamol dispensations in fire-affected populations

  6. Salbutamol dispensations in non- fire-affected populations Elliott et al. Environmental Health 2013: 12

  7. 2012 pilot of the BC Asthma Medication Surveillance (BCAMS)

  8. The PM monitoring network has is not comprehensive

  9. Remote sensing aerosol Monitor PM Remote sensing fire Remote sensing smoke Venting index Remote sensing data can help!

  10. Combining multiple data sources allows daily population-weighted estimates for all LHAs Yao & Henderson. Journal of Exposure Assessment and Environmental Epidemiology In press

  11. Smoke = FRP

  12. BlueSkysmoke forecasts can help! http://www.bcairquality.ca/bluesky/west/index.html

  13. 2013 refinements to BCAMS

  14. Unlike BlueSky, the statistical model captures smoke in BC due to long range transport (Siberia in this case)

  15. Effects of forecasted smoke consistent with effects of observed smoke for asthma outcomes Yao et al. EHP 2013: 121

  16. The Primary Objectives • Verify whether BlueSky is a useful forecasting tool in the realm of cardiopulmonary disease prevention. • Determine if there is a positive association between the PM2.5 forecast values from BlueSky and the amount of respiratory reliever dispensations. • Learn if there is an apparent difference between associations using earlier (first 24 hours) and later (following 24 hours) hourly forecasts from the same day. • Find out for which provinces in Western Canada, from a public health utility perspective, would benefit the most from BlueSky’s forecasts. http://www.healthfirst.com/_images/products/ProAirHFA_inhalationAerosol_lrg.jpg

  17. Methodology Pt. I (Data Collection) • Retrieval of BlueSky forecast data for the whole domain for the years 2011-2013 and formation of daily average forecasts from hourly data (24 hour and 48 hour “in-advance” PM2.5 forecasts) in units of µg/m3 . • Computation of population-weighted averages for each of the 89 local health authorities (LHAs) in British Columbia • Spatial mappings for LHAs generated for each combination of forecast type (24/48 hour) and year (2011-2013) • Ascertainment of salbutamol sulfate dispensations, populations and meteorological data for each of the LHAs https://www.vs.gov.bc.ca/stats/images/lhamap.gif

  18. Time series of a few sample LHAs. Provided concrete visualisations of the distributions of the forecast data.

  19. 2011 2012 2013 Spatial mappings for the LHA annual means of the 24 hour daily average forecasts (each colour indicates a quintile)

  20. 2011 2012 2013 Spatial mappings for the LHA annual means of the 48 hour daily average forecasts (each colour indicates a quintile)

  21. Distributions of data for a couple of LHAs. Included are dispensations, forecasts and smoke model estimates.

  22. Methodology Pt. II (Modelling) • Poisson Regression modelling was performed for each of the LHAs for both of the forecast types. • Salbutamol sulfate dispensations (offset by population data to form rates) acted as the dependent variable, while the other variables (forecast values, average temperature, etc.) acted as independent. • Generalized Estimation Equations (GEEs) were used to model the overall association with BlueSky forecasts within British Columbia. Forecast values of zero were initially omitted during modelling. • Comparisons were made to another smoke model with PM2.5 estimates which acted as the “gold standard”. (Yao J. and Henderson S., 2013)

  23. Results • Rate ratios were computed from the parameter estimate for a change of 10 µg/m3 in the forecast variable for each model created (with corresponding confidence intervals) • The existence of a positive association between the two variables, PM2.5 forecast value and salbutamol sulfate dispensations, can be identified by whether the rate ratios exceed 1. • Larger values for the rate ratios will indicate a greater positive association between the two variables. • When it came to the GEEs, a variety of different conditions were used when modelling the data because the resulting rate ratios were initially low. However further variations in the modelling also lead to relatively low rate ratios.

  24. Burns Lake North Thomson DTES Salbutamol Sulfate Dispensations rate ratios for the LHAs of BC with respect to average 24 hour “in-advance” daily forecasts

  25. Salbutamol Sulfate Dispensations rate ratios for the LHAs of BC with respect to average 48 hour “in-advance” daily forecasts

  26. Rate Ratios from the initial set of models. Either month or week of year (WOY) were used as a covariate.

  27. Modelling by dividing the data into LHAs which were “smoke-impacted” and those that were “non-smoke-impacted”, based on counts of zeroes.

  28. Similar to the previous modelling technique, except each data set was further subsetted based on if either of the forecast types were non-zero. Rate Ratios for Smoke Model Estimates based on the same data sets

  29. Current Conclusions • Some LHAs seem to have a strong positive association while others seem to lack any or show a negative association. This is likely attributed to whether they are smoke-impacted. • In regard to the “gold standard” smoke model used, the present models also seem to suggest a weak association for 2011-2013. • Even though it was anticipated that the smoke-impacted LHAs would result in an overall larger positive association compared to initial GEE modelling, present modelling showed this was not the case. • Current results may be caused by the scarcity of wildfires in BC during 2011 and 2013, or due to some other undiscovered factor. • Further detailed analysis will still be required to examine if there is an overall positive association between salbutamol sulfate dispensations and BlueSky PM2.5 forecast values for BC (subtle changes in modelling technique, review of the data). • The next step will be to examine this association for other provinces.

  30. Thank You For Your Time! References: Yao J., Henderson S. An empirical model to estimate daily forest fire smoke exposure over a large geographic area using air quality, meteorological, and remote sensing data. Journal of Exposure Science and Environmental Epidemiology 2013; doi: 10.1038. http://i.huffpost.com/gen/765893/thumbs/o-KELOWNA-WILDFIRE-2003-facebook.jpg

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