Strategies to Mitigate Health Impacts During Current Forest Fire Season

The smoke that rolled into Teton Valley on Friday Aug 6 was a public health emergency for everyone. It was not just unhealthy for people with underlying coronary and pulmonary problems. The City of Driggs now has an air quality monitor on the purple air network. that measures PM2.5 particulate air pollution. Friday afternoon this monitor read pm2.5 AQI of 175.  This was equal to a pm2.5 of 100 ug/m3. This was in the red zone (151 to 200)  which means unhealthy for everyone. An orange AQI  (101 to 150) means unhealthy for sensitive groups. During many years of monitoring air quality in Salt Lake City, I never saw air quality so toxic to one’s health as this.

As per the Clean Air Act, The Environmental Protection Agency required cities over 50,000 population to measure ozone, particulates, carbon monoxide, lead, nitrogen dioxide and sulfur dioxide. So the PurpleAir’s devices are very useful in rural communities. They measure only Pm2.5 which is particulate matter that is 2.5 microns in diameter and smaller or 1/30th the diameter of a human hair. These particles pass deep into the lungs. PM 2.5 pollution comes from trucks, buses, automobiles, industrial sources, and forest fires.  The measurement of pm2.5 in ug/m3 is more useful to me than AQI in that all of the research that has been done on air quality uses absolute concentrations in ug/m3. Like covid public policy, The EPA and AQI messaging is also constrained by politics. The scientific advisory committee to the EPA always pushes for stricter guidelines because there is no safe numbers when it comes to air pollution. Cities and counties often don’t want to enforce polluting sources like oil refineries or coal fired power plants because as in the case of wildfires, smoke can travel hundreds of miles. On the purple air monitor it is easy to convert AQI to Pm2.5 in ug/m3. The EPA has set a 24-hour standard for PM 2.5 at 35 mcg/m3.  This means that if a city averages over 35 ug/m3 for that day, it is out of compliance with the EPA . This corresponds to a AQI of 99 or yellow. The annual average standard set by the EPA is 12 mcg/m3 which corresponds to an AQI of 51 or yellow. In other words cities averaging over 12 mcg/m3 are out of compliance. Generally this means that a city or county has 3 years to come into compliance with the Epa standards. In Salt Lake County, they don’t let children have recess outside when pm2.5 greater than 75 ug/m3.

I have learned that bad visibility during winter inversions and fire season do not always correspond to unhealthy air. For example, when the smoke is high in the sky, it can look bad, but ground level particulates are not necessarily unhealthy. Many folks cough, get watery eyes or nasal congestion when air quality deteriorates. However one can measure deterioration in lung function even before one becomes symptomatic. Asthmatics and folks with COPD should measure their peak flow during times of smoke; it just might prevent an emergency room visit. Experts disagree on the exact number; but I personally would not do strenous outdoor exercise at pm2.5 greater than 35= aqi of 100. If someone has a pre- existing condition, I would advise much more caution. Walking the dog is obviously quite different from a strenuous outdoor activity.

Studies have shown a significant association between fine particle exposure and premature death from heart or lung disease. The effects of fine particles include: cardiac arrhythmias, heart attacks, pneumonia, asthma attacks, lung cancer and bronchitis. Specifically, particulate air pollution accelerates atherosclerosis and inflammation throughout the body and decreases heart rate variability. A study in Utah looked at 12,000 folks who had had coronary angiography. These were people who had undiagnosed chest pain or who had experienced heart attacks. This study showed a 4.5% increase in heart attacks on days with PM 2.5 increases of 10 mcg/m3. The results were linear so that on a smoggy day with a level of PM 2.5 of 60 would have a 25% increase in heart attacks in this vulnerable population.  A 4-year national study of 65,000 women found that a 10 mcg/m3 rise in chronic PM 2.5 exposure resulted in a 24% increased risk of cardiovascular events, a 76% increased risk of death from heart disease, and a 35% increased risk of stroke.

The easiest place to look at blood vessels in the body is the retina of the eye. The size of these vessels constrict with pm2.5 pollution. On the PurpleAir map, I use the drop down menu that gives a 10 minute average. Other possibilities are one day average.

Here are some useful possible strategies to mitigate the health impacts during our current forest fire season:

  • Keep your doors and windows closed.
  • Buy an indoor air or Hepa filter for your home. These can range from $175 to $800. They can be moved to different rooms and the speeds can be changed to make less noise.
  • Keep your motor vehicle on recirculate.
  • If you have an air conditioning unit, Keep it on recirculate.
  • Vacuuming your home can kicks up dust.
  • A well fitted n-95 or k-95 mask can be used outdoors to mitigate health hazards.

– Howie Garber M.D is a retired ER physician