Notices by Jeff Gilchrist (jeffgilchrist@mstdn.science)

Wildfire smoke - now extra toxic plumes from sun UV

Did you know just one of the many fires burning in Quebec is the size of an entire Canadian province (PEI), or large enough to stretch between the cities of Ottawa and Montreal or Toronto to Niagara Falls? Read on to learn more about why the smoke now smells like plastic and the health impact. 🧵 1/

You can read the unrolled one page version here: https://threadreaderapp.com/thread/1675174138741178371.html

#AirQuality #Wildfires #WildfireSmoke #Ontario #Canada #Quebec

Instead of the classic smell of burning wood in a fireplace or campfire, things are starting to smell more like burned plastic so what is going on? It turns out that when smoke stays in the air for prolonged periods of time, the UV radiation from the sun interacts with all the volatile organic compounds (VOCs) to form even more toxic gases. 3/

Now benzene and formaldehyde are being created in the atmosphere from the smoke + UV radiation which happen to smell like plastic but are toxic and can have very adverse effects on human/animal health ( https://www.theweathernetwork.com/en/news/weather/severe/smelling-plastic-millions-are-in-the-path-of-toxic-smoke-plumes ). H/T: @lisa_iannattone

You can learn more about formaldehyde here ( https://www.epa.gov/indoor-air-quality-iaq/what-should-i-know-about-formaldehyde-and-indoor-air-quality ) and benzene here ( https://emergency.cdc.gov/agent/benzene/basics/facts.asp ).4/

Besides the PM2.5 particles in the smoke that can get into your lungs and bloodstream, wildfires smoke it also full of various toxic gases in the form VOCs and by-products like formaldehyde and benzene as we saw above. 5/

Well fitting respirators like N95 masks will do a great job at filtering out the PM2.5 particles from the air if you are outside, but they are not designed to filter out all the smoke related gases. You can learn more about how filtration material in N95s and HEPA filters actually filter out the tiny PM2.5 particles despite them being smaller than the holes in the material ( https://mstdn.science/@jeffgilchrist/109513395114888571 ). 6/

While it is much better to wear a good mask outdoors during wildfire smoke events that filter the PM2.5 particles than nothing, you are still getting exposed to other toxic gases. There are elastomeric respirators with special cartridges that will filter out both the PM2.5 particles and also various gases which would provide better protection outside from smoke ( https://www.cdc.gov/niosh/npptl/respirators/elastomeric/default.html ). 7/

Ottawa Public Health makes only the raw data available for All causes and respiratory-related emergency department visits to Ottawa hospitals by age group and week ( https://open.ottawa.ca/datasets/ottawa::all-causes-and-respiratory-related-emergency-department-visits-to-ottawa-hospitals-by-age-group-and-week/about ). 2/

If I take the data and plot all the ages together, you can at least see all of the age groups at the same time but it is just the raw numbers.

The graph shows that the # of visits for the age 0-3 group is similar to the 18-54 age group near the top of the graph, and the 80+ age group numbers are very low, similar to the age 12-17 group. 3/

But you aren't seeing the full picture, this is where population rate comes in. The next graph uses the same data but instead of raw numbers shows the rate per 100,000 population in each age group.

You can see with population rate the age 0-3 group is far and above the highest level of all groups while the 18-54 age group which had similar raw numbers is actually the lowest rate. 4/

Why? The 0-3 age group represents only 3.75% of the population in Ottawa but had the same # of visits as the 18-54 age group which represents 49.9% of the population so a much higher percentage of the 0-3 age group is being impacted by respiratory infections resulting in ED visits.

Now you can see the real impact on age, where age 0-3 have the highest ED visit rate followed by age 4-11, and then age 80+ which get hidden when you only look at the raw provided numbers from OPH. 5/

Just to make things a little simpler, the last graph shows the # per 100k population as a stacked percentage so you can easily see which age groups are impacted the most.

The youngest 0-3 age group throughout the year accounts for more than 50% of all respiratory related ED visits per 100K population despite being only 3.75% of the population. 6/

Particles in between those sizes (around 0.3 microns) don't travel in straight lines and also don't zigzag randomly but get carried along with the air as it flows around fibres and likely past fibres so can possibly sneak by respirators even with multiple layers. N95s use a final trick of capturing particles of all sizes using an electric field where even neutral particles will still be attracted (as you can see from neutrally charged styrofoam sticking to a cat with static charged fur). 14/

Some cool images of particles being captured by an N95 respirator. "The 'big'' crystals are about 1.5 microns. The smaller captured particles are as small viruses like COVID." ( https://threadreaderapp.com/thread/1865453640510824790.html ). 🧵 1/

#N95 #Respirator #Virus #Filter

Clean air including ventilation and filtration is the ward that can be implemented at an infrastructure level and people don't need to do anything different to get the benefits like we already benefit from clean water infrastructure. Governments and policy makers need to put the appropriate standards and monitoring in place and then mandate them. 17/

"Learning to live with COVID" means upgrading air quality, now ( https://www.thegauntlet.news/p/learning-to-live-with-covid-means ). 18/

It is estimated that currently 1 in 13 people are infected in Ontario which means there is a 55% chance at least one person in your group of 10 is infected. This jumps to a 70% chance in groups of 15, 86.5% chance with 25 people and 98% chance at that office Christmas party of 50 people.

Estimate from ( https://covid19resources.ca/covid-hazard-index/ ) and calculator available at ( https://docs.google.com/spreadsheets/d/1qokCvvi6oRYRCKtrZuyeUmb5mt4LC9o8nKHLKoAUVAY/edit?usp=sharing ). 🧵 1/

The EPA aerosolized non-pathogenic virus (bacteriophage MS2) and measured particle size (0.01 um to 0.6 um) and concentration during the testing in a 3000 square foot test chamber. They found the virus particle concentration was reduced by 40% after 15 minutes, 97% after 30 minutes, 99.4% after 60 minutes and 99.8% after 90 minutes.

More details about this EPA CR box testing project are described here ( https://twitter.com/MarinaC_Dyb/status/1719349909210472749 ).28/

Just like we expect to have access to clean drinking water, we should be demanding that our governments also provide access to clean air.

Recently 60-Minutes did an episode on The Air We Breathe which can be seen here ( https://www.cbsnews.com/video/indoor-air-systems-public-health-60-minutes-video-2023-10-29/ ). 29/

The most important factor is how well a respirator fits on your face so there is minimal leakage around gaps as some respirators fit people very well and others very poorly. You can learn about my fit testing adventure where I found one mask leaked 70x more than another on my face ( https://pingthread.com/thread/1655331142990528514 ). 24/

Many people have anecdotally discovered and reported that Novavax doses had much lower side effects than when they received an mRNA shot. Multiple studies have now shown this to be the case as well. One preprint study (supported by Novavax) that compares the reactogenicity (frequency of side effects) of Novavax and mRNA vaccines ( https://medrxiv.org/content/10.1101/2023.05.31.23290594v1.full ). H/T: @michaelzlin 10/