Particulate Matter Of Aerodynamic Diameter Research Articles

Nighttime Outdoor Artificial Light and Risk of Age-Related Macular Degeneration

Light pollution's impact on human health is increasingly recognized, but its link to exudative age-related macular degeneration (EAMD) remains unclear. To investigate the association between exposure to outdoor artificial light at night (OALAN) and the risk of incident EAMD. In this nationwide population-based case-control study, all individuals 50 years or older with newly diagnosed EAMD between January 1, 2010, and December 31, 2011, were identified with reference to the Korean National Health Insurance Service registration program database for rare and intractable diseases. Birth year- and sex-matched controls (with no EAMD diagnosis until 2020) were selected at a 1:30 ratio. Data were acquired from May 1 to December 31, 2021, and analyzed from June 1 to November 30, 2022. Mean levels of OALAN at participants' residential addresses during 2008 and 2009 were estimated using time-varying satellite data for a composite view of persistent nighttime illumination at an approximate scale of 1 km2. The hazard ratios (HRs) and 95% CIs of the association between residential OALAN and risk of incident EAMD were determined based on maximum likelihood estimation after adjusting for sociodemographic characteristics, comorbidities, and area-level risk factors (ie, nighttime traffic noise and particulate matter of aerodynamic diameter ≤10 μm in each participant's administrative district of residence). A total of 126 418 participants were included in the analysis (mean [SD] age, 66.0 [7.9] years; 78 244 men [61.9%]). Of these, 4078 were patients with newly diagnosed EAMD and 122 340 were EAMD-free matched controls. In fully adjusted models, an IQR (55.8 nW/cm2/sr) increase in OALAN level was associated with an HR of 1.67 (95% CI, 1.56-1.78) for incident EAMD. The exposure-response curve demonstrated a nonlinear, concave upward slope becoming more pronounced at higher levels of light exposure (ie, at approximately 110 nW/cm2/sr). In a subgroup analysis, an IQR increase in OALAN was associated with increased risk of incident EAMD in urban areas (HR, 1.46 [95% CI, 1.33-1.61]) but not in rural areas (HR, 1.01 [95% CI, 0.84-1.22]). In this nationwide population-based case-control study, higher levels of residential OALAN were associated with an increased risk of incident EAMD. Future studies with more detailed information on exposure, individual adaptive behaviors, and potential mediators are warranted.

Associations between air pollution exposure and empirically derived subtypes of mild cognitive impairment in older women

AbstractBackgroundExposure to air pollution in older adulthood is a novel risk factor for mild cognitive impairment (MCI). MCI is a heterogenous construct with different subtypes likely reflecting different disease etiologies. Understanding if long‐term exposure to air pollution is differentially associated with MCI subtypes may provide insight into the neurotoxic effects of air pollution exposure on the aging brain.MethodParticipants included women from the Women’s Health Initiative Memory Study. Data from 651 women without dementia who screened positive for cognitive impairment on the modified mini‐mental state examination (3MS) and a randomly selected comparison sample of 2,560 women who were cognitively intact based on the 3MS were utilized. Participants were administered the 3MS annually (1996‐2008). Those who screened positive for cognitive impairment on the 3MS completed the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) cognitive battery and the Trailmaking Test parts A and B. Average annual levels of particulate matter of aerodynamic diameter<2.5 (PM2.5) and nitrogen dioxide (NO2) were estimated at the participant’s residence using regionalized national universal kriging models and averaged over the 3‐year period before the cognitive assessment. Latent class structural equation models (SEM) were constructed to identify MCI subtypes. We then examined associations between air pollution exposure and latent class membership using multinomial regression while adjusting for demographic, lifestyle, and clinical confounders.ResultFour significant MCI subtypes were identified (Figure 1): multidomain MCI (n = 147; 23%), amnestic MCI (n = 141; 22%), dysnomic/dysexecutive MCI (n = 200; 31%), and subtle MCI (n = 163; 25%). Women living in locations with higher levels of PM2.5 (per interquartile range [IQR] = 3.93 µg/m3; OR = 1.28; p = .04) or NO2 (per IQR = 9.25 ppb; OR = 1.36; p = .02) were more likely to be classified as having subtle MCI compared to normal comparisons. One IQR increase in NO2 was also associated with increased likelihood of being classified with dysnomic/dysexecutive MCI (OR = 1.38; p = .003) compared to normal comparisons.ConclusionOur study illustrates that long‐term exposure to PM2.5 and NO2 may be associated with specific subtypes of MCI. Our findings provide further evidence that air pollution may exert neurotoxic effects on brain areas underlying executive function and language ability in older women.

Prenatal air pollution, fetal β-cell dysfunction and neurodevelopmental delay

BackgroundEmerging evidence has reported significant associations of prenatal air pollution exposure with neurodevelopmental delay in offspring. Sensitive exposure windows and the modifiable factor remain elusive. ObjectiveWe aim to identify sensitive windows of air pollution during pregnancy on neurodevelopmental delay, and examine whether cord blood C-peptide mediates the relationship. MethodsThis study included 7438 mother-newborn pairs in Hefei, China, from 2015 to 2021. Weekly exposure to particulate matter of aerodynamic diameter <2.5 µm, 10 µm (PM2.5, PM10), nitrogen dioxide (NO2) and carbon monoxide (CO) was estimated at regulatory air monitoring stations in Hefei. Denver Developmental Screening Test-II and the Gesell Developmental Schedules were applied to assess the neurodevelopmental delay in children 6–36 mon of age. Distributed lag nonlinear models examined sensitive time windows of prenatal air pollutants exposure. Mediation analysis estimated the mediating role of cord blood C-peptide. ResultsThe sensitive PM2.5, PM10, NO2, and CO exposure windows associated with neurodevelopmental delay were throughout pregnancy. Weekly air pollutants exposure was related to higher neurodevelopmental delay risks [cumulative odds ratio (OR): 1.40(1.29,1.53) in PM2.5 (per 10 μg/m3), 1.40(1.28,1.53) in PM10 (per 10 μg/m3), 1.41(1.30,1.52) in CO (per 0.1 mg/m3), and 1.49(1.29,1.72) in NO2 (per 5 μg/m3)]. Mediation analysis indicated 18.3 % contributions of cord C-peptide to the relationship [average mediation effect: 0.04(0.01.0.06); average direct effect: 0.15(0.07.0.25)]. Conclusions: Exposure to air pollution throughout pregnancy is linked to neurodevelopmental delay mediated by poorer fetal β-cell function. Screening and treatment of abnormal glucose metabolism in infants could benefit the prevention of air pollution-associated neurodevelopment delay.

Air quality, meteorological variability and pediatric respiratory syncytial virus infections in Singapore

Respiratory syncytial virus (RSV) is an important cause of respiratory illness among children. While studies have focused on the air-quality and climate dependence of RSV infections, few have been undertaken in South-East Asia where the burden of respiratory illness is among the highest across the globe. This study aimed to determine the relationships between climatic factors and air quality with RSV infections among children in Singapore. We obtained all laboratory-confirmed reports of RSV infections in children below 5 years old from the largest public hospital specializing in pediatric healthcare in Singapore. We assessed the independent cumulative effects of air quality and meteorological factors on RSV infection risk using the Distributed Lag Non-Linear Model (DLNM) framework in negative binomial models adjusted for long-term trend, seasonality and changes in the diagnostic systems. We included 15,715 laboratory-confirmed RSV reports from 2009 to 2019. Daily maximum temperature exhibited a complex, non-linear association with RSV infections. Absolute humidity (Relative Risk, 90th percentile [RR90th percentile]: 1.170, 95% CI: [1.102, 1.242]) was positively associated with RSV risk. Higher levels of particulate matter of aerodynamic diameter of less than (i) 2.5 µm (PM2.5), (ii) 10 µm (PM10), carbon monoxide (CO) and sulfur dioxide (SO2) were associated with lower RSV infection risk. RSV infections exhibited both annual and within-year seasonality. Our findings suggest that falls in ambient temperature and rises in absolute humidity exacerbated pediatric RSV infection risk while increases in air pollutant concentrations were associated with lowered infection risk. These meteorological factors, together with the predictable seasonality of RSV infections, can inform the timing of mitigation measures aimed at reducing transmission.

Indoor air quality and the risk of hypertension.

Indoor air quality and the risk of hypertension.

Oxidative Stress and Antioxidant Response in Populations of the Czech Republic Exposed to Various Levels of Environmental Pollutants.

We aimed to identify the variables that modify levels of oxidatively damaged DNA and lipid peroxidation in subjects living in diverse localities of the Czech Republic (a rural area, a metropolitan locality, and an industrial region). The sampling of a total of 126 policemen was conducted twice in two sampling seasons. Personal characteristics, concentrations of particulate matter of aerodynamic diameter <2.5 µm and benzo[a]pyrene in the ambient air, activities of antioxidant mechanisms (superoxide dismutase, catalase, glutathione peroxidase, and antioxidant capacity), levels of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), concentrations of persistent organic pollutants in blood plasma, and urinary levels of polycyclic aromatic hydrocarbon metabolites were investigated as parameters potentially affecting the markers of DNA oxidation (8-oxo-7,8-dihydro-2′-deoxyguanosine) and lipid peroxidation (15-F2t-isoprostane). The levels of oxidative stress markers mostly differed between the localities in the individual sampling seasons. Multivariate linear regression analysis revealed IL-6, a pro-inflammatory cytokine, as a factor with the most pronounced effects on oxidative stress parameters. The role of other variables, including environmental pollutants, was minor. In conclusion, our study showed that oxidative damage to macromolecules was affected by processes related to inflammation; however, we did not identify a specific environmental factor responsible for the pro-inflammatory response in the organism.

Daily Associations of Air Pollution and Pediatric Asthma Risk Using the Biomedical REAI-Time Health Evaluation (BREATHE) Kit.

Background: Exposure to air pollution is associated with acute pediatric asthma exacerbations, including reduced lung function, rescue medication usage, and increased symptoms; however, most studies are limited in investigating longitudinal changes in these acute effects. This study aims to investigate the effects of daily air pollution exposure on acute pediatric asthma exacerbation risk using a repeated-measures design. Methods: We conducted a panel study of 40 children aged 8–16 years with moderate-to-severe asthma. We deployed the Biomedical REAI-Time Health Evaluation (BREATHE) Kit developed in the Los Angeles PRISMS Center to continuously monitor personal exposure to particulate matter of aerodynamic diameter < 2.5 µm (PM2.5), relative humidity and temperature, geolocation (GPS), and asthma outcomes including lung function, medication use, and symptoms for 14 days. Hourly ambient (PM2.5, nitrogen dioxide (NO2), ozone (O3)) and traffic-related (nitrogen oxides (NOx) and PM2.5) air pollution exposures were modeled based on location. We used mixed-effects models to examine the association of same day and lagged (up to 2 days) exposures with daily changes in % predicted forced expiratory volume in 1 s (FEV1) and % predicted peak expiratory flow (PEF), count of rescue inhaler puffs, and symptoms. Results: Participants were on average 12.0 years old (range: 8.4–16.8) with mean (SD) morning %predicted FEV1 of 67.9% (17.3%) and PEF of 69.1% (18.4%) and 1.4 (3.5) puffs per day of rescue inhaler use. Participants reported chest tightness, wheeze, trouble breathing, and cough symptoms on 36.4%, 17.5%, 32.3%, and 42.9%, respectively (n = 217 person-days). One SD increase in previous day O3 exposure was associated with reduced morning (beta [95% CI]: −4.11 [−6.86, −1.36]), evening (−2.65 [−5.19, −0.10]) and daily average %predicted FEV1 (−3.45 [−6.42, −0.47]). Daily (lag 0) exposure to traffic-related PM2.5 exposure was associated with reduced morning %predicted PEF (−3.97 [−7.69, −0.26]) and greater odds of “feeling scared of trouble breathing” symptom (odds ratio [95% CI]: 1.83 [1.03, 3.24]). Exposure to ambient O3, NOx, and NO was significantly associated with increased rescue inhaler use (rate ratio [95% CI]: O3 1.52 [1.02, 2.27], NOx 1.61 [1.23, 2.11], NO 1.80 [1.37, 2.35]). Conclusions: We found significant associations of air pollution exposure with lung function, rescue inhaler use, and “feeling scared of trouble breathing.” Our study demonstrates the potential of informatics and wearable sensor technologies at collecting highly resolved, contextual, and personal exposure data for understanding acute pediatric asthma triggers.

Ambient Air Pollution and Increasing Depressive Symptoms in Older Women: The Mediating Role of The Prefrontal Cortex

Exposure to air pollution may accelerate brain aging and increase risk of late-life depressive symptoms (DS). Brain structures underlying these associations are unknown. Longitudinal data from 829 community-dwelling women without dementia (baseline age 81.6 ± 3.6 years old) who participated in both the Women’s Health Initiative Memory Study Magnetic Resonance Imaging study (WHIMS-MRI; 2005-06) and the WHIMS-Epidemiology of Cognitive Health Outcomes (2008-16) were analyzed to examine whether volumetric measures of brain structures mediated associations between long-term exposure to ambient air pollutants and annual increases in DS (as measured by annually assessed 15-item Geriatric Depression Scale). Annual PM2.5 (fine particulate matter of aerodynamic diameter <2.5) and NO2 were estimated at the participants’ residence using regionalized universal kriging models and aggregated to the 3-year average prior to the WHIMS-MRI. Structural equation models were constructed to estimate associations between exposure, structural brain variables, and trajectories of DS (standardized on baseline mean and SD). Living in locations with higher NO2 (standardized β = 0.023; 95% Confidence Interval (CI) = 0.004, 0.042) or PM2.5 (standardized β = 0.021; 95% CI = 0.004, 0.038) was associated with larger annual increases in DS (~60% larger annual increase in DS). Higher NO2, but not PM2.5, was associated with smaller prefrontal cortical volumes (standardized β = -0.431; 99% CI = -0.518; -0.344). Prefrontal cortical volume explained 30.4% of the total association between annual DS increase and NO2. These findings underscore the importance of the prefrontal cortex in associations between NO2 exposure and increasing DS in later-life.

Air Quality Improvement Is Associated With Decreasing Depressive Symptoms in Older Women

Air pollution exposure is an environmental risk factor in brain aging and may also be associated with late-life depressive symptoms (DS). It is unknown if air quality (AQ) improvement is associated with reductions in DS in later life. Longitudinal data from 917 cognitively intact women with no prior history of depression (baseline age 66.4 ± 1.6 years old) participating in the Women’s Health Initiative Memory Study of Younger Women (WHIMSY; 2008-2016) were analyzed to examine whether AQ improvement over the 5-years prior to WHIMSY baseline was associated with trajectories of DS (measured by 15-item Geriatric Depression Scale). Annual PM2.5 (fine particulate matter of aerodynamic diameter <2.5) and NO2 were estimated at the participants’ residence using regionalized universal kriging models. Estimates were aggregated to the 3-year average at 5 years (remote) and immediately (recent) before WHIMSY baseline. Associations between AQ improvement (difference between remote to recent exposure) and trajectories of DS were estimated using linear mixed effect models, adjusting for sociodemographic, lifestyle, and clinical covariates. AQ improved prior to baseline (PM2.5: 1.62 ± 1.45 μg/m3 and NO2: 3.70 ± 2.81 ppb). Women residing in locations with greater improvement in NO2 (per IQR = 4.34 ppb) or PM2.5 (per IQR = 2.30 μg/m3) reported significant annual reductions in DS (βNO2=3.1%, p=.046; βPM25=1.6%, p=.046), similar to the effect of engaging in moderate to vigorous physical activity four times or more a week. These findings suggest that improving air quality may reduce depressive symptoms in older women.

Associations Between Air Pollution Exposure and Empirically Derived Profiles of Cognitive Performance in Older Women.

Elucidating associations between exposures to ambient air pollutants and profiles of cognitive performance may provide insight into neurotoxic effects on the aging brain. We examined associations between empirically derived profiles of cognitive performance and residential concentrations of particulate matter of aerodynamic diameter < 2.5 (PM2.5) and nitrogen dioxide (NO2) in older women. Women (N = 2,142) from the Women's Health Initiative Study of Cognitive Aging completed a neuropsychological assessment measuring attention, visuospatial, language, and episodic memory abilities. Average yearly concentrations of PM2.5 and NO2 were estimated at the participant's addresses for the 3 years prior to the assessment. Latent profile structural equation models identified subgroups of women exhibiting similar profiles across tests. Multinomial regressions examined associations between exposures and latent profile classification, controlling for covariates. Five latent profiles were identified: low performance across multiple domains (poor multi-domain; n = 282;13%), relatively poor verbal episodic memory (poor memory; n = 216; 10%), average performance across all domains (average multi-domain; n = 974; 45%), superior memory (n = 381; 18%), and superior attention (n = 332; 15%). Using women with average cognitive ability as the referent, higher PM2.5 (per interquartile range [IQR] = 3.64μg/m3) was associated with greater odds of being classified in the poor memory (OR = 1.29; 95% Confidence Interval [CI] = 1.10-1.52) or superior attention (OR = 1.30; 95% CI = 1.10-1.53) profiles. NO2 (per IQR = 9.86 ppb) was associated with higher odds of being classified in the poor memory (OR = 1.38; 95% CI = 1.17-1.63) and lower odds of being classified with superior memory (OR = 0.81; 95% CI = 0.67-0.97). Exposure to PM2.5 and NO2 are associated with patterns of cognitive performance characterized by worse verbal episodic memory relative to performance in other domains.

Associations between air pollution exposure and subtypes of cognitive performance in older women

AbstractBackgroundAir pollution exposure is a novel environmental risk factor in brain aging. It remains unclear whether long‐term exposure in older adulthood is associated with profiles of cognitive performance across multiple domains.MethodParticipants included 2,185 women (aged 66‐83 years) without dementia from the Women’s Health Initiative Study of Cognitive Aging. Baseline neuropsychological assessment included tests of verbal episodic memory (California Verbal Learning Test), figural memory (Benton’s Visual Recognition Test), language (letter and category fluency), attention (Digit Span Forward and Backwards), and visuospatial ability (Card Rotations Test). Testes were adjusted for demographic age, education, and race/ethnicity. Average annual levels of particulate matter of aerodynamic diameter&lt;2.5 (PM2.5) and nitrogen dioxide (NO2) were estimated at the participant’s residence using regionalized national universal kriging models and averaged over the 3‐year period before the baseline assessment. Latent class structural equation models (SEM) were constructed to identify latent classes of women who had similar patterns of performance across cognitive tests. After identifying the number of latent classes extract in the model, we constructed a second SEM to examine associations between air pollution exposure and latent class membership using multinomial regression while adjusting for demographic, lifestyle, and clinical confounders.ResultFive significant latent classes were identified (Figure 1): multidomain cognitive impairment (n=247; 11%), amnestic cognitive impairment (n=263; 12%), superior memory (n=407; 19%), superior attention (n=351; 16%), and average cognitive ability (n=917; 42%). Women living in locations with higher levels of PM2.5 (per interquartile range [IQR] = 3.63 μg/m3) or NO2 (per IQR = 10.33) were more likely to be classified as having amnestic cognitive impairment compared to having average cognitive ability (OR=1.27; p=.021). One IQR increase in NO2 was also associated with decreased likelihood of having superior memory (OR=.81; p=.024) compared to average cognitive ability.ConclusionOur cross‐sectional study illustrates that long‐term exposure to PM2.5 and NO2 may be associated with specific patterns of cognitive performance; mainly worse episodic memory relative to performance in other domains. Our findings provide further evidence that air pollution may exert neurotoxic effects on brain areas underlying episodic memory in older women.

Cumulative exposure amount of PM2.5 in the ambient air is associated with coronary atherosclerosis - Serial coronary CT angiography study

BackgroundWe investigated the change of coronary atherosclerosis with long-term exposure to fine particulate matter of aerodynamic diameter <2.5 ​μm (PM2.5) using coronary computed tomography angiography (CCTA). MethodsSubjects undergoing serial CCTAs between January 2007 and December 2017 (n ​= ​3,127) were analyzed. Each individual's cumulative amount of PM2.5 exposure between the two CCTAs was evaluated by Kriging interpolation and zonal analysis, considering the time interval between the two CCTAs. The main outcome was progression of coronary artery calcium (CAC) with additional semiquantitative analysis on the changes in the severity and composition of atherosclerotic plaques. ResultsThe CAC scores increased by 30.8 Agatston units per-year under a median PM2.5 concentration 24.9 ​μg/m3 and tended to increase with the cumulative amount of PM2.5 exposure (r ​= ​0.321, p ​<0.001). The CAC progressed in 1,361 (43.5%) subjects during a median 53 months follow-up. The cumulative amount of PM2.5 exposure was independently associated with CAC progression (adjusted OR 1.09, p ​<0.001). By random forest analysis, the relative impact of cumulative amount of PM2.5 exposure on CAC progression was higher than that of traditional cardiovascular risk factors and the average concentration of PM2.5. The extent of coronary atherosclerosis and newly developed calcified plaque on follow-up were also significantly associated with the cumulative amount of PM2.5 exposure. ConclusionsCumulative exposure to air pollution is associated with the progression of diffuse coronary calcification, the importance of which may be more significant than other traditional cardiovascular risk factors. Further investigations into the causality between PM2.5 and coronary atherosclerosis are warranted to improve global cardiovascular health.

Prenatal exposure to air pollution and neurodevelopmental delay in children: A birth cohort study in Foshan, China

BackgroundPrenatal exposure to air pollution may have adverse effects on neurodevelopment in children, but epidemiological evidence remains inconclusive. ObjectiveTo investigate the associations between prenatal air pollution exposure and neurodevelopmental delay. MethodsWe conducted a birth cohort study based on pregnancy and birth registry in Foshan, China. Exposure to particulate matter of aerodynamic diameter < 1 μm, 2.5 μm, 10 μm (PM1, PM2.5, PM10), nitrogen dioxide (NO2) and sulfur dioxide (SO2) over pregnancy (trimester 1, 2, 3 and entire pregnancy) was estimated at each woman's residential address using spatial-temporal models. Neurodevelopmental assessment was performed by pediatricians using a five-domain scale and developmental quotient (DQ) was calculated as a global measure. Logistic regression models were used to investigate the associations between prenatal air pollution exposure and neurodevelopmental delay (DQ < 75) with adjustment for potential confounders. ResultsWe included 15,778 child-mother pairs in this analysis, including 1013 children with neurodevelopmental delay. We observed positive associations between prenatal exposure to air pollution and higher risk of neurodevelopmental delay in children. The adjusted odds ratios (ORs) per 10 μg/m3 elevation in PM1, PM2.5, PM10, NO2 and SO2 in entire pregnancy were 1.12 [95% confidence interval (CI): 1.01, 1.25], 1.15 (95% CI: 1.03, 1.29), 1.12 (95% CI: 1.02, 1.24), 1.06 (95% CI: 0.94, 1.19) and 1.58 (95% CI: 1.11, 2.23), respectively. The associations were more robust for trimester 1 and trimester 2, especially trimester 1. ConclusionsExposure to air pollution during pregnancy, especially early-to-mid pregnancy, was associated with increased risk of neurodevelopmental delay in young children, indicating its adverse neurodevelopmental effects in early-life stage.

Ambient air pollution and cardiorespiratory outcomes amongst adults residing in four informal settlements in the Western Province of South Africa

BACKGROUND AND AIM: Despite the majority of ambient air pollution-related deaths occurring in low-and middle-income countries, most of the studies that have investigated the relationship between ambient air pollution and cardiorespiratory outcomes were not conducted in Africa. This study investigated the relationship between ambient air pollution exposure and self-reported cardiorespiratory outcomes amongst adults residing in four informal settlements of the Western Province of South Africa. METHODS: A cross-sectional study comprising of 572 adults from four informal settlements (Khayelitsha, Marconi-Beam, Oudtshoorn and Masiphumelele) in Western Cape, South Africa was conducted. The study made use of modelled exposure estimates using Land-Use Regression for particulate matter of aerodynamic diameter of 2.5µm (PM2.5) and nitrogen dioxide (NO2) at each participant’s home address. An adapted European Community Respiratory Health Survey and National Health and Nutrition Examination Survey questionnaire was used to collect data on self-reported cardiorespiratory outcomes and covariates. RESULTS:The median age of the participants was 40.7 years and 88.5% of the participants were female. The median NO2 level was 19.7 µg/m3 with interquartile range (IQR): 9.64 – 23.7 and PM2.5 level, 9.7 µg/m3 (IQR: 7.3 – 12.4). An interquartile range increase of 5.12 µg/m3 in PM2.5 was associated with an increase prevalence of self-reported chest-pain [1.38 (95%CI: 1.06 - 1.80)] adjusting for NO2, and other covariates. CONCLUSIONS:The study found preliminary evidence of a possible association between annual ambient PM2.5 exposure and chest-pain (a crude proxy of angina-related pain), even at levels below both WHO Air Quality Guidelines and the South African National Ambient Air Quality Standards. However, the results should be interpreted cautiously due to the self-reported nature of the outcome measure, small sample size and the cross-sectional design of the study. KEYWORDS: Air Pollution, Cardiovascular Diseases, Respiratory Diseases, Chemical Exposures, Asthma

Health Risk Analysis of Elemental Components of an Industrially Emitted Respirable Particulate Matter in an Urban Area.

Particulate matter of aerodynamic diameter of less than 2.5 µm (PM2.5) is a recognised carcinogen and a priority air pollutant owing to its respirable and toxic chemical components. There is a dearth of information in South Africa on cancer and non-cancer risks of exposure to heavy metal (HM) content of PM2.5. This study determined the seasonal concentration of HM in PM2.5 and the cancer and non-cancer risks of exposure to HM in PM2.5. Ambient PM2.5 was monitored and samples were collected during the winter and summer months in an industrialized area in South Africa. Concentration levels of nine HMs—As, Cu, Cd, Cr, Fe, Mn, Ni, Pb, and Zn—were determined in the PM2.5 samples using inductive coupled optical emission spectrophotometry. The non-cancer and cancer risks of each metal through the inhalation, ingestion and dermal routes were estimated using the Hazard Quotient and Excess Lifetime Cancer Risk (ELCR), respectively, among infants, children, and adults. Mean concentration of each HM-bound PM2.5 was higher in winter than in summer. The probability of the HM to induce non-cancer effects was higher during winter than in summer. The mean ELCR for HMs in PM2.5 (5.24 × 10−2) was higher than the acceptable limit of 10−6 to 10−4. The carcinogenic risk from As, Cd, Cr, Ni, and Pb were higher than the acceptable limit for all age groups. The risk levels for the carcinogenic HMs followed the order: Cr > As > Cd > Ni > Pb. The findings indicated that the concentrations of HM in PM2.5 demonstrated a season-dependent pattern and could trigger cancer and non-cancer health risks. The formulation of a regulatory standard for HM in South Africa and its enforcement will help in reducing human exposure to HM-bound PM2.5.

Developing a wavelet-AI hybrid model for short- and long-term predictions of the pollutant concentration of particulate matter10

Prediction of the particle concentration has received a great deal of research interest in recent decades, especially in the cities exposed to dust storms; hence, the use of early warning systems based on more accurate predictions to inform about the air quality situation in the next hours is very important. Thus, this study was conducted to improve the prediction accuracy of the particulate matter of aerodynamic diameter ≤ 2.5-μm particle concentration in the short term and long term, by combining the discrete wavelet transform technique with the artificial intelligence methods, i.e., adaptive neuro-fuzzy inference system, support vector regression, and artificial neural network. The data of the concentration of the suspended particles in Yazd city regarding 16 influential parameters were used during 2015–2019 in 6 models with and without wavelet, and the results obtained from these models were assessed and compared for hourly (short-term) and daily (long-term) timescales. The results based on 6 evaluation and validation criteria showed that the wavelet-support vector regression and wavelet-adaptive neuro-fuzzy inference system models have higher accuracy than other models in daily forecasting with an accuracy of about 99% and wavelet-support vector regression has higher accuracy in hourly forecasting with an accuracy of about 96%. The models combined with the wavelet transform produce better results rather than the single models showing the high effect of wavelet transformation in increasing the accuracy of artificial intelligence models used for prediction of the particulate matter ≤ 10 μm concentration.

The short-term association of ambient fine particulate air pollution with hypertension clinic visits: A multi-community study in Guangzhou, China

BackgroundThe association of ambient fine particulate pollution with daily outpatient clinic visits (OCV) for hypertension in China remains to be investigated. ObjectivesThis study aimed to examine short-term impacts of exposure to fine particulate matter of aerodynamic diameter < 2.5μm (PM2.5) on daily OCV for hypertension, using a large-scale multi-center community database in Guangzhou, one of the most densely-populated cities in Southern China. MethodsWe collected a total of 28,548 individual records of OCV from 22 community healthcare facilities in Guangzhou from January 1st to May 7th 2020. Hourly data on air pollutants and daily information on meteorological factors were obtained. According to the World Health Organization air-quality guidelines, daily excessive concentration hours (DECH) was calculated. PM2.5 daily mean, hourly-peak concentration and DECH were used as the exposure variables. Based on a case-time-control design, the Cox regression model was applied to evaluate the short-term relative risks (RR) of daily OCV for hypertension. Sensitivity analyses were conducted, with nitrogen dioxide, sulfur dioxide, carbon monoxide, and ozone being adjusted. ResultsDaily mean and hourly-peak of PM2.5 were significantly associated with daily OCV for hypertension, while weaker associations were observed for DECH. The estimated RRs at lag day 0 were 1.039 (95% confidence interval [CI]: 1.037, 1.040), 1.851 (95%CI: 1.814, 1.888), and 1.287 (95%CI: 1.276, 1.298), respectively, in association with a 1-unit increase in DECH, daily mean, and hourly-peak concentration of PM2.5. For the lagged effect, lag4 models estimated the greatest RRs for PM2.5 DECH and hourly-peak, whereas a lag2 model produced the highest for PM2.5 daily mean. DiscussionThis study consolidates the evidence for a positive correlation between ambient PM2.5 exposure and risks of hypertensive OCV. It also provides profound insight regarding planning for health services needs and establishing early environmental responses to the worsening air pollution in the communities.

Concentration levels, Carcinogenic and Mutagenic risks of PM2.5-bound Polycyclic Aromatic Hydrocarbons in an urban-industrial area in South Africa

Background: Concerns over the health effects of exposure to particulate matter of aerodynamic diameter of less than 2.5 μm (PM2.5) led the South African Government to establish the national standard for PM2.5 in the year 2012. However, there is currently no exposure limit for polycyclic aromatic hydrocarbons (PAHs) and PM2.5-bound PAHs. The understanding of the concentration levels and potential health risks of exposure to PM2.5-bound PAHs is important in ensuring a suitable risk assessment and risk management plan. This study, therefore, determined the concentration levels, carcinogenic and mutagenic health risks of PM2.5-bound PAHs. Methods: A hundred and forty-four PM2.5 samples were collected over four months during the winter and summer seasons of 2016 in an industrial area. The concentrations of 16 PAHs were analysed by gas chromatography-mass spectrometry, and their carcinogenic and mutagenic risks determined using the Human Health Risk Assessment model. Results: The mean winter (38.20±8.4 μg/m3) and summer (22.3±4.1 μg/m3) concentrations of PM2.5 levels were lower than the stipulated 40 μg/m3 daily limit. The main PAHs in PM2.5 were the lower molecular weight compounds accounting for 59.0% of the total concentration. The daily inhalation and ingestion exposure to PAHs for all age groups were higher than the daily exposure through the dermal contact. Children and adults are more likely to inhale and ingest PAHs in PM2.5 than infants. The excess cancer risks and excess mutagenic risk values were below the priority risk level (10-4). There is a potential risk of 1 to 8 per million persons developing cancer from exposure to Benzo[a]anthracene, Benzo[a]pyrene, Indeno[1,2,3-cd]pyrene, and Dibenz[a,h]anthracene over a lifetime of 70 years.Conclusions: The measured PAHs presented a seasonal variation, with higher concentrations observed in winter. These findings can equip relevant stakeholders and policymakers with the knowledge to institute strategies and plans for further emissions control.

Evaporation rates and pollutants emission from heated cooking oils and influencing factors

The heating of edible oils during cooking activities promotes the emissions of pollutants that have adverse impacts on the health of humans. This study investigated the evaporative emissions of fifteen (15) commonly used cooking oils. Split-plot experimental design under the response surface methodology framework was used to study singular and interaction effects of influencing parameters (temperature, volume of cooking oil and time) on cooking oil evaporation rate and pollutants emissions (i.e. Particulate matter of aerodynamic diameter ≤1 μm (PM1.0); ≤2.5 μm (PM2.5); ≤10 μm (PM10); Total Suspended Particulate (TSP); Total Volatile Organic Compounds -TVOCs, and Carbon Monoxide- CO) on a groundnut oil sample that served as a case study. Obtained values of density, viscosity, kinematic viscosity, smoke, flash and fire points were; 873–917 kg/m3; 1.12–9.7 kg/ms; 2.4–3.4 m2/s; 96 -100 °C; 124–179 °C and 142–186 °C, respectively. The role of temperature as the most significant parameter influencing the rate of evaporative emissions was established. Evaporation rate and pollutants emission from unrefined samples were the highest. The restricted maximum likelihood (REML) analysis results suggested a strong relationship between the actual values and the predicted values as R-squared values obtained were greater than 0.8 for all the responses. These results suggest that minimal rates of evaporation and pollutants emission from heating cooking oils can be achieved with a high volume of the cooking oil at moderate temperature levels.

Particle concentrations, dispersion modelling and evaluation in southern Sweden

Health impact assessments of differential air pollution rely on epidemiologically established relationships between concentration levels where people are exposed and adverse health outcomes. To assess air pollution concentrations, land use regression is commonly used. However, an alternative tool is dispersion modelling, where a detailed inventory of pollution sources together with meteorological data drives calculations of compound dispersion. With this, both spatial and temporal variation can be assessed. In this study, we evaluated results of a Gaussian dispersion model applied to an emissions inventory for Scania, the southernmost county in Sweden. The dispersion considered was particulate matter of aerodynamic diameter < 10 µm (PM10), particulate matter of aerodynamic diameter < 2.5 µm (PM2.5) and black carbon (BC) during an 11-year period (2000–2011). Mean concentrations and 95th percentiles expressed in µg/m3 ranged from 10.1 to 12.6 and 16.6 to 20.7 for PM2.5 and from 14.0 to 18.8 and 22.6 to 27.0 for PM10, respectively. Seven monitoring stations were used for evaluation. Correlations (R2) ranged from 0.44 to 0.86 for PM2.5 (mean bias from − 9.0 to 0.1 µg/m3) and from 0.46 to 0.83 for PM10 (mean bias − 6.1 to 3.5 µg/m3). An evaluated database of PM and BC concentrations for Scania is now available for future exposure assessment projects. Calculations were based on a well-known dispersion model with detailed emission data as input. The evaluation showed correlation coefficients for PM in line with previous literature. The data on PM10, PM2.5 and BC concentrations will, therefore, be used in subsequent studies, epidemiological as well as health impact assessments.