OICC Press Anthropogenic Pollution 2588-4646 10 1 2026 06 30 Comparing Trimester to Multi-Year Exposure Windows of Ambient Aerosol and Their Effects on Maternal Blood Biomarkers at Birth 10.57647/AP.2026.1001.01 EN Azizeh Shajravi Department of Environmental Science and Engineering, Isf.C., Islamic Azad University, Isfahan, Iran Atefeh Chamani Department of Environmental Science and Engineering, Isf.C., Islamic Azad University, Isfahan, Iran Soheil Sobhanardakani Department of Environment, Ha.C., Islamic Azad University, Hamedan, Iran Zainab Zamanpour Fertility, Infertility and Perinatology Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Journal Article 2026 06 30 Exposure to ambient aerosols during various lifetime windows may influence maternal blood biomarkers. This study investigates the impact of ambient aerosol exposure during distinct temporal windows (trimester-specific, gestational, and multi-year) on maternal liver biomarkers at delivery in highly polluted regions. Conducted in 2023–2024, the study enrolled 116 pregnant women from Khuzestan Province, Southwest Iran, a region with significant air pollution. Maternal blood samples were collected at birth and analyzed for liver enzymes (ALT: 5- 55 u/L, AST: 9- 51 u/L, ALP: 145- 702 u/L, GGT: 6.7- 99.5 u/L). The MODIS Aerosol Optical Depth (AOD) layers were averaged to create trimester-specific (, , ), gestational (), and 2- and 5-year pre-delivery (, ) aerosol exposure windows for each participant. Employing a multi-modeling approach using a Generalized Additive Model (0.179 < R2 < 0.693), our analysis revealed that biomarkers are more sensitive to AOD levels during mid and late pregnancy compared to those reflecting longer-term exposure. Both urban and regional air quality significantly influenced oxidative stress markers in maternal blood. These findings highlight the liver as susceptible organs to particulate matter-induced oxidative stress and inflammation in highly polluted regions, emphasizing the need for stricter air quality regulations to protect maternal health.