Indoor air pollution from solid fuels use, inflammation, depression and cognitive function in middle-aged and older Chinese adults

Air pollution is linked to cognitive decline independent of hypersensitive C-reactive protein: insights from middle-aged and older Chinese

BACKGROUND

Long-term air pollution exposure and inflammation are considered to be associated with cognitive decline. However, whether air pollution exposure related cognitive decline is dependent on inflammation remains uncertain.

MATERIALS AND METHODS

The present study collected data from China Health and Retirement Longitudinal Study (CHARLS) at baseline in 2011, with a follow up period in 2015. Concentration of air pollutants (particles with diameters ≤ 1.0 μm [PM1], ≤ 2.5 μm [PM2.5], ≤ 10 μm [PM10], nitrogen dioxide [NO2] and ozone [O3]) were obtained from China High Air Pollutants (CHAP) dataset. Hypersensitive C-reactive protein (hs-CRP), a systemic inflammation marker, was measured in blood of subjects and cognitive function was assessed by standardized questionnaire.

RESULTS

A total of 6434 participants were included in the study. Lower exposure to PM2.5, PM1, PM10 and NO2 were associated with mitigated cognitive decline. The odds ratios (ORs) for air pollutants changes and cognitive decline and 95% confidence intervals (CIs) were as follows: PM2.5-0.934(0.925, 0.943), PM1- 0.945 (0.935,0.955), PM10-0.977(0.972,0.982) and NO2-0.962(0.950,0.975), respectively. Hs-CRP showed no significant correlation with cognitive decline or change in levels of air pollution. The interaction regression analyses, both unadjusted and adjusted, did not uncover any significant correlation between hs-CRP and air pollution with respect to cognitive decline. Bootstrap test exhibited no significant mediating effect of hs-CRP on the relationship between any air pollutants and cognitive decline, the indirect effects of hs-CRP in conjunction with exposure to different air pollutants were all found to be non-significant, with the following bootstrap CIs and p-values: PM2.5-1.000([1.000,1.000], P = 0.480),PM1-1.000([1.000,1.000], P = 0.230),PM10-1.000([1.000,1.000], P = 0.650), O3-1.000([1.000,1.000], P = 0.470), ΔNO2-1.000([1.000,1.000], P = 0.830) .

CONCLUSION

Ambient air pollution exposure was linked to cognitive decline independent of hs-CRP level.

Indoor air pollution by solid fuel usages for cooking is longitudinally associated with possible sarcopenia in middle-aged Chinese population

Objectives

The Asia Working Group of Sarcopenia (AWGS) 2019 consensus proposed a new concept named "possible sarcopenia". The present study was to estimate the association between indoor air pollution by solid fuel usages for cooking and possible sarcopenia among middle-aged and older Chinese population.

Methods

A longitudinal cohort analysis was carried out using nationally representative data from the China Health and Retirement Longitudinal Study (CHARLS). A total of 17,708 participants were recruited and followed up in the CHARLS. Cox proportional hazards models were used to estimate the effects of cooking fuel usages on the new onset of possible sarcopenia. Stratified analyses were performed according to gender and age, and sensitivity analyses were performed using the complete dataset.

Results

A total of 4,653 participants were included in the final cohort analysis. During the follow-up of 4 years (2011-2015), a total of 1,532 (32.92%) participants developed new-onset possible sarcopenia. Compared with clean fuel usages for cooking, solid fuel usages were associated with a higher risk of possible sarcopenia (HR = 1.37, 95% CI = 1.23-1.52, p-value < 0.001). After adjusting for potential confounders, there was a trend for association between solid fuel usages and an increased risk of possible sarcopenia. Stratified analyses by gender and age demonstrated a stronger association of the solid fuel usages with possible sarcopenia in the middle-aged female participants (Model 1: HR = 1.83, 95% CI = 1.24-2.69, p-value = 0.002; Model 2: HR = 1.65, 95% CI = 1.10-2.47, p-value = 0.016). Sensitivity analyses indicated that the results were robust.

Conclusion

Indoor air pollution from solid fuel usages for cooking was a modifiable risk factor for sarcopenia, especially in middle-aged female population. These findings provide a new prevention strategy to reduce the growing burden of sarcopenia, especially for middle-aged female individuals using solid fuels for cooking.

Switching indoor fuels and the incidence of physical-psychological-cognitive multimorbidity: A prospective cohort study

BACKGROUND

In developing countries, including China, solid-fuel-based heating and cooking is common. For older people, the multimorbidity prevalence is exceptionally high. Nevertheless, studies on the associations of indoor solid fuels use, especially switching fuels types, on multimorbidity in middle-aged and older people is scarce.

METHODS

Data from five waves of the China Health and Retirement Longitudinal Study were used in this study. Indoor fuels were classified as solid or clean fuels. Physical-psychological-cognitive multimorbidity (PPC-multimorbidity) was defined as the simultaneous presence of three disease types (physical illness, psychological disorders, cognitive impairment). Using Cox proportional risk models, hazard ratios (HRs) and 95 % confidence intervals (95 % CI) were calculated to investigate the associations of heating- and cooking-related baseline indoor fuels and switching indoor fuels with PPC-multimorbidity incidence.

RESULTS

In the heating (n=3121, mean age=56.55 years, male proportion=54.25 %) and cooking (n=3574, mean age=56.67 years, male proportion=52.94 %) analyses, 75.07 % and 45.64 % of the participants used solid fuels at baseline, and 564 (18.07 %) and 613 (17.15 %) PPC-multimorbidity cases were diagnosed during follow-up, respectively. Participants with baseline heating- and cooking-based solid fuels use had greater PPC-multimorbidity incidences [HRs (95 % CIs): 1.23 (0.98, 1.55) and 1.44 (1.21, 1.73)], respectively. Additionally, combined baseline heating- and cooking-based solid fuels use was associated with even greater PPC-multimorbidity incidence [HR (95 % CI): 1.55 (1.18, 2.04)]. Persistent solid fuels use obviously increased the PPC-multimorbidity incidence [HRs (95 % CIs): 2.43 (1.67, 3.55) for heating and 2.63 (2.03, 3.40) for cooking]. Moreover, switching from solid to clean fuels was associated with a significantly decreased PPC-multimorbidity incidence [HRs (95 % CIs): 0.27 (0.20, 0.35) for heating and 0.36 (0.28, 0.46) for cooking].

CONCLUSIONS

Long-term solid-fuels use is associated with an increased PPC-multimorbidity incidence, and switching to cleaner fuels is associated with a decreased PPC-multimorbidity incidence in adults aged ≥45 years.

Association between household air pollution due to unclean fuel use and depression among older adults in India: A cross-sectional study

Background

Depression is a major public concern among older adults. However, limited studies have examined the association of depression and household air pollution (HAP). Therefore, this study examines the association between HAP due to unclean fuel use and depression among older adults in India.

Methods

Data from Longitudinal Aging Study of India (LASI), wave-1 (2017-18) were used (N = 50,206, ≥50 years). Depression measured by CIDI-SF (Composite International Diagnostic Interview-Short Form) was the outcome variable. Household unclean fuel use was considered as proxy of HAP. Bivariate analyses and multivariate logistic regression were used to fulfil the study objectives.

Results

The prevalence of depression was greater among unclean fuel users than clean fuel users (9.6% vs 6.6%). Results showed that household unclean fuel use was associated with higher odds of depression. The interaction analyses showed that females and rural residents were at higher risk of depression due to HAP exposure. Furthermore, household cooking conditions also played an important role in the association between HAP exposure and depression. Unclean fuel use indoors without ventilation and with traditional chullah/stove was associated with higher odds of depression among older adults.

Conclusion

The study concludes that exposure to HAP due to unclean fuel use should be considered as a potential risk factor of depression among older adults. Therefore, the study suggests an urgent need to create awareness about negative effects of unclean fuel use on mental health and promote clean fuel usage in households to ensure healthy aging.

Risk assessment of unclean cooking energy usage from the perspective of subjective wellbeing: The mediating role of perceived physical and mental health

Although outdoor air pollution has been associated with adverse health outcomes and decreased subjective welfare, there has been a lack of research investigating the potential risks associated with indoor unclean cooking energy usage from the perspective of subjective wellbeing. This paper systematically assesses the risks of unclean cooking fuel usage from the novel perspective of subjective welfare and examines the mediating role of perceived physical and mental health applying a large-scale nationally representative dataset. Analytical results demonstrate that the usage of unclean cooking energy has significantly negative impacts on subjective wellbeing, and this finding has been confirmed through various robustness tests. The mechanism behind this impact is that unclean cooking fuel usage reduces people's perceived physical and mental health status, which in turn decreases their subjective wellness. Furthermore, the negative consequences of using unclean cooking energy on subjective wellbeing are particularly pronounced among certain demographic groups, including older, lower educated, married individuals as well as those with lower economic status, uncovered by medical insurance and having less social capital. Findings of this study highlight the risks linked to unclean cooking energy usage, as evidenced in the negative impact on perceived health and subjective wellbeing. In light of the increasing focus on improving indoor environment as well as enhancing people's health and wellbeing, results of this paper emphasize the significance of promoting access to cleaner and healthier energy.

Population attributable fractions of cancer mortality related to indoor air pollution, animal contact, and water source as environmental risk factors: Findings from the Golestan Cohort Study

BACKGROUND

Environmental risk factors are significant contributors to cancer mortality, which are neglected.

PURPOSE

This study aimed to estimate the population attributable fraction of cancer mortality due to the environmental risk factors.

METHODS

Golestan cohort study is a population-base cohort on 50045 participants between 40-75 with about 18 years of follow up. We detected 2,196 cancer mortality and applied a multiple Cox model to compute the hazard ratio of environmental risk factor on all cancer and cancer-specific mortality. The population attributable fraction was calculated, accordingly.

RESULTS

Biomass fuels for cooking, as an indoor air pollution, increased the risk of colorectal, esophageal, gastric cancer, and all-cancer mortality by 84%, 66%, 37%, and 17% respectively. Using gas for cooking, particularly in rural areas, could save 6% [Population Attributable Fraction: 6.36(95%CI: 1.82, 10.70)] of esophageal cancer, 3% [Population Attributable Fraction: 3.43 (0, 7.33)] of gastric cancer, and 6% [Population Attributable Fraction: 6.25 (1.76, 13.63)] of colorectal cancer mortality. Using a healthy tap water source could save 5% [Population Attributable Fraction:5.50(0, 10.93)] of esophageal cancer mortality, particularly in rural areas. There was no significant association between indoor air pollution for heating purposes and animal contact with cancer mortality.

CONCLUSION

Considering the results of this study, eliminating solid fuel for most daily usage, among the population with specific cancer types, is required to successfully reduce cancer related mortality. Adopting appropriate strategies and interventions by policymakers such as educating the population, allocating resources for improving the healthy environment of the community, and cancer screening policies among susceptible populations could reduce cancer related mortalities.

Relationship of solid fuels use with cognitive function and efficacy of switching to cleaner fuels or using ventilation: A systematic review and meta-analysis

BACKGROUND

A growing number of studies have examined the relation between solid fuels use and cognitive function in the mid-elderly, but results are inconsistent. Therefore, a systematic review and meta-analysis was carried out to evaluate their relevance and the efficacy of switching to cleaner fuels or using ventilation.

METHOD

We used PubMed, Web of Science, and Cochrane Library databases to identify 17 studies in which the primary outcome variable was cognitive function decline or cognitive disorders, and the exposure measure was solid fuels use. The final search date of August 31, 2023. The effect size of odds ratio (OR), regression coefficient (β), and 95% confidence interval (CI) were pooled. Heterogeneity and the possibility of publication bias were assessed by using the Q-statistic and Begg's test, respectively.

RESULT

Among the 17 included papers, the study participants were ≥45 years old. Eleven studies assessed the relationship between solid fuels use and cognitive function decline [number of studies (n) = 11, β = -0.144; I2 = 97.7%]. Five studies assessed the relationship between solid fuels use and cognitive disorders (n = 5, OR = 1.229; I2 = 41.1%). Switching from using solid fuels to clean fuels could reduce the risk of cognitive function decline as compared to those who remained on using solid fuels (n = 2; β = 0.710; I2 = 82.4%). Among participants using solid fuels, who cooked without on ventilated stoves were correlated with an enhanced risk of cognitive disorders as compared to participants who cooked with ventilated stoves (n = 2; OR = 1.358; I2 = 44.7%).

CONCLUSION

Our meta-analysis showed a negative relationship between solid fuels use with cognitive function, and a positive relationship with cognitive disorders. Cleaner fuels, using ventilation, improved cookstoves can reduce the adverse health hazards of solid fuels use.

Impact of indoor air pollution from cooking fuel usage and practices on self-reported health among older adults in India: Evidence from LASI

This research aims to explore the impact of various components of Indoor air pollution (IAP) on the Self-Reported Health (SRH) of older adults in India. Using a sample of 27,090 from the Longitudinal Aging Study in India (LASI) Wave-1, a multiple binary logistic regression model was employed to identify specific risk factors associated with poor SRH among older adults. Adjusting for demographic, socioeconomic, and IAP-related components, it was revealed that IAP significantly contributes to poor SRH. The adjusted model indicated that individuals using solid cooking fuels face a higher risk of poor SRH compared to those using liquid fuels. Additionally, individuals not using electric chimneys and cooking near windows are associated with an elevated risk of poor SRH, highlighting the importance of adequate ventilation. Health risk factors, including lung disease, diabetes, cough, and depression, further contribute to poor SRH among older adults exposed to IAP. Overall, the study offers crucial insights for policymakers, healthcare professionals, and environmentalists to improve the well-being of the vulnerable older population in India.

The association between indoor air pollution from solid fuels and cognitive impairment: a systematic review and meta-analysis

This study aimed to comprehensively and methodically evaluate the correlation between cognitive impairment and indoor air pollution from solid fuel used for cooking/heating. PubMed, Web of Science, EMBASE, and Cochrane Library databases were searched up to December January 2023. 13 studies from three countries with a total of 277,001 participants were enrolled. A negative correlation was discovered between solid fuel usage for cooking and total cognitive score (β=-0.73, 95 % CI: -0.90 to -0.55) and episodic memory score (β=-0.23, 95 % CI: -0.30 to -0.17). Household solid fuel usage for cooking was considerably associated with a raised risk of cognitive impairment (HR=1.31, 95 % CI: 1.09-1.57) and cognitive decline (HR=1.24, 95 % CI: 1.18-1.30). Compared to continuous solid fuel use for cooking, sustained use of clean fuel and switching from solid fuel to clean fuel were associated with a lower risk of cognitive decline (OR=0.55, 95 % CI: 0.42-0.73; OR=0.81, 95 % CI: 0.71-0.93). A negative association was found between solid fuel usage for heating and total cognitive score (β=-0.43, 95 % CI: -0.59 to -0.26) and episodic memory score (β=-0.22, 95 % CI: -0.34 to -0.10). Our research provided evidence that exposure to indoor air pollution from solid fuel is a potential cause of cognitive impairment and cognitive decline. Making the switch from solid fuels to cleaner fuels could be an important step in preventing cognitive impairment in the elderly.

Household polluting cooking fuels and intrinsic capacity among older population: A harmonized nationwide analysis in India and China

BACKGROUNDS

Household polluting cooking fuels, as an important changeable behavior, are related to various detrimental health effects among the elderly. There is limited research on the association between polluting cooking fuel use and intrinsic capacity (IC) as an indicator of healthy aging. This study aimed to evaluate the above-mentioned association in India and China, where polluting cooking fuel use is common.

METHODS

We enrolled 33,803 participants aged ≥60 years from two nationally representative studies: the Longitudinal Aging Study in India and the China Health and Retirement Longitudinal Study. Polluting cooking fuel use was defined as a self-report of using wood, coal, kerosene, crop residue, or dung. IC was measured by five aspects, including locomotion, cognition, vitality, sensory, and psychological capacity. The random-effects mixed linear regression and logistic regression with population weighting were performed. Multivariable-adjusted model and propensity score were used to adjust for potential confounders.

RESULTS

A total of 47.54 % and 59.32 % of elderly adults reported primary cooking using polluting fuels in India and China, respectively. Using polluting cooking fuels was consistently associated with IC decline; particularly, cognitive capacity was the most susceptible domain. In India, participants using polluting fuels had a 1.062 (95 % confidence interval [CI]: 1.047-1.078) times risk for IC deficits, whereas more prominent results were observed in China (odds ratio [OR]: 2.040, 95 % CI: 1.642-2.533). Such harmful effects might be alleviated by transferring from polluting to clean fuels. Additionally, the duration of polluting fuel use was also positively associated with IC deficits.

CONCLUSION

This study provided substantial public implications on healthy aging for the elderly population at a global scale, strengthening the importance of health education and policy efforts to accelerate the transition from polluting to clean fuels.

Volatile organic compounds exposure associated with depression among U.S. adults: Results from NHANES 2011-2020

Volatile organic compounds (VOCs) are important contributors to air pollution. VOCs exposure was associated with various human diseases. Depression is one of the most prevalent mental disorders and poses a serious mental health burden. Although VOCs are neurotoxic and can damage the central nervous system, the association between VOCs exposure and depression remains obscure. Based on data from the National Health and Nutrition Examination Survey, we included 5676 adult individuals and 15 major components of urinary volatile organic compound metabolites (mVOCs). We comprehensively evaluated the potential association between each single urinary mVOC exposure and depressive symptoms using binary logistic and restricted cubic spline regression, whereas the weighted quantile sum regression and least absolute shrinkage and selection operator regression model were used to explore the mixture co-exposure association. The results indicated significantly higher mean concentrations of the 11 urinary mVOC components in the depression group than that in the non-depression group. And 12 mVOC components had a significantly positive association with depression. The overall effect of all 15 mVOCs components was also significantly positive. The corresponding odds ratio was 1.56 (95%CI: 1.2-2.03) in the categorical variable model and the regression coefficient was 0.36 (95%CI: 0.12-0.6) in the numerical variable model. Five urinary mVOCs (URXCYM, URXPHG, URX34 M, URXMB3, and URXAMC) were identified as the most relevant components associated with depression, with 89.06% total weights in the categorical variable model and 89.39% in the numerical variable model. The mVOCs were the biomarkers of VOCs, their concentrations in urine could specifically represent the contents of their metabolic parents in the human body. Considering that the metabolic parents of the above five mVOCs were predominantly acrylonitrile, toluene, styrene, acrylamide, 1,3-Butadiene, and xylenes, our results further indicated that exposure to these VOCs was closely related to depression, and more attention should be paid to the mental health risks of VOCs exposure.

Unveiling the link between systemic inflammation markers and cognitive performance among older adults in the US: A population-based study using NHANES 2011-2014 data

PURPOSE

This study aimed to evaluate the association between systemic inflammation markers and cognitive performance among older US adults.

METHODS

This cross-sectional study assessed 3,632 older participants from the 2011-2014 National Health and Nutrition Examination Survey (NHANES). The main analysis included participants aged over 60 years. Systemic inflammation markers were quantified by calculating the composite inflammation indicators from the blood routine count, and cognitive performance was assessed using Consortium to Establish a Registry for Alzheimer's Disease (CERAD) test, Animal Fluency test (AFT), and Digit Symbol Substitution test (DSST).

RESULTS

There were 2,743 individuals enrolled in the current analysis. The overall mean age was 64.9 years and 48.7 % were males. The levels of SIRI and PIV were significant negative associated with scores of CERAD, CERAD delayed recall, and DSST in the unadjusted models. Moreover, SII were significant negative associated with scores of CERAD and CERAD delayed recall. After adjusting the covariates of demographics, lifestyle factors, history of chronic diseases and BMI, significant negative association were observed between systematic inflammation markers and cognitive performance. Additionally, a progressive and significant decrease in the score of cognitive performance assessments with the increased levels of SIRI, SII, and PIV were respectively observed. Finally, the correlation between systemic inflammation markers and cognitive performance were evidenced in the sensitive analysis.

CONCLUSION

Findings support a strong inverse correlation between systemic inflammation markers and cognitive performance, suggesting that addressing inflammation could be a promising avenue for enhancing cognitive health and mitigating age-related cognitive decline.

Multidimensional Internet Use, Social Participation, and Depression Among Middle-Aged and Elderly Chinese Individuals: Nationwide Cross-Sectional Study

BACKGROUND

There is growing evidence that the internet has beneficial effects on the mental health of middle-aged and older people (≥45 years), but the evidence is inconclusive, and the underlying mechanisms are less known.

OBJECTIVE

This study aims to explore the relationship between multidimensional (devices, frequency, and purpose) internet use and depression in middle-aged and elderly Chinese, as well as the mediating effect of social participation. Moreover, this study will explore the moderating effect of the regional informatization development level (RIDL) on the relationships between individual internet use, social participation, and depression.

METHODS

Data on 17,676 participants aged 45 years or older were obtained from the China Health and Retirement Longitudinal Study (CHARLS) 2018 data set. The 10-item Center for Epidemiologic Studies Depression Scale (CES-D-10) was used to identify the presence of depression. Logistic regression was used to explore the relationship between each dimension of internet use and depression. Multiple linear regression was used to explore the mediating effect of social participation and the moderating effect of the RIDL.

RESULTS

The results showed that 28.33% (5008/17,676) of the total population had depression. In terms of regional subgroups, respondents living in the western region exhibited the highest proportion of depression (2041/5884, 34.69%). Internet use was negatively associated with depression (odds ratio 0.613, 95% CI 0.542-0.692; P<.001). Various dimensions of internet use positively contributed to individual social participation and reduced individual depression (devices: β=-.170, 95% CI -0.209 to -0.127; frequency: β=-.065, 95% CI -0.081 to -0.047; and purpose: β=-.043, 95% CI -0.053 to -0.031). In addition, the RIDL weakened the relationship between individual-level internet use and social participation (internet use: F74.12,9.82=7.55, P<.001; devices: F51.65/9.88=5.23, P=.005; frequency: F66.74/10.08=6.62, P=.001; and purpose: F66.52/9.78=6.80, P=.001), and negatively moderated the relationship between the frequency of internet use and depression (frequency: F662.67/188.79=3.51, P=.03).

CONCLUSIONS

This study found that different dimensions of internet use are associated with lower levels of depression. Social participation partially mediates the association between multidimensional internet use and depression in the eastern, central, and western regions, respectively. Additionally, the RIDL helps individuals further their internet use and social participation, reducing the impact of depression. However, this effect weakens sequentially from the western region to the central region and then to the eastern region.

Method Development for Detecting Low Level Volatile Organic Compounds (VOCs) among Workers and Residents from a Carpentry Work Shop in a Palestinian Village

Volatile organic compounds (VOCs) are considered a major public health concern in industrial location areas. The presence of exposure to (VOCs) has raised concern regarding the health effects caused by chronic human exposure as this will increase cancer diseases in the village. An analytical method has been developed and modified to help us detect 38 VOCs in the blood of 38 volunteers who are related to a carpentry shop at the parts-per-trillion level. To measure and evaluate the potential risk, several devices, such as portable passive monitors and air-collected samples, in addition to blood concentration, were used to study three different occupational groups. Ten of the volunteers are employees at the shop, 10 volunteers live very close to the shop, and 10 of them are students in an elementary school very close to the shop. In this study, we developed an automated analytical method using headspace (HS) together with solid-phase microextraction (SPME) connected to capillary gas chromatography (GC) equipped with quadrupole mass spectrometry (MS). The detection limits for the method used were measured in the range from 0.001 to 0.15 ng/L, using linear calibration curves that have three orders of magnitude. The detected concentrations ranged from 3 ng L^-1 for trichloroethene to 91 ng L^-1 for toluene and 270 ng L^-1 for 2,4-diisocyanate, which was derived from the paint solvents used for the wood in the carpentry shop and the paints on the walls. More than half of all assessed species (80%) had mean concentration values less than 50 ng L^-1, which is the maximum allowed for most VOCs. The major chemical types among the compounds quantified will be those we found in our previous study in the surrounding air of a carpentry workshop in Deir Ballout in Palestine, which were toluene diisocyanate and butyl cyanate. Some were found to be highly present air. Most of the measurements were below the guidelines of the World Health Organization (WHO). Despite the fact that this study only involved a small number of smokers, smoking was found to be connected with several blood and breath components. This group includes unsaturated hydrocarbons (1,3-butadiene, 1,3-pentadiene, 2-butene), furans (2,5-dimethylfuran), and acetonitrile. The proposed classification of measured species into systemic (blood-borne) and exogenous volatiles is strictly hypothetical, as some species may have several origins.

Monitoring and apportioning sources of indoor air quality using low-cost particulate matter sensors

Air quality is one of the most important factors in public health. While outdoor air quality is widely studied, the indoor environment has been less scrutinised, even though time spent indoors is typically much greater than outdoors. The emergence of low-cost sensors can help assess indoor air quality. This study provides a new methodology, utilizing low-cost sensors and source apportionment techniques, to understand the relative importance of indoor and outdoor air pollution sources upon indoor air quality. The methodology is tested with three sensors placed in different rooms inside an exemplar house (bedroom, kitchen and office) and one outdoors. When the family was present, the bedroom had the highest average concentrations for PM_2.5 and PM₁₀ (3.9 ± 6.8 ug/m³ and 9.6 ± 12.7 μg/m³ respectively), due to the activities undertaken there and the presence of softer furniture and carpeting. The kitchen, while presenting the lowest PM concentrations for both size ranges (2.8 ± 5.9 ug/m³ and 4.2 ± 6.9 μg/m³ respectively), presented the highest PM spikes, especially during cooking times. Increased ventilation in the office resulted in the highest PM₁ concentration (1.6 ± 1.9 μg/m³), highlighting the strong effect of infiltration of outdoor air for the smallest particles. Source apportionment, via positive matrix factorisation (PMF), showed that up to 95 % of the PM₁ was found to be of outdoor sources in all the rooms. This effect was reduced as particle size increased, with outdoor sources contributing >65 % of the PM_2.5, and up to 50 % of the PM₁₀, depending on the room studied. The new approach to elucidate the contributions of different sources to total indoor air pollution exposure, described in this paper, is easily scalable and translatable to different indoor locations.

The Relationship between Ambient Fine Particulate Matter (PM2.5) Pollution and Depression: An Analysis of Data from 185 Countries

Several studies have identified a relationship between air pollution and depression, particularly in relation to fine particulate matter (PM2.5) exposure. However, the strength of this association appears to be moderated by variables such as age, gender, genetic vulnerability, physical activity, and climatic conditions, and has not been assessed at a cross-national level to date. Moreover, certain studies in this field have yielded negative results, and there are discrepancies between the results obtained in high-income countries and those from low- and middle-income countries. The current study examines cross-sectional and longitudinal associations between the incidence of depression in each country, based on Global Burden of Disease Study data, and the average national level of PM2.5 based on the World Health Organization’s database, over the past decade (2010–2019). The observed associations were adjusted for age, gender, level of physical activity, income, education, population density, climate, and type of depression. It was observed that while PM2.5 levels showed significant cross-sectional associations with the incidence of depression, longitudinal analyses were not suggestive of a direct causal relationship. These findings are discussed in the light of recent contradictory results in this field, and the need to consider the intermediate roles of a number of individual and environmental factors.

Oxidative Stress in Depression: The Link with the Stress Response, Neuroinflammation, Serotonin, Neurogenesis and Synaptic Plasticity

Depression is a prevalent, complex, and highly debilitating disease. The full comprehension of this disease is still a global challenge. Indeed, relapse, recurrency, and therapeutic resistance are serious challenges in the fight against depression. Nevertheless, abnormal functioning of the stress response, inflammatory processes, neurotransmission, neurogenesis, and synaptic plasticity are known to underlie the pathophysiology of this mental disorder. The role of oxidative stress in disease and, particularly, in depression is widely recognized, being important for both its onset and development. Indeed, excessive generation of reactive oxygen species and lack of efficient antioxidant response trigger processes such as inflammation, neurodegeneration, and neuronal death. Keeping in mind the importance of a detailed study about cellular and molecular mechanisms that are present in depression, this review focuses on the link between oxidative stress and the stress response, neuroinflammation, serotonergic pathways, neurogenesis, and synaptic plasticity's imbalances present in depression. The study of these mechanisms is important to lead to a new era of treatment and knowledge about this highly complex disease.