# The Exposure Peaks of Traffic-Related Ultrafine Particles Associated with Inflammatory Biomarkers and Blood Lipid Profiles

## TL;DR

The study found that peak exposure to ultrafine particles is linked to changes in inflammation and blood lipid levels, more clearly than annual average exposure.

## Contribution

The study introduces novel metrics for analyzing peak UFP exposure and finds significant associations with inflammatory and lipid biomarkers.

## Key findings

- Increased UFP peak exposure was significantly associated with higher TNF-RII and lower HDL and triglycerides.
- UFP peak exposure was also significantly linked to increased IL-6 and decreased total cholesterol.
- Associations were not significant when using annual average UFP exposure instead of peak metrics.

## Abstract

In this article, we explored the effects of ultrafine particle (UFP) peak exposure on inflammatory biomarkers and blood lipids using two novel metrics—the intensity of peaks and the frequency of peaks. We used data previously collected by the Community Assessment of Freeway Exposure and Health project from participants in the Greater Boston Area. The UFP exposure data were time-activity-adjusted hourly average concentration, estimated using land use regression models based on mobile-monitored ambient concentrations. The outcome data included C-reactive protein, interleukin-6 (IL-6), tumor necrosis factor-alpha receptor 2 (TNF-RII), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides and total cholesterol. For each health indicator, multivariate regression models were used to assess their associations with UFP peaks (N = 364–411). After adjusting for age, sex, body mass index, smoking status and education level, an increase in UFP peak exposure was significantly (p < 0.05) associated with an increase in TNF-RII and a decrease in HDL and triglycerides. Increases in UFP peaks were also significantly associated with increased IL-6 and decreased total cholesterol, while the same associations were not significant when annual average exposure was used. Our work suggests that analysis using peak exposure metrics could reveal more details about the effect of environmental exposures than the annual average metric.