Wildfire Smoke: Blankets the West – Air Quality Worst in History

Smoke from wildfires blanketing the West Coast in the last few months have caused some of the planet’s worst air quality, with smoke reaching the East Coast and  Europe. 

The EPA PM 2.5 AQI (Air Quality Index) in Portland and Eugene OR and Vancouver British Columbia reached over 700 last month, according to PurpleAir, a network of local indoor and outdoor air sensors purchased and used by individuals throughout the U.S. and uploaded to a national map in real time. This would make them the most polluted cities in the world for that period. And as the EPA AQI only goes to 500, the EPA is clear that recommendations for readings above 500 is to “remain in a room or building with filtered air”.   

Dr. Walter Crinnion lectured many times about air filtration as probably the most effective intervention for reducing exposure to a myriad of environmental toxicants. His advice is more crucial today than it has ever been.  

Below is a screenshot of the live PurpleAir map taken at 6:30 pm on Sept. 30th, 2020 showing multiple readings in N. California over 150. According to the EPA, readings between 151-200: “everyone may experience health effects if exposed for more than 24 hours, members of sensitive groups may experience more serious health effects.”  

When the air quality index rises over 400 the EPA is clear: “Health warnings of emergency conditions if exposed for 24 hours. The entire population is more likely to be affected.” An emergency condition includes the following: acute respiratory distress, myocardial infarction and stroke.  

At this very moment, according to the World AQI tracking data, San Francisco (AQI of 108) has about the same level of polluted air as Beijing (122) but more polluted than Shanghai (88) or Wuhan (91).  

A recent study on wildfire smoke exposure was conducted in Seeley Lake, MT (outside of Missoula) where residents experienced an average AQI of 220.9 μg/m3 for 6 weeks in the summer of 2017. Follow-up in 2018 and 2019 showed that the residents (specifically those over 65) had a significant decrease in lung function (FEV1/FVC ratio: forced expiratory volume in first second/forced vital capacity). More than twice the number of participants fell below the lower limit of normal than would have been expected one year following the wildfire event (10.2% in 2017 to 45.9% in 2018). This decrease in lung function remained two years post exposure in 34% of the tested population.  

The study authors concluded that the period of 6 weeks of exposure of AIQ around 220 had long lasting effects. Although the median age in this study was 63 (so more likely to have respiratory problems), the decline in lung function was not expected for that age group.  

FEV1 values are used to determine whether lung function is declining at a normal rate based on age. According to the Mayo Clinic, the expected annual decline in pulmonary function in FEV1 is 30 mL for males and 25 mL for women. The Seeley Lake cohort (specifically those without woodstoves) saw a decline in their FEV1 from 289.3 to 189.7 mL = 100 mL over a year.  

As climate scientists predict more wildfires and higher levels of air pollution over the next 30 years for the West, what does this mean, for ourselves and our patients right now and for the indeterminate future?  

To answer that question, we have to look at what is in wildfire smoke and how it damages the lungs and cardiovascular system.  

Unfortunately wildfire smoke contains more than particulate matter. Burning trees and bushes give off solvents (benzene, formaldehyde, toluene, xylene), harmful gases like ozone, nitrogen and sulfur dioxide, carbon monoxide and respiratory irritants like acrolein. The further the smoke drifts, the more ozone is created when the gases in the smoke are exposed to sunlight. Ozone is a serious lung toxicant, contributing to damage that can cause COPD in both adults and children. 

Woodsmoke also contains arsenic, mercury, and PAH (polycyclic aromatic hydrocarbons) all known carcinogens and DNA-damaging toxicants.  

Wildfire smoke, also known as carbon black, appears to cause glutathione depletion in macrophages and monocytes and also causes massive amounts of ROS (reactive oxygen species aka free radicals) which not surprisingly, leads to glutathione depletion. These ROS (particularly hydroxyl radicals) have been identified as the culprit in wood smoke-related lung injury in animals. 

The Wildfire Smoke Action Plan previously created by the EHS Faculty who presented research on this subject in a webinar series (view here) included two very crucial recommendations for wildfire smoke exposure: 

Sulforaphane 30-50 mg. day for adults in a highly polluted city in China increased the ability to detoxify air pollution exposure via glutathione-conjugated pollutant excretion (glutathione-derived conjugates of benzene and acrolein).  

NAC (typical adult dose 1800 mg/d) reduces lung inflammation, corrects the reduction in GSH levels and airway reactivity from diesel particle exhaust, blocks pro-inflammatory cytokine production resulting from air pollution exposure, and reduces cyto- and genotoxicity from air pollution exposure.  

NAC is available OTC- the only contraindication is peptic ulcer. Sulforaphane is also available OTC and can be obtained in significant quantities through dietary sources- the highest concentration is found in broccoli sprouts- which are inexpensive when grown at home. According to the Brassica Chemoprotection Laboratory and Department of Pharmacology and Molecular Sciences, at Johns Hopkins Univ. School of Medicine - broccoli sprouts contain approximately 250 mg. sulforaphane per 100 gram serving.