What is PM2.5 and Why Do I Itch?

 

PM refers to particulate matter that hangs in the air creating haze and off-color sunshine.  The 2.5 refers to the size of these particles, which is 2.5 microns or less, which are produced by vehicle exhaust, burning fuels (wood, oil, coal), and wildfires. They are easily carried over long distances. As you can well imagine, such tiny particles can pass deep into lungs and through blood vessel walls into the bloodstream thus increasing risk for heart and lung disease. Several thousand of the smaller particles could fit on the period at the end of this sentence. What came as a surprise to me as I investigated this hazardous air-borne matter was its effect on the skin.

 “These pollutants often contain chemical compounds that act like keys, allowing them to slip past the skin’s outer barrier and penetrate into cells, where they can disrupt gene transcription, trigger oxidative stress or cause inflammation.” 

 Past studies have found a link between atopic dermatitis (AD, aka eczema) and air pollution in cities with high background levels of PM2.5 from cars and industry.  The latest study, published in April of this year in JAMA Dermatology, was conducted by researchers in San Francisco as they perused medical records from November, 2018.  At that time, a serious wildfire nearby (Camp Fire), while extinguished in about two weeks, caused a notable increase in the number of clinic visits for itching and new rashes in both pediatric and adult populations. The authors of the study concluded that even short-term exposure to high PM2.5 environmental particulate matter is associated with increased skin woes, and the majority of new patients scratching n’ rashing had no history of dermal disorders.

 Ugh, walked this morning through the PM2.5 haze, and now I’m itching all over! Little red itchy bumps on the forearm; PM2.5 or creepy little noseeums (a catch-all name for 5,000 species of tiny biting flies)?