Indoor Air Pollution: Ozone Byproducts Linked to Changes in Red Blood Cell Production
A new study reveals that ozone, a common indoor air pollutant, doesn’t just irritate lungs-it transforms everyday oils into compounds that can alter red blood cell production. Published in ACS ES&T Air in July 2025 (DOI: 10.1021/acsestair.5c00369),the research sheds light on the previously poorly understood health impacts of these airborne pollutants.
Researchers are increasingly focused on the health consequences of poor indoor air quality, especially for vulnerable populations. This latest work, part of a broader effort to understand these effects, couples air quality measurements wiht health data from study participants. The interdisciplinary research began at Xizang University in Lhasa,China,with researchers inviting Yingjun Liu,an associate professor at Peking University,to analyze indoor air samples.
The unique location of Xizang University-situated on the Tibetan plateau-provided an ideal setting for the study. While Lhasa boasts remarkably clean outdoor air, especially regarding fine particulate matter (PM2.5), residents experience elevated outdoor ozone levels due to the altitude.This allowed the team to isolate the effects of ozone byproducts, controlling for the confounding factor of PM2.5. “lhasa is one of the cleanest cities [in China] in terms of outdoor air quality, especially PM2.5,” Liu explained.
To gather data, researchers recruited just over 100 university students for two field campaigns, each lasting approximately one month. Participants underwent four health checks, including blood draws, while researchers simultaneously collected indoor air samples using sorbent tubes placed in the students’ dorm rooms. These samples were then analyzed with mass spectrometry to determine the concentration of various longer-chain carbonyl species, such as hexanol, octanol, and decanal. A graduate researcher is pictured installing a sorbent tube on a bedpost at Xizang University to collect an indoor air sample.
“it is rare to see a study that performs rigorous chemical sampling (speciating individual carbonyls) while simultaneously collecting clinical blood data from a human cohort,” noted Nijing Wang, an atmospheric chemist at the Max Planck Institute for Chemistry, who was not involved in the research. Traditionally, studies have relied on measuring ozone loss as an indicator of these byproducts.
The analysis revealed that while the measured carbonyls weren’t correlated with arterial stiffness, vascular tone, acute cardiac function, or hypoxia, they were linked to changes in red blood cell indices, including red blood cell count and hemoglobin level. Specifically, decanal-a carbonyl formed when ozone reacts with skin oil-showed the strongest impact on red blood cells.
According to Liu, increased decanal concentrations correlated with increased red blood cell indices. “For the short term, it might increase your oxygen carrying capacity, but in the long term, it’s going to increase the viscosity of your blood,” she cautioned, highlighting the potential for long-term health consequences.
While these findings represent a step toward understanding the health effects of ozonolysis products, researchers acknowledge the need for further examination.Bingying Zhao, a graduate researcher at the University of British Columbia, pointed out that the unique living surroundings of the Tibetan university students may not be representative of broader populations. “Their response to carbonyls might be more magnified, or perhaps the students are actually less sensitive to these carbonyls because their ability to adapt to [stressful] environments,” Zhao speculated.
Future research will require interdisciplinary collaboration to determine how diverse populations respond to indoor carbonyls and to elucidate the underlying biological mechanisms driving the observed changes in red blood cell indices. As Wang emphasized, “The field cannot rely solely on chemists measuring air or epidemiologists measuring people; we need studies that combine both.”
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