In “Can PM 2.5 lead to early mortality?,” I posed the question: “… (I)f PM 2.5 is not unhealthy, then why a corresponding scale related to such and at times fine particulate matter readings go above 100, why the associated ‘Unhealthy’ or ‘Hazardous’ designations?”
Well, there is more regarding soot as it has to do with its health impacts. According to the California Environmental Protection Agency Air Resources Board (ARB) in a Jan. 7, 2014 news release, groundbreaking research was conducted to determine the effects of soot on the immune systems and lungs of infant monkeys.
“An ARB-funded study at the California National Primate Research Center showed for the first time that exposure to high levels of fine particle pollution at infancy adversely influences development of the branch of the immune system that combats infectious disease, and adversely affects the development of lung function.”
The research centered on approximately 2,000 Northern California wildfires in 2008 during June. Over a 10-day period, according to ARB, measured levels of fine particulates were uncharacteristically high.
PM 2.5 readings at the Primate Center, according to ARB, ranged from a low of 50 to 60 micrograms per cubic meter of air to a high of almost 80. The federal health standard for such particulate matter is 35 micrograms per cubic meter.
Meanwhile, no exceedances of the federal health standard for fine particulate matter were recorded the following year, and the absence of wildfires in 2009 thus afforded researchers the opportunity to make a year-to-year comparison of “smoke-exposed” monkeys in 2008 to those in 2009 not exposed, the ARB insisted.
“The study was designed to investigate the effects of air pollution on infants, taking advantage of a rare case of scientific serendipity: as it happens, the high levels of particle pollution coincided with the end of the season when rhesus monkey babies are typically born at the federally funded Primate Center. The rhesus macaque monkeys, including a significant number of monkeys between 1 and 3 months old, live full time in outdoor field cages at the facility, and were exposed to the elevated levels of air pollution 24 hours a day as a result of the fires.”
The ARB noted additional significant study findings, such as:
- Several parameters of immune system function that help protect the body from bacterial infection were found to be reduced in the animals exposed as infants to the wildfire PM2.5, compared to animals born the following year.
- This is the first time fine particle pollution has been shown to influence the branch of the immune system that combats infectious disease.
- Unexpectedly, investigators found a link between reduced immune system function and abnormalities in lung function, particularly in female animals.
(Source: “Study links wildfire smoke exposure to reduced immune system function: 10-day episode of wildfire smoke in 2008 offers unexpected primate research opportunity,” ARB News Release, California Environmental Protection Agency Air Resources Board, Jan. 7, 2014, http://www.arb.ca.gov/newsrel/newsrelease.php?id=558).
The ARB in the release further pointed out that no investigative studies linking such exposures to health consequences over the long-term have been conducted as of yet.
Image above: U.S. National Institutes of Health: National Heart, Lung and Blood Institute