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Monday, May 12, 2014

Testing For Evidence of Fukushima Part IV: Is wood burning and radioactive fallout a deadly combination for the Pacific Northwest?

Four WA City Comparison from http://airgraphing.pscleanair.org/
Data from https://fortress.wa.gov/ecy/enviwa/

In Part I of this series, I have described how I have collected three years worth of external air filters sealed in plastic since before March 11, 2011. I change them out every 45 days as they are so filthy with smoke and soot! My hypothesis is that  Fukushima radionuclides bio-accumulate in our forests. As quite a few of my neighbors burn for heat, I should see a gradual increase Cesium137, Strontium90, Iodine131, etc. as the months progress since the accident(s) at Fukushima. In this post, I will look at fine particulate (PM-2.5) emissions; their effect on health and compare our PM-2.5 emissions in Bellingham with other station "polygons" in WA state. Excellent background on PM-2.5 can be found at Wikipedia. Google Scholar has many available academic articles on PM-2.5.

Wood Burning is considered one of the top health hazards in WA State. Limiting fine particle pollution ( less than 2.5 microns) is considered a top monitoring priority for ECY, WA and the EPA. Both the Northwest Clean Air Agency, UW, and ECY have issued health warnings and research describing the disastrous effects of wood burning on human health. A number of areas in Washington of noted interest for their high PM-2.5 levels including the Tacoma-Pierce non attainment area, The Duwamish Valley in Seattle and Whatcom County's Columbia Valley.  However, in some recent data analysis, I have discovered that urban Bellingham is extraordinarily high in total volume of PM2.5 pollution. Although rates recorded by the Yew Street station never reach the same high levels as Tacoma and Yakima station, we burn a longer season in both Anacortes and Bellingham; thus possibly creating a total yearly volume of PM-2.5 emissions equal to or greater than an EPA non attainment area.

The danger of wood smoke is something I have become aware of personally while living with allergic asthma in the Columbia neighborhood.  Wood burning in a dense city neighborhoods is essentially multiple ground level smoke stacks emitting fine particulate. The danger of PM 2.5 lies in the small size of the particle. At 2.5 microns ("micrometers") or less, a wood smoke particle is considered small enough to float into the bronchi and perhaps into the blood stream. In fact it is sometimes said that PM 2.5 behaves like a gas. Here is an EPA picture for some perspective:


The charts below show PM-2.5 particulate emissions for Yakima, Tacoma, Bellingham, and Anacortes for the six month period November 2013 through April 2014 and then again for the two month period March - April 2014. Clearly, both these Yakima and Tacoma station collect more PM 2.5 than either the stations in Anacortes or the Yew Street Station in Bellingham.  The stations are deployed in "polygons" by the NWCAA and ECY, WA. The Yew Street Station in Bellingham is some distance from the heavy burning I experience in the North Columbia and Birchwood neighborhoods. Note that Bellingham exceeds all three of the other stations in March and April. This is probably the result of our 9 - 10 month rainy season here. Some wood burners in my neighborhood start burning in October and continue to burn into summer months if the weather is still cold.

Data from from http://airgraphing.pscleanair.org/
The charts far below may be a somewhat suspect analysis. Let me explain. PM2.5 particulate is measured as a volume rate: micrograms / cubic meter or ug/m^3. This gives an amount for a given density usually computed as an (hourly) average. In the charts below, I have simply summed all the hourly averages to create a total for the six month period November 2013 - April 2014 and again for March 2014 - April 2014.   This may well be a mathematically disingenuous method to compare total PM 2.5 exposure over time:

11/13 - 4/14
ANA 20716.96
TAC 37465.17
BHA 42719.20
YAK 49472.35

3/14 - 4/14
TAC  5175.72
YAK  6208.33
ANA  6346.09
BHA 14673.30

Recommendations are usually made on the basis of the hourly average. EPA is now recommending wood stoves that produce no more that 12 ug/m^3. However, this volume rate limit will not necessarily determine total exposure to wood smoke particles given that some communities will burn more months than others or burn longer hours than others.  PM-2.5 sources can originate from a number of different sources and contains hundreds of different chemicals. Bellingham would have both industrial, urban, and rural sources. [1,2]  A source apportionment that would seek to understand species contribution to aerosols and PM-2.5 particulate could be a critical piece in understanding Whatcom County and Bellingham Cancer rates.

Data from http://airgraphing.pscleanair.org/
An analysis about exposure begets a much longer discussion over the effect of wood smoke and PM 2.5 particulate on human health. The question  I am interested in today runs something like this:
Specify a given rate for any and all anthropogenic radionuclide fallout for a specific region (e.g Whatcom County) . Establish an arboreal uptake for that fallout and environmental pollution rates for those arboreal sources burned for fuel or waste.  Now plot, for any given total volume of PM 2.5 pollution from locally sourced wood burning, how much anthropogenic radionculides become either:
  •  lodged directly in the lung tissue 
  •  permeate lung tissue to enter the blood stream
With such numbers computed, a probability analysis of occurrence of related forms of cancer and disease and subsequent death rates could be estimated. I can find a limited number of academic articles describing radionuclides in wood smoke; almost all of which discuss arboreal uptake from naturally occurring uranium, radium and their respective decay chain isotopes. For an example, see "Contribution of biomass combustion to air pollutant emissions" by Cátia Vanessa Maio Gonçalves. 

Numerous academic studies have predicted the long term global spread of Fukushima fallout. (See a collection of such articles here.) A thorough source analysis of PM2.5 sources would help health professionals in Whatcom understand any increase in Cancer rates in Bellingham and Whatcom County and other West Coast regions where biomass from local arboreal or agriculture sources is burned for heat or waste removal.