The effect of portable HEPA filter air cleaners on indoor PM2.5 concentrations and second hand tobacco smoke exposure among pregnant women in Ulaanbaatar, Mongolia: The UGAAR randomized controlled trial

Background Portable HEPA filter air cleaners can reduce indoor fine particulate matter (PM2.5), but their use has not been adequately evaluated in high pollution settings. We assessed air cleaner effectiveness in reducing indoor residential PM2.5 and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia. Methods We randomized 540 participants to an intervention group receiving 1 or 2 HEPA filter air cleaners or a control group receiving no air cleaners. We followed 259 intervention and 253 control participants to the end of pregnancy. We measured one-week indoor residential PM2.5 concentrations in early (~11weeks gestation) and late (~31weeks gestation) pregnancy and collected outdoor PM2.5 data from centrally-located government monitors. We assessed blood cadmium in late pregnancy. Hair nicotine was quantified in a subset (n=125) to evaluate blood cadmium as a biomarker of SHS exposure. We evaluated air cleaner effectiveness using mixed effects and multiple linear regression models and used stratified models and interaction terms to evaluate potential modifiers of effectiveness. Results The overall geometric mean (GM) one-week outdoor PM2.5 concentration was 47.9?g/m3 (95% CI: 44.6, 51.6?g/m3), with highest concentrations in winter (118.0?g/m3; 110.4, 126.2?g/m3). One-week indoor and outdoor PM2.5 concentrations were correlated (r=0.69). Indoor PM2.5 concentrations were 29% (21, 37%) lower in intervention versus control apartments, with GMs of 17.3?g/m3 (15.8, 18.8?g/m3) and 24.5?g/m3 (22.2, 27.0?g/m3), respectively. Air cleaner effectiveness was greater when air cleaners were first deployed (40%; 31, 48%) than after approximately five months of use (15%; 0, 27%). Blood cadmium concentrations were 14% (4, 23%) lower among intervention participants, likely due to reduced SHS exposure. Conclusions Portable HEPA filter air cleaners can lower indoor PM2.5 concentrations and SHS exposures in highly polluted settings.Canadian Institute of Health Research (MOP 142380)Simon Fraser University, Faculty of Health Sciences (Mowafaghian Child Health Faculty Award

Air pollution, green space and dementia risk in Canada

Dementia is a major global population health challenge. It is not curable, and severity worsens over time. With seniors expected to comprise approximately 25% of the Canadian population by 2035, cases of dementia and its related health and financial burden are forecast to dramatically increase in the next decades. While some well-known risk factors for dementia are identified (e.g. age, sex), they do not fully explain dementia risk, therefore other potentially modifiable risk factors may be unidentified. Mounting evidence suggests connections between environmental factors and dementia, however associations between exposure to air pollution and dementia have not been adequately studied, nor have the potential protective effects of residing in neighbourhoods with more natural green space. To address these gaps, we investigated the links between long-term exposure to air pollution (e.g. fine particulate matter, PM₂ꓸ₅; nitrogen dioxide, NO₂), dementia, and the possible beneficial impacts from green space (Normalized Difference Vegetation Index) within three large population-based cohorts. In the Metro Vancouver cohort, air pollutants were associated with incidence of non-Alzheimer’s dementia (e.g., hazard ratios (HR) of 1.02 [0.98-1.05], 1.02 [0.99-1.06] per interquartile range increase in PM₂ꓸ₅ and NO₂). In the national 2001 Canadian Census Health and Environment Cohort, PM₂ꓸ₅ (1.09 [95% CI:1.08-1.10] per interquartile range increase) and NO₂ (1.08 [95% CI:1.07-1.09]) were associated with dementia mortality. These findings were supported by analysis of the Canadian Community Health Survey where individual behavioural risk factors (smoking, alcohol consumption, etc.) were available. Air pollutants were associated with increased dementia mortality (e.g., dementia HR of 1.25 [1.23-1.27] and 1.23 [1.21-1.25] per interquartile range increase in PM₂ꓸ₅ and NO₂, while HRs were attenuated (1.14 [1.12-1.16] and 1.17 [1.15-1.19]) in models including behavioural risk factors. Across the three cohorts, greenness was associated with 1-5% risk reduction in dementia. These results indicate that air pollution, even at relatively low concentrations, was linked with dementia, while living in greener areas was found to have some small protective effects. These findings contribute to the overall understanding of the relationships between built-in environment factors and dementia and can contribute to the development of public health approaches for dementia risk reduction.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofGraduat

Modelling Fine Particulate Matter Concentrations inside the Homes of Pregnant Women in Ulaanbaatar, Mongolia

Fine particulate matter (PM2.5) is a leading public health risk factor globally. Indoor concentrations are an important determinant of exposure because people spend the majority of time indoors. I developed models for predicting PM2.5 concentrations inside the homes of pregnant women in Ulaanbaatar, Mongolia. The work was part of a randomized controlled trial of portable air cleaner use during pregnancy, fetal growth, and early childhood development. Multiple linear regression (MLR) and random forest regression (RFR) were used to model indoor PM2.5 concentrations using 7-day indoor PM2.5 measurements and potential predictors obtained from outdoor monitoring data, questionnaires, home assessments, and geographic data sets. The MLR (R2 = 50.5%) and RFR (R2 = 47.8%) models explained a moderate amount of variation in log-transformed indoor PM2.5. Model predictions can be used to evaluate associations between indoor PM2.5 concentrations during pregnancy and development in early life

Road proximity, air pollution, noise, green space and neurologic disease incidence: a population-based cohort study

Background: Emerging evidence links road proximity and air pollution with cognitive impairment. Joint effects of noise and greenness have not been evaluated. We investigated associations between road proximity and exposures to air pollution, and joint effects of noise and greenness, on non-Alzheimer’s dementia, Parkinson’s and Alzheimer’s disease and multiple sclerosis within a population-based cohort. Methods: We assembled administrative health database cohorts of 45–84 year old residents (N ~ 678,000) of Metro Vancouver, Canada. Cox proportional hazards models were built to assess associations between exposures and non-Alzheimer’s dementia and Parkinson’s disease. Given reduced case numbers, associations with Alzheimer’s disease and multiple sclerosis were evaluated in nested case-control analyses by conditional logistic regression. Results: Road proximity was associated with all outcomes (e.g. non-Alzheimer’s dementia hazard ratio: 1.14, [95% confidence interval: 1.07–1.20], for living < 50 m from a major road or < 150 m from a highway). Air pollutants were associated with incidence of Parkinson’s disease and non-Alzheimer’s dementia (e.g. Parkinson’s disease hazard ratios of 1.09 [1.02–1.16], 1.03 [0.97–1.08], 1.12 [1.05–1.20] per interquartile increase in fine particulate matter, Black Carbon, and nitrogen dioxide) but not Alzheimer’s disease or multiple sclerosis. Noise was not associated with any outcomes while associations with greenness suggested protective effects for Parkinson’s disease and non-Alzheimer’s dementia. Conclusions: Road proximity was associated with incidence of non-Alzheimer’s dementia, Parkinson’s disease, Alzheimer’s disease and multiple sclerosis. This association may be partially mediated by air pollution, whereas noise exposure did not affect associations. There was some evidence of protective effects of greenness.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofReviewedFacult

Integrating travel behavior with land use regression to estimate dynamic air pollution exposure in Hong Kong

Background: Epidemiological studies typically use subjects’ residential address to estimate individuals’ air pollution exposure. However, in reality this exposure is rarely static as people move from home to work/study locations and commute during the day. Integrating mobility and time-activity data may reduce errors and biases, thereby improving estimates of health risks. Objectives: To incorporate land use regression with movement and building infiltration data to estimate time-weighted air pollution exposures stratified by age, sex, and employment status for population subgroups in Hong Kong. Methods: A large population-representative survey (N = 89,385) was used to characterize travel behavior, and derive time-activity pattern for each subject. Infiltration factors calculated from indoor/outdoor monitoring campaigns were used to estimate micro-environmental concentrations. We evaluated dynamic and static (residential location-only) exposures in a staged modeling approach to quantify effects of each component. Results: Higher levels of exposures were found for working adults and students due to increased mobility. Compared to subjects aged 65 or older, exposures to PM2.5, BC, and NO2 were 13%, 39% and 14% higher, respectively for subjects aged below 18, and 3%, 18% and 11% higher, respectively for working adults. Exposures of females were approximately 4% lower than those of males. Dynamic exposures were around 20% lower than ambient exposures at residential addresses. Conclusions: The incorporation of infiltration and mobility increased heterogeneity in population exposure and allowed identification of highly exposed groups. The use of ambient concentrations may lead to exposure misclassification which introduces bias, resulting in lower effect estimates than ‘true’ exposures

Neighborhood environmental exposures and incidence of attention deficit/hyperactivity disorder: A population-based cohort study

Background: Emerging studies have associated low greenspace and high air pollution exposure with risk of child attention deficit/hyperactivity disorder (ADHD). Population-based studies are limited, however, and joint effects are rarely evaluated. We investigated associations of ADHD incidence with greenspace, air pollution, and noise in a population-based birth cohort. Methods: We assembled a cohort from administrative data of births from 2000 to 2001 (N ∼ 37,000) in Metro Vancouver, Canada. ADHD was identified by hospital records, physician visits, and prescriptions. Cox proportional hazards models were applied to assess associations between environmental exposures and ADHD incidence adjusting for available covariates. Greenspace was estimated using vegetation percentage derived from linear spectral unmixing of Landsat imagery. Fine particulate matter (PM2.5) and nitrogen dioxide (NO2) were estimated using land use regression models; noise was estimated using a deterministic model. Exposure period was from birth until the age of three. Joint effects of greenspace and PM2.5 were analysed in two-exposure models and by categorizing values into quintiles. Results: During seven-year follow-up, 1217 ADHD cases were diagnosed. Greenspace was associated with lower incidence of ADHD (hazard ratio, HR: 0.90 [0.81-0.99] per interquartile range increment), while PM2.5 was associated with increased incidence (HR: 1.11 [1.06-1.17] per interquartile range increment). NO2 (HR: 1.01 [0.96, 1.07]) and noise (HR: 1.00 [0.95, 1.05]) were not associated with ADHD. There was a 50% decrease in the HR for ADHD in locations with the lowest PM2.5 and highest greenspace exposure, compared to a 62% increase in HR in locations with the highest PM2.5 and lowest greenspace exposure. Effects of PM2.5 were attenuated by greenspace in two-exposure models. Conclusions: We found evidence suggesting environmental inequalities where children living in greener neighborhoods with low air pollution had substantially lower risk of ADHD compared to those with higher air pollution and lower greenspace exposure.This work was supported by the Canadian Institutes of Health Research (grant number:156152) and by the European Union's Horizon 2020 research and innovation programme under a Marie Skłodowska-Curie Grant Agreement No 891538. Data were made accessible via Population Data BC. National air pollution estimates, Canadian Marginalization index, and NDVI metrics indexed to DMTI Spatial Inc. postal codes were provided by CANUE (Canadian Urban Environmental Health Research Consortium). We are grateful for the support of the Integrated Remote Sensing Studio (IRSS) at the University of British Columbia, and Nicholas Coops for development of the Landsat greenness time series. The data that support the findings of this study are available from the Medical Services Plan of British Columbia and other Data Stewards but restrictions apply to the availability of these data, which were used under agreement for the current study, and so are not openly available. Data are however accessible via Population Data BC and the relevant Data Stewards following approval of a Data Access Request and within the terms of Population Data BC access. All inferences, opinions, and conclusions drawn in this manuscript are those of the authors, and do not reflect the opinions or policies of the Data Steward(s)

The effect of portable HEPA filter air cleaners on indoor PM2.5 concentrations and second hand tobacco smoke exposure among pregnant women in Ulaanbaatar, Mongolia: The UGAAR randomized controlled trial

Background Portable HEPA filter air cleaners can reduce indoor fine particulate matter (PM2.5), but their use has not been adequately evaluated in high pollution settings. We assessed air cleaner effectiveness in reducing indoor residential PM2.5 and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia. Methods We randomized 540 participants to an intervention group receiving 1 or 2 HEPA filter air cleaners or a control group receiving no air cleaners. We followed 259 intervention and 253 control participants to the end of pregnancy. We measured one-week indoor residential PM2.5 concentrations in early (~11weeks gestation) and late (~31weeks gestation) pregnancy and collected outdoor PM2.5 data from centrally-located government monitors. We assessed blood cadmium in late pregnancy. Hair nicotine was quantified in a subset (n=125) to evaluate blood cadmium as a biomarker of SHS exposure. We evaluated air cleaner effectiveness using mixed effects and multiple linear regression models and used stratified models and interaction terms to evaluate potential modifiers of effectiveness. Results The overall geometric mean (GM) one-week outdoor PM2.5 concentration was 47.9?g/m3 (95% CI: 44.6, 51.6?g/m3), with highest concentrations in winter (118.0?g/m3; 110.4, 126.2?g/m3). One-week indoor and outdoor PM2.5 concentrations were correlated (r=0.69). Indoor PM2.5 concentrations were 29% (21, 37%) lower in intervention versus control apartments, with GMs of 17.3?g/m3 (15.8, 18.8?g/m3) and 24.5?g/m3 (22.2, 27.0?g/m3), respectively. Air cleaner effectiveness was greater when air cleaners were first deployed (40%; 31, 48%) than after approximately five months of use (15%; 0, 27%). Blood cadmium concentrations were 14% (4, 23%) lower among intervention participants, likely due to reduced SHS exposure. Conclusions Portable HEPA filter air cleaners can lower indoor PM2.5 concentrations and SHS exposures in highly polluted settings.Canadian Institute of Health Research (MOP 142380)Simon Fraser University, Faculty of Health Sciences (Mowafaghian Child Health Faculty Award