Study concludes wildfire smoke causes lower infant birth weight

An economics researcher found that infants’ proximity to smoke pollution while in utero affects birth weight.

Above: Whitetail Fire in South Dakota

(Originally published at 6:17 p.m. MST January 22, 2018)

When researchers seek to determine a single or primary cause for a human health problem, they know they’re battling uphill. Our environments are complex, multifaceted, and permeated by a seemingly infinite number of factors that could shape us. Rare is the circumstance that is so ideal, at least from a researcher’s perspective, that one can sift through the noise and emerge with a definitive root of an issue.

That is, of course, unless nature is on your side — as was the case for UNLV economics professor Shawn McCoy and his University of Pittsburgh economics colleague Xiaoxi Zhao.

It’s hard to imagine anything positive coming out of wildfires. They’ve become six times more likely to occur and four times as large since the 1980s, McCoy said, due to climate and population changes. And yet for his research, which demonstrates that proximity to smoke pollution causes lower infant birthweight, wildfires proved to be a sort of equalizer.

“Wildfires are a meaningful topic to research in and of themselves, but they also help solve this causality problem that is difficult in our studies of pollution,” McCoy said. “Two features make fire pollution different from that of, say, an industrial plant: the random timing of fires and their random location, in that wind patterns on any given day drive the direction and concentration of smoke. This sets up a quasi-experimental research design wherein a fire happens randomly and by chance and randomly and naturally assigns treatment and control groups, because only a certain segment of the population will be exposed to the smoke.”

Several studies have established correlations between pollution sources and negative public health outcomes, McCoy said. However, prior research has faced difficulties demonstrating a direct causal relationship. One reason for this, according to McCoy, is the number of factors that could be involved in past research scenarios.

“Suppose we build an industrial plant,” McCoy said. “Once that plant is built, we need to think about the economics of that problem, which is that people don’t like to live next to plants. Holding everything else constant, home prices will drop in the surrounding area because of that, which could induce geographical sorting, wherein households with lower income might migrate into the areas surrounding the plant and households with higher incomes may leave. When that happens, it becomes harder to determine if changes in health outcomes occurred because of plant pollution, geographical sorting dynamics, or even something else.”

The random timing and location of wildfires mitigate these dynamics, making it ideal for McCoy and Zhao’s research. Wildfire smoke is similar to other sources of ambient air pollution; its particulate matter can be so small that it passes through the heart and lungs, disrupts fetal nutrition, and slows fetal growth. Within this framework, birthweight becomes a useful metric to track because of its link to short-term outcomes, such as one-year mortality rates, as well as long-term outcomes such as educational attainment and earnings, McCoy said.

McCoy and Zhao leveraged geographic information systems (mapping software) to identify ignition sources and smoke paths and plotted the home addresses of infants born during a time that would place them in the smoke’s path while in utero. They then compared the birthweight of those infants to a control group outside of the smoke’s path.

The researchers’ results indicate that wildfire smoke leads to a 4 to 6 percent reduction in birthweight, and these effects are most pronounced among mothers exposed to smoke during the second or the third trimesters of pregnancy. They also found that these effects attenuate (or diminish) with respect to distance to a wildfire, becoming ineffectual three miles and further from the burn source. In contrast, the researchers found that even if infants had been close to a wildfire while in utero, there was no statistically significant effect on their birthweight if they were outside the smoke’s path.

“One really neat thing about this research is that I can do more than tell you what the effect of being exposed to the smoke is or not,” McCoy said. “I can tell you how that effect varies based on where an infant is relative to the source of pollution. Beyond that, we now have the evidence that reinforces earlier findings on the effects of ambient pollution at large and can say that these effects are very likely real, not just loosely correlated or tied up with other economic issues like household migration dynamics.”

McCoy’s hope is that this research will help inform policymakers of the potential economic and health consequences of wildfires, the magnitude of this type of disaster, and the mechanism behind wildfires — all of which enable people to better target the problem.

“There’s a lot of evidence to suggest that homeowners don’t fully acknowledge the risks associated with natural disasters — in particular, the risks associated with wildfire,” McCoy said. “One way to address this problem is to inform the public of risks through information-based regulation, such as posting billboards of people standing on cars during floods to discourage them from attempting to drive through inundated areas in the future. The idea is, if you give people this information, it can affect how they evaluate disaster risks, and it will likely have a spillover effect in terms of how they manage those risks.” That being said, McCoy noted that a one-time exposure to this type of information likely won’t be enough to have a lasting impact, so regulators should share this type of messaging often.

McCoy and Zhao’s research findings have been detailed in their article “Wildfire and Infant Health: A Geo-Spatial Approach to Estimating the Health Impacts of Ambient Air Pollution and In-Utero Stress,” currently under review by a top industry journal.


Source: provided by University of Nevada, Las Vegas (UNLV). Original written by Sara Gorgon. University of Nevada, Las Vegas (UNLV). “Exposure to wildfire smoke in utero lowers birthweight.” ScienceDaily. ScienceDaily, 6 December 2017.

Smoke from Thomas Fire affects air quality in California

Above: Wildfire smoke forecast for 6 p.m. PST December 10, 2017.

(Originally published at 3:30 p.m. PST December 10, 2017)

The Thomas Fire is having a significant effect on the air quality in California. Some areas downwind of the fire to the northwest had “unhealthy” conditions at 2 p.m. Sunday, including Santa Barbara and Goleta. Forecasts show that smoke and ash will continue to affect the southern part of Santa Barbara County for the next several days. The Santa Ynez Valley and the northern parts of the County will see increasing impacts.

Thomas Fire smoke air quality
Satellite photo showing smoke from the Thomas Fire December 10, 2017.
Thomas Fire smoke air quality
Air quality at 2 p.m. PST December 10.
Thomas Fire smoke air quality
Air Quality in Santa Barbara County at 2 p.m. PST December 12, 2017.

Fascinating animation of satellite imagery

What do you find MOST interesting about this video?

Above: screen grab from the NASA video. This image is from August 31, 2017.

NASA’s Goddard Space Flight Center has put together an incredible animation that make it possible to track smoke, dust from Africa, and sea salt. “Sea salt?” you’re thinking? Yes, winds over the oceans pick up salt which becomes visible to sensors on the satellites making it possible to visualize wind patterns, including hurricanes, over the vast expanses of the oceans.

This visualization uses data from NASA satellites, combined with mathematical models in a computer simulation allow scientists to study the physical processes in our atmosphere.

I watched this five times seeing something different with each viewing. So what are you going to watch? Wildfire smoke in Canada? Smoke in Portugal? Smoke in the western U.S.? Smoke in the Southeast? Or dust coming from Africa? Or the wind patterns and hurricanes in the Atlantic? Or the smoke that begins on October 9 northeast of San Francisco generated from the destruction of thousands of homes? Or smoke from fires in Italy?

If you look VERY carefully, you will be able to see a little smoke from something very rare — a wildfire in Greenland, near the coast on the southwest side of the island intermittently between August 2 and 15. (More info about the fire in Greenland.)

I suggest clicking on the full-screen button at the lower right after you start the video. If you’re having trouble viewing it, you can also see it on YouTube.

Report highlights links between wildfires, climate change and health

Pollution from fossil burel-burning sources is decreasing but the air is getting dirtier during the wildland fire season.

As a long and brutal fire season in California starts to wind down, Climate Central issued a report that lays out links between climate change, wildfire, and health effects.  The report, titled Western Wildfires Undermining Progress on Air Pollution, analyzes air quality trends from 2000 through 2016 in two large California air basins — the Sacramento Valley and the San Joaquin Valley — that are heavily affected by pollution. 

The report finds that while the air quality continues to improve as pollution from power plants, trucks and other fossil fuel-burning sources declines, it is getting dirtier during the fire season. Studies have shown that fire seasons in the West are getting longer and that more large wildfires are breaking out as temperatures rise.

“We focused on an especially bad actor called “fine particulate matter”, or PM2.5 — particles that can reach deep into the lungs and exacerbate a wide array of health problems such as asthma, heart disease, and premature birth.  A lot of hard work has been done to decrease PM2.5 from other sources, so it’s troubling to see progress getting undercut by wildfires — and to know that a warming climate will likely have wildfires becoming more frequent and burning more area in California and the West,” said Todd Sanford, Ph.D. scientist with Climate Central.

NBC News: cancer among firefighters

Above: Firefighter working on a smoky wildfire at Buffalo Gap, South Dakota, March 3, 2016.

(Originally published at 10 p.m. MDT October 23, 2017)

This report by NBC News about the rising rates of cancer among firefighters exclusively shows the structural side of the job. Obviously they are exposed to different toxins than their wildland brothers, so it is unknown how much the data crosses over. One of the big differences between the two disciplines is that for structure and vehicle fires a breathing apparatus (BA) is always available. Firefighters on wildland fires NEVER have access to BAs, which only last for minutes, while they can be exposed to smoke for most of their shifts which on large fires are typically up to 16 hours. And wildland firefighters rarely have the opportunity to, as the video recommends, change clothes and shower within an hour after exposure.

In 2010 we began calling for the wildland fire agencies to conduct a study led by medical doctors and epidemiologists to evaluate the short and long term effects of smoke on firefighters. The federal agencies that should take the lead on this are the National Park Service, Bureau of Land Management, Bureau of Indian Affairs, Fish and Wildlife Service, and the Forest Service. State agencies with significant numbers of wildland firefighters need to also be involved.

It is possible that the agencies that employ firefighters do not want to expose the facts about the dangers of smoke. It could cost them money to change their practices, provide a safer workplace, and cover the costs of presumptive illnesses.

Various bills have been introduced in Congress that would establish a cancer registry for firefighters, but to our knowledge none have passed.

Here is an excerpt from an article we wrote March 17, 2017:


“On Wednesday [March 15, 2017] a Montana legislative committee voted down a bill that would have provided benefits for firefighters who developed a lung disease on the job. Republican Mark Noland of Bigfork said firefighters “know what they’re doing”, and:

That is their profession, that is what they chose, and we do not want to, you know, slight them in any way, shape or form, but it is something they’re going into with their eyes wide open.

That is asinine, ridiculous, reprehensible, and irresponsible.

Rep. Mark Noland
Rep. Mark Noland of Bigfork, MT.

He is assuming that when firefighters began their careers they knew there was a good chance they would damage their lungs. If that is common knowledge now, or was 20 years ago when the firefighter signed up, why haven’t the employers already established coverage for presumptive diseases? There is a great deal we do not know about the effects of breathing contaminated air on structure, vehicle, and wildland fires.

Many agencies and government bodies have already established a list of presumptive diseases that will enable health coverage for firefighters. For example the British Columbia government recognizes at least nine “presumptive cancers” among firefighters, including leukemia, testicular cancer, lung cancer, brain cancer, bladder cancer, ureter cancer, colorectal cancer, and non-Hodgkins’s lymphoma.

The Montana legislation would have only covered one of these nine illnesses.

When a person enlists in the military and they come home injured or permanently disabled, should we ignore them, saying they knew what they were getting into? Their “eyes were wide open”? How is treating firefighters injured on the job different? One could argue that they are both defending and protecting our homeland; one of them actually IN our homeland while the other may have been on the other side of the world.” [Update October 23, 2017: for example in an African country, Niger, many Americans have never heard of].


Wildfire smoke maps, October 12, 2017

(Originally published at 7:04 p.m. PDT October 12, 2017)

The map above shows smoke from wildfires in northern California at 5:35 p.m. PDT October 12, 2017.

Below is a forecast for wildfire smoke at 6 p.m. PDT October 13, 2017.

map wildfire smoke forecast
A forecast for wildfire smoke at 6 p.m. PDT October 13, 2017.