Wildfire smoke harms pregnant mothers and babies. Can California cities protect them?

Link redlining, wildfires and premature births

Since the turn of the 20th century, the bulk of affordable housing in Fresno – and, in turn, its low-income populations and many people of color – were located on the west side of the city. Government policies codified housing discrimination in the 1930s with “residential safety maps” that were intended to help investors decide which areas were “safe investments”. They marked “least desirable” neighborhoods in red, which became the basis for the term “redlining”. In many cases, black people living in these demarcated neighborhoods have been denied home loans altogether. West Fresno was one of those neighborhoods in red, and homeowners have been feeling the repercussions ever since.

The idea that today’s health problems can be attributed to redlining is not new, nor is it exclusive to wildfire smoke. In a 2020 study by the UC Berkeley-UC San Francisco Joint Medical Program, researchers found that historically demarcated areas of eight California cities — including Fresno — have “significantly higher rates of emergency room visits due to asthma”. The study analyzed several factors that could contribute to health problems in bounded areas, including emissions from highways, which are more frequently found near low-income neighborhoods. The study also noted briefly that, under racially exclusive housing practices, black families did not have access to well-constructed housing.

A residential safety map of Fresno, created by the Home Owners’ Loan Corporation, in 1936, shows the city’s heritage of redlining. (Image via T-Races Project/University of Maryland)

“Areas that have been demarcated have been shown to have poor quality homes,” says Rachel Sklar, a postdoctoral fellow in the Reproductive Health and Environment Program at UC San Francisco. Sklar is trying to understand the links between redlining and birth complications for pregnant women in California. She explains that because older homes tend to have older windows, poor quality insulation and no air conditioning (requiring residents to open windows), these homes are also likely harboring more air pollution. , including wildfire smoke. This means that residents of these homes could face higher pollution exposure rates.

A 2005 study from the University of California, Berkeley analyzed housing features that can cause air pollution to “leak” into the home. The study found that older, smaller homes tended to leak more than newer, larger homes, which are more likely to have weatherstripping windows and incorporate building techniques. modern. Another study, from 2001, found that there could be a tenfold difference in leakage between homes with the best airtightness and those with the worst.

Air pollution of all types is a problem for these “leaky” homes. But as wildfire smoke increases in both severity and intensity in places like Fresno, public health messaging is failing to address inequities in housing standards. According to a report titled “Wildfire Smoke: A Guide for Public Health Professionals” compiled by the Environmental Protection Agency, “The most common advice during a smoke episode is to stay indoors, where people can better control their environment”. However, the authors explained that the effectiveness of staying indoors as a strategy “depends on how well the building limits smoke coming from inside”. The authors acknowledged that access to air conditioning is helpful in reducing indoor smoke, but many low-income households do not have access to it.

“In highly permeable homes,” the report said, “outdoor particles can easily seep into indoor air, so advice to stay indoors may offer little protection.”

In the summer of 2018, when Pacheco-Werner was pregnant, Fresno County issued a health advisory regarding wildfire smoke and extreme heat. In that advisory, the county advised “people with existing respiratory conditions, young children and the elderly” to “opt out” of smoking. The California Department of Public Health (CDPH) issued similar warnings during the summer months, urging people living near wildfires to “stay indoors if possible.” Although the CDPH advisories indicate that pregnant women like Pacheco-Werner are particularly vulnerable, no alternatives are given to account for variations in indoor air quality or access to filtered air.

Exposure to dangerous levels of wildfire smoke has increased dramatically over the past decade. This is true for most of California and much of the western United States, but Fresno has been hit particularly hard. According to air quality tracking website IQAir: “Smoke moving in from statewide wildfires often reaches the Fresno area and worsens the city’s already poor air quality, often dramatically increasing air pollution levels.”

Researchers are studying the impact of Fresno’s poor air quality on children, including those exposed before birth. The Children’s Health and Air Pollution Study is a collaboration between Stanford University and UC Berkeley that has published numerous studies evaluating the health effects of various sources of air pollution. children, including a 2020 review of the effects of wildfire smoke. The authors cited a single day in 2018 when more than one million school children in California had their classes canceled due to wildfires. Children are particularly sensitive to smoke, they wrote, because they tend to spend more time outdoors, breathe more air relative to their body weight, and continue to grow and develop. Researchers advised improving ventilation and filtration in all buildings where children spend time. They also noted that children’s risk of health problems from wildfire smoke doesn’t just start when they walk to school: problems can arise while they’re still in the womb.

Researchers have recently sought to better understand the effects of wildfire smoke on pregnant women. In 2021, Stanford researchers, led by Sam Heft-Neal, published a study that linked wildfire smoke to premature births across California. Heft-Neal and her team were able to demonstrate that each additional day of smoke exposure was linked to an increased risk of preterm birth, concluding that nearly 7,000 “excess preterm births” in California could be attributed to exposure. to forest fire smoke over the five years of the study. period of the year.

Premature birth is generally defined as birth before 37 weeks of pregnancy. According to the Centers for Disease Control and Prevention, babies born prematurely are at risk for various health complications, including breathing problems, feeding difficulties, vision and hearing problems, and developmental delays. Additionally, a third of infant deaths in the state are related to prematurity.

In the United States, the average rate of premature births is one in 12. But there is a stark racial divide, especially for pregnant women in Fresno County, which is home to the highest rate of premature births in California. At least in part due to social inequality and institutional racism, blacks in Fresno County are nearly 75% more likely to have a preterm birth than whites. This statistic has led researchers, health experts, doctors and community members to launch the California Preterm Birth Initiative to conduct and fund research on racial disparities in birth outcomes while centering the lived experiences of BIPOC. According to the Fresno County Public Health Department, in 2020 the rate of preterm birth among white pregnant women in Fresno County was just under 9%, but the rate among black pregnant women was d about 13.5%. For Hispanic pregnant women, like Tania Pacheco-Werner, it was 10%, although Hispanic premature births make up the highest total number in Fresno County, at 821, reflecting the area’s large Hispanic population. Of the total 1,378 premature births in Fresno County in 2020, 59.5% of them were Hispanic.

Linking preterm birth rates to wildfire smoke exposure is complicated, says Kendalyn Mack-Franklin of the California Preterm Birth Initiative. People of color in Fresno have reported a number of variables that contribute to their high rates of preterm birth, from lack of access to prenatal care to racism within medical facilities. Environmental exposure likely played a role before the significant increase in smoke from wildfires, since Fresno’s red-colored neighborhoods are closer to freeways and polluting industrial areas.

“Premature birth has a lot of confounding variables,” Mack-Franklin says. “It’s very hard to say it’s for a particular reason, unless that reason is racism.”

Bernard P. Love