Impacts of In-Cabin Exposure to Size-Fractionated Particulate Matters and Carbon Monoxide on Changes in Heart Rate Variability for Healthy Public Transit Commuters

Abstract

To evaluate the cardiovascular impact of traffic-related pollutant exposure on healthy young adults, the research team has collected the primary data of in-cabin exposure to air pollutants and heart rate variability (HRV). Twenty young healthy college students were recruited in Taipei metropolitan area. In addition to electrocardiogram, personal exposure to air pollutants, i.e., particulate matter (PM) and carbon monoxide (CO), and weather conditions, including temperature and relative humidity (RH), on campus, bus, and mass rapid transit were monitored continuously. The following HRV parameters were evaluated using generalized additive mixed model to adjust for personal and meteorological variables: heart rate (HR), the square root of the mean of the sum of the squares of differences between adjacent normal-to-normal (NN) intervals (r-MSSD), the standard deviation of all NN intervals (SDNN), the percentage of successive NN interval differences greater than 50 ms (pNN50), low-frequency power (LF), high-frequency power (HF), total power (TP), and LF/HF. They were assessed to find out the association between in-cabin exposure and HRV parameters. Compared with the HRV parameters measured on campus, the percent changes in r-MSSD, SDNN, pNN50+1, LF, HF, and TP decreased when the participants were in public transits. After adjusting for all locations, 5 min moving averages of PM2.5–10 and PM1 were significantly associated with the increase in the percent changes in HR and SDNN. Additionally, 5 min moving averages of PM2.5–10 exposure were significantly associated with the decrease in the percent change in HF, while it was significantly associated with the increase of the percent change in LF/HF. The reduction of the percent change in HR was also found to be significantly associated with 5 min CO moving averages. To conclude, current analyses have shown that size-fractionated PMs and CO exposure in public transits might lead to significant changes of HRV parameters for healthy young adults.

Twelve-Year Analysis of NO2 Concentration Measurements at Belisario Station (Quito, Ecuador) Using Statistical Inference Techniques

“…Nonparametric statistical inference tools have also been used in the analysis of air pollution variables [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. This has been important, because if the data do not follow parametric distributions, then classical statistical inference is unfounded, which is the case of study in this research.…”

“…This has been important, because if the data do not follow parametric distributions, then classical statistical inference is unfounded, which is the case of study in this research. In this sense, in [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] nonparametric analysis tools have been used to study several variables of air pollution. Nevertheless, nonparametric analysis is much more sensitive to the influence of extreme values than robust analysis.…”

“…Finally, it is important to mention that nonparametric statistical methods have also been used to estimate the behavior of air pollution variables [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. However, the results obtained using nonparametric methods are inferior to those obtained using robust methods, in the sense that robust methods are practically immune to the influence of extreme values.…”

Robust Estimation of Carbon Monoxide Measurements

“…With the purpose of conducting the above-mentioned study, nonparametric tests such as the Kruskal-Wallis test and the Mann-Whitney U test [ 20 , 21 ] were used [ 19 ]. Other examples of recent publications in which nonparametric tests have been used to analyze measurements of air pollution variables can be found in [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ].…”

Nanoparticle Behaviour in an Urban Street Canyon at Different Heights and Implications on Indoor Respiratory Doses

“…Particulate matter (PM) is one of the most relevant air pollutants, linked to the pathogenesis of several human diseases involving numerous systems and apparatuses. In particular, many studies highlighted that some specific PM fractions (particles diameter ≤ 10 µm and ≤ 2.5 µm, defined respectively as PM 10 and PM 2.5 ) were associated to cardiovascular, respiratory and neurodegenerative diseases [2][3][4]. In addition, in 2015 PM in outdoor air was classified as a Group 1 carcinogen to humans by the International Agency for Research on Cancer (IARC) [5].…”