O3 concentration and duration of exposure are factors influencing the environmental health risk of exercising in Rio Grande, Brazil

Determination of major drive of ozone formation and improvement of O3 prediction in typical North China Plain based on interpretable random forest model

O3 pollution in China has become prominent in recent years, and it has become one of the most challenging issues in air pollution control. We used data on atmospheric pollutants and meteorology from 2019 to 2021 to build an interpretable random forest (RF) model, applying this model to predict O3 concentration in 2022 in five cities in the Southwest North China Plain. The model was also used to identify and explain the influence of various factors on O3 formation. The correlation coefficient R2 between the predicted O3 concentration and observed O3 concentration was 0.82, the MAE was 15.15 μg/m3, and the RMSE was 20.29 μg/m3, indicating that the model can effectively predict O3 concentration in the studying area. The results of correlation analysis, feature importance, and the driving factor analysis from SHapley Additive exPlanations (SHAP) model indicated that temperature (T), NO2, and relative humidity (RH) are the top three features affecting O3 prediction, while the weights of wind speed and wind direction were relatively low. Thus, O3 in the southwestern North China Plain may mainly come from the formation of local photochemical activities. The dominant factors behind O3 also varied in different seasons. In spring and autumn, O3 pollution is more likely to occur under high NO2 concentration and high-temperature conditions, while in summer, it is more likely to occur under high-temperature and precipitation-free weather. In winter, NO2 is the dominant factor in O3 formation. Finally, the interpretable RF model is used to predict future O3 concentration based on features provided by Community Multiscale Air Quality (CMAQ) and Weather Research & Forecast (WRF) model, and the simulation performance of CMAQ on O3 concentration is enhanced to a certain extent, improving the prediction of future O3 pollution situations and guiding pollution control.

Exploring the spatial effects and influencing mechanism of ozone concentration in the Yangtze River Delta urban agglomerations of China

Ground-level ozone (O3) pollution has emerged as a significant concern impacting air quality in urban agglomerations, primarily driven by meteorological conditions and social-economic factors. However, previous studies have neglected to comprehensively reveal the spatial distribution and driving mechanism of O3 pollution. Based on the O3 monitoring data of 41 cities in the Yangtze River Delta (YRD) from 2014 to 2021, a comprehensive analysis framework of spatial analysis-spatial econometric regression was constructed to reveal the driving mechanism of O3 pollution. The results revealed the following: (1) O3 concentrations in the YRD exhibited a general increasing and then decreasing trend, indicating an improvement in pollution levels. The areas with higher O3 concentration are mainly the cities concentrated in central and southern Jiangsu, Shanghai, and northern Zhejiang. (2) The change of O3 concentration and distribution is the result of various factors. The effect of urbanization on O3 concentrations followed an inverted U-shaped curve, which implies that achieving higher quality urbanization is essential for effectively controlling urban O3 pollution. Traffic conditions and energy consumption have significant direct positive influences on O3 concentrations and spatial spillover effects. The indirect pollution contribution, considering economic weight, accounted for about 35%. Thus, addressing overall regional energy consumption and implementing traffic source regulations are crucial paths for O3 pollution control in the YRD. (3) Meteorological conditions play a certain role in regulating the O3 concentration. Higher wind speed will promote the diffusion of O3 and increase the O3 concentration in the surrounding city. These findings provide valuable insights for designing effective policies to improve air quality and mitigate ozone pollution in urban agglomeration area.

Effect of particulate matter (PM2.5 and PM10) on health indicators: climate change scenarios in a Brazilian metropolis

Recife is recognized as the 16th most vulnerable city to climate change in the world. In addition, the city has levels of air pollutants above the new limits proposed by the World Health Organization (WHO) in 2021. In this sense, the present study had two main objectives: (1) To evaluate the health (and economic) benefits related to the reduction in mean annual concentrations of PM₁₀ and PM_2.5 considering the new limits recommended by the WHO: 15 µg/m³ (PM₁₀) and 5 µg/m³ (PM_2.5) and (2) To simulate the behavior of these pollutants in scenarios with increased temperature (2 and 4 °C) using machine learning. The averages of PM_2.5 and PM₁₀ were above the limits recommended by the WHO. The scenario simulating the reduction in these pollutants below the new WHO limits would avoid more than 130 deaths and 84 hospital admissions for respiratory or cardiovascular problems. This represents a gain of 15.2 months in life expectancy and a cost of almost 160 million dollars. Regarding the simulated temperature increase, the most conservative (+ 2 °C) and most drastic (+ 4 °C) scenarios predict an increase of approximately 6.5 and 15%, respectively, in the concentrations of PM_2.5 and PM₁₀, with a progressive increase in deaths attributed to air pollution. The study shows that the increase in temperature will have impacts on air particulate matter and health outcomes. Climate change mitigation and pollution control policies must be implemented for meeting new WHO air quality standards which may have health benefits.

The role of O3 exposure and physical activity status on redox state, inflammation, and pulmonary toxicity of young men: A cross-sectional study

The exposure to traffic-related air pollutants, such as NO₂ and O₃, are associated with detrimental health effects, becoming one of the greatest public health issues worldwide. Exercising in polluted environments could result in harmful outcomes for health and may blunt the physiological adaptations of exercise training. This study aimed to investigate the influence of physical activity and O₃ exposure on redox status, an inflammatory marker, response to stress, and pulmonary toxicity of healthy young individuals. We performed a cross-sectional study with 100 individuals that, based on their exposure to O₃ and physical fitness (PF) level, were distributed in four groups: Low PF + Low O₃; Low PF + High O₃; High PF + Low O₃; High PF + High O₃. We evaluated personal exposure to NO₂ and O_3, physical activity level, variables of oxidative stress (SOD, ROS, CAT, GSH, TBARS), pulmonary toxicity (CC16), and inflammatory mediators (IL-1β, IL-4, IL-6, IL-10, TNF-α, HSP70). Spearman correlation test to check the association among the variables was used and to compare groups we used one-way ANOVA followed by Bonferroni's post hoc and Kruskal Wallis test followed by Dunn's post hoc. O₃ levels correlated with physical activity (r = 0.25; p = 0.01) but not with age or markers of body composition (p > 0.05). The individuals with high physical fitness that were less exposed to O₃ presented higher CAT activity (p < 0.001), lower TBARS (p < 0.01) and IL-1β concentrations (p < 0.01), higher IL-6 (p < 0.05) and IL-10 concentrations (p < 0.05), lower IL-6:1L-10 ratio (p < 0.05), lower CC16 levels (p < 0.05), and higher HSP70 concentration (p < 0.05). Physical activity could result in higher exposure to O₃ that could partially blunt some exercise adaptations, while high physical fitness improved the antioxidant defense system, systemic inflammatory mediators, and pulmonary toxicity.

Weekend effect of air pollutants in small and medium-sized cities: The role of policies stringency to COVID-19 containment

Although the pattern of air pollutants has been extensively studied during the COVID-19 pandemic, the weekend effect has been rarely investigated. In order to understand the impact of policies stringency as well as the interruption-recovery pattern, the aim of the study was to investigate the levels of air pollutants (O3, NO2, SO2, PM2.5, PM10) and PM2.5/PM10 ratio before and after the COVID-19 pandemic in four cities in the state of Rio Grande do Sul, Brazil, evaluating the weekend effect at these two scenarios and also identifying how the restriction measures applied locally had an impact on this effect. For this, daily data from two years of monitoring of air pollutants were collected and the weekend effect was calculated based on the levels from Monday to Friday (weekday) and Saturday and Sunday (weekend). There was a positive weekend effect for almost all criteria air pollutants in the four cities, and an intrinsic relation between the weekend effect and the restriction measures adopted. A negative weekend effect was observed in the scenario characterized by less restrictive and more permissive policies for daily and occupational activities. Conversely, when more stringent measures were implemented, this trend was reversed and higher intensities of positive weekend effect were observed as restrictions increased. In conclusion, the COVID-19 perturbation to air quality changed as regions tighten and loosen restrictions on human mobility. These insights that can guide responsible authorities about future strategies and policies for air quality control.

Exposure to O3 and NO2 in physically active adults: an evaluation of physiological parameters and health risk assessment

The gaseous air pollutants ozone (O₃) and nitrogen dioxide (NO₂) have a large public health relevance and trigger environmental health risk. On the other hand, despite the health benefits, exercise practices might increase the susceptibility to air pollutants exposure. However, there are innumerous lifestyle factors besides physical activity habits that must be considered in the daily air pollution exposure and are still not fully comprehended. This study aimed to evaluate the effects of O₃ and NO₂ exposure on cardiorespiratory fitness, lipid accumulation product (LAP), and environmental health risk during the entire daily routine of physically active adults that exercise in outdoor and indoor environments. One hundred and twenty healthy young men were assigned to untrained (n = 52), indoor exercise (n = 36), and outdoor exercise (n = 32) groups, following their lifestyle exercise habits, and O₃ and NO₂ were assessed by personal monitoring. Exercised groups demonstrated higher healthy eating index (HEI) (p < 0.001), physical activity (PA) (p < 0.001), metabolic equivalent of task (MET) (p < 0.001), and peak oxygen uptake VO_2peak (p < 0.001), while outdoor group had lower LAP index (p < 0.001) and higher O₃ concentration (p = 0.0442). Environmental health risk demonstrated no difference (p > 0.05). The higher O₃ concentration was positively correlated with the risk quotient (p = 0.003) and MET (p = 0.020), and a negative correlation between LAP and VO_2peak was observed (p < 0.001). In conclusion, physically active individuals might have a lower risk of developing cardiovascular and metabolic diseases despite the higher O₃ concentration exposure, and the exposure during exercise did not represent an additional health risk.

Weekend effect on air pollutant levels in southernmost cities of Brazil with different economic activities

In view of the current premises of the need to investigate air pollution in small- and medium-sized cities, combined with concerns regarding the weekly behavior of air pollutants, this study aimed to investigate the weekly pattern of air pollution (O₃, NO₂, SO₂, PM_2.5) and the weekend effect in 4 Brazilian cities with different main economic activities. Our main findings include (1) positive weekend effect for all the assessed air pollutants in the four cities; therefore, in the southernmost region of Brazil, there was an increase in the concentration of air pollutants during weekends when compared to weekdays; (2) the highest levels of NO₂ and SO₂ were observed in the city characterized by the economic activity revolving around coal mining and generation of electricity through the burning of this mineraloid in a coal-fired power plant, while the highest levels of PM_2.5 were in the city with economic activity linked to industries, due to its recognized industrial complex; and (3) the seasonal evaluation of the weekend effect showed different behaviors for the air pollutants in each location, which is related to the set of meteorological conditions, economic activities, and population mobility in each location. In conclusion, our results demonstrate the aspects of pollution between cities and highlight that the comprehensive understanding of the weekend effect and its intricacies allows the responsible personal and government authorities to gain deep insights into the true effectiveness of future control strategies and the development of possible action plans.

Association of air pollution exposure with exercise-induced oxygen desaturation in COPD

BACKGROUND

There is a link between exposure to air pollution and the increased prevalence of chronic obstructive pulmonary disease (COPD) and declining pulmonary function, but the association with O₂ desaturation during exercise in COPD patients with emphysema is unclear. Our aims were to estimate the prevalence of O₂ desaturation during exercise in patients with COPD, and determine the association of exposure to air pollution with exercise-induced desaturation (EID), the degree of emphysema, and dynamic hyperinflation (DH).

METHODS

We assessed the effects of 10-year prior to the HRCT assessment and 7 days prior to the six-minute walking test exposure to particulate matter with an aerodynamic diameter of < 10 µm (PM₁₀) or of < 2.5 µM (PM_2.5), nitrogen dioxide (NO₂), and ozone (O₃) in patients with emphysema in this retrospective cohort study. EID was defined as a nadir standard pulse oximetry (SpO₂) level of < 90% or a delta (△)SpO₂ level of ≥ 4%. Ambient air pollutant (PM_2.5, PM₁₀, O₃, and NO₂) data were obtained from Taiwan Environmental Protection Administration (EPA) air-monitoring stations, usually within 10 km to each participant's home address.

RESULTS

We recruited 141 subjects with emphysema. 41.1% of patients with emphysema exhibited EID, and patients with EID had more dyspnea, worse lung function, more severe emphysema, more frequent acute exacerbations, managed a shorter walking distance, had DH, and greater long-term exposure to air pollution than those without EID. We observed that levels of 10-year concentrations of PM₁₀, PM_2.5, and NO₂ were significantly associated with EID, PM₁₀ and PM_2.5 were associated with the severity of emphysema, and associated with DH in patients with emphysema. In contrast, short-term exposure did not have any effect on patients.

CONCLUSION

Long-term exposure to ambient PM₁₀, PM_2.5 and NO₂, but not O₃, was associated with EID.