title: Comparisons of ultrafine and fine particles in their associations with biomarkers reflecting physiological pathways.
abstract: Using a quasi-experimental opportunity offered by greatly restricted air pollution emissions during the Beijing Olympics compared to before and after the Olympics, we conducted the current study to compare ultrafine particles (UFPs) and fine particles (PM2.5) in their associations with biomarkers reflecting multiple pathophysiological pathways linking exposure and cardiorespiratory events. Number concentrations of particles (13.0-764.7 nm) and mass concentrations of PM2.5 were measured at two locations within 9 km from the residence and workplace of 125 participating Beijing residents. Each participant was measured 6 times for biomarkers of autonomic function (heart rate, systolic and diastolic blood pressures), hemostasis (von Willebrand factor, soluble CD40 ligand, and P-selectin), pulmonary inflammation and oxidative stress (exhaled nitric oxide and exhaled breath condensate pH, malondialdehyde, and nitrite), and systemic inflammation and oxidative stress (urinary malondialdehyde and 8-hydroxy-2'-deoxyguanosine, plasma fibrinogen, and white blood cells). Linear mixed models were used to estimate associations of biomarkers with UFPs and PM2.5 measured 1-7 days prior to biomarker measurements (lags). We found that the correlation coefficient for UFPs at two locations (∼ 9 km apart) was 0.45, and at the same location, the correlation coefficient for PM2.5 vs UFPs was -0.18. Changes in biomarker levels associated with increases in UFPs and PM2.5 were comparable in magnitude. However, associations of certain biomarkers with UFPs had different lag patterns compared to those with PM2.5, suggesting that the ultrafine size fraction (≤ 100 nm) and the fine size fraction (∼ 100 nm to 2.5 μm) of PM2.5 are likely to affect PM-induced pathophysiological pathways independently.
authors.affiliation: Duke University , Nicholas School of the Environment and Duke Global Health Institute, Durham, North Carolina, United States.
authors.forename: Jicheng
authors.initials: J
authors.lastname: Gong
authors.forename: Tong
authors.initials: T
authors.lastname: Zhu
authors.forename: Howard
authors.initials: H
authors.lastname: Kipen
authors.forename: Guangfa
authors.initials: G
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Hu
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Guo
authors.forename: Pamela
authors.initials: P
authors.lastname: Ohman-Strickland
authors.forename: Shou-En
authors.initials: SE
authors.lastname: Lu
authors.forename: Yuedan
authors.initials: Y
authors.lastname: Wang
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
authors.forename: David Q
authors.initials: DQ
authors.lastname: Rich
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Junfeng
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D015415:Biomarkers / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects*; D002681:China; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008962:Models, Theoretical; D018384:Oxidative Stress; D010316:Particle Size; D052638:Particulate Matter; D011014:Pneumonia / Q000139:chemically induced*; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; D052638:Particulate Matter