Fact checked byKristen Dowd

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May 13, 2024
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Coal train pollution linked to more deaths, hospitalizations, asthma

Fact checked byKristen Dowd
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Key takeaways:

  • The train transport of coal yields significant fine particulate matter emissions in dense urban regions.
  • The results indicate important global impacts on economically disadvantaged populations.

Exposure to pollution from passing coal trains led to an increase in the estimated number of deaths, hospitalizations and asthma cases in a San Francisco Bay Area region, according to results published in Environmental Research.

Bart Ostro

“There’s been hundreds of studies relating fine particles (called PM2.5) to adverse health outcomes, and in this study, we quantified what the actual health impacts would be for populations living near rail lines where the coal trains pass by,” Bart Ostro, PhD, epidemiologist with the University of California Davis Air Quality Research Center, told Healio.

Infographic showing number of deaths per year based on average coal train PM2.5 levels.
Data were derived from Ostro B, et al. Environ Res. 2024;doi:10.1016/j.envres.2024.118787.

In this study, Ostro and colleagues evaluated 262,039 individuals residing in the East Bay region of the San Francisco Bay Area, which includes Oakland, Richmond and Berkeley, to determine how PM2.5 from uncovered coal trains impacts various health-related outcomes.

“There were two reasons I was interested in doing this study,” Ostro, former chief of air pollution epidemiology within the California Environmental Protection Agency, said. “First, developers have proposed building a deep-water port in West Oakland in order to export coal to Asia. Second, coal trains transport their product to export terminals and power plants throughout the world, and this issue has not been studied to date. The coal trains would be passing through both the cities of Richmond and Oakland, where vulnerable populations live.”

Ostro noted that the average length of a coal train is a mile and a half, and they usually include 120 cars with no tops.

To determine the contribution of pollution from coal trains vs. freight or passenger trains, Ostro and colleagues used AI.

Researchers then found estimated cases for mortality, hospital admissions, asthma and more by using three different peak annual coal train PM2.5 averages: 0.7 μg/m3, 1 μg/m3 and 2.1 μg/m3.

Within the total cohort followed in the study, there was a high proportion of Hispanic individuals (34.6%), followed by white (26.2%), Black (21.9%), Asian (17%) and Native American and Pacific Islands (0.3%) individuals.

As PM2.5 levels related to coal trains increased, so did the number of deaths, with two deaths per year with a PM2.5 average of 0.7 μg/m3, 2.8 deaths per year with an average of 1 μg/m3 and 5.9 deaths per year with an average of 2.1 μg/m3.

The number of deaths per year in each PM2.5 group was even higher following adjustment for race (0.7 μg/m3, 5.1 deaths; 1 μg/m3, 7.3 deaths; 2.1 μg/m3, 15.2 deaths), according to researchers.

Similar to the above findings, an annual average PM2.5 of 2.1 μg/m3 vs. 1 μg/m3 and 0.7 μg/m3 was linked to more estimated hospital admissions per year for chronic lung disease not including asthma (10.4 vs. 5 vs. 3.5), congestive heart failure (18.8 vs. 9.1 vs. 6.4), pneumonia (17.1 vs. 8.3 vs. 5.9), cardiovascular disease (28 vs. 13.4 vs. 9.4) and stroke (12.2 vs. 5.9 vs. 4.1).

Researchers looked at the number of estimated cases of new asthma in two age groups. In the group between the ages of 0 and 4 years, the number of new asthma cases per year rose as coal train pollution grew (0.7 μg/m3, 4.4; 1 μg/m3, 6.3; 2.1 μg/m3, 13.2). This was also the case in the group between the ages of 5 and 17 years (0.7 μg/m3, 3.1; 1 μg/m3, 4.4; 2.1 μg/m3, 9).

In terms of asthma symptoms, researchers found that a coal train PM2.5 average of 0.7 μg/m3 was linked to an estimated 19,300 days with asthma symptoms, and this number continued to increase with an average of 1 μg/m3 (27,000 days) and 2.1 μg/m3 (57,600 days).

In addition to asthma, researchers observed a heightened number of yearly hay fever/rhinitis cases with coal train pollution (0.7 μg/m3, 45; 1 μg/m3, 64; 2.1 μg/m3, 134).

Another consequence of coal train PM2.5 was lost workdays. Researchers estimated 395 workdays lost when the annual average coal train PM2.5 level was 0.7 μg/m3, which increased to 564 days with an average of 1 μg/m3 and 1,184 days with an average of 2.1 μg/m3.

When divided according to race/ethnicity, the level of PM2.5 was greater among Hispanic vs. white individuals by 41%. Black individuals also faced higher levels of exposure than white individuals by 29%.

“In general, people of color tend to be more vulnerable to the effects of air pollution,” Ostro said. “It’s sort of a double whammy since they have greater exposures because of residential proximity to the coal trains and, per unit of pollution, they seem to have much larger effects than the white population.”

When asked about future studies, Ostro said he is interested in knowing how different environmental and demographic aspects impact the link between coal train pollution and health-related outcomes.

“I would personally like to see additional studies looking at different environments, wind and weather conditions, population densities and the number of vulnerable populations,” he said.

Ostro also emphasized the importance of conducting this study in other areas.
"When you do the studies in your own area, it has a larger impact. People take it more seriously,” he said.

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