April 22 | 2019

Estimated Long-term (1981-2016) Concentrations of Ambient Fine Particulate Matter across North America from Chemical Transport Modeling, Satellite Remote Sensing and Ground-based Measurements.

Meng J, Li C, Martin RV, van Donkelaar A, Hystad P, Brauer M.

Environ Sci Technol. 2019 Apr 17. doi: 10.1021/acs.est.8b06875 . [Epub ahead of print]



Accurate data concerning historical fine particulate matter (PM2.5) concentrations are needed to assess long-term changes in exposure and associated health risks. We estimated historical PM2.5 concentrations over North America from 1981-2016 for the first time by combining chemical transport modeling, satellite remote sensing and ground-based measurements. We constrained and evaluated our estimates with direct ground-based PM2.5 measurements when available and otherwise with historical estimates of PM2.5 from PM10 measurements or total suspended particles (TSP) measurements. The estimated PM2.5 concentrations were generally consistent with direct ground-based PM2.5 measurements over their duration from 1988 onward (R2 = 0.6-0.85) and to a lesser extent with PM2.5 inferred from PM10 measurements from 1985 to 1998 (R2 =0.5-0.6). The collocated comparison of the trends of population-weighted annual average PM2.5 from our estimates and ground-based measurements were highly consistent (RMSD = 0.66 μg m-3). The population-weighted annual average PM2.5 over North America decreased from 22 6.4 μg m-3 in 1981, to 12 3.2 μg m-3 in 1998, and to 7.9 2.1 μg m-3 in 2016, with an overall trend of -0.33 μg m-3 yr-1 (95% CI: -0.35 -0.30).

April 15 | 2019

Environmental Exposures and Depression: Biological Mechanisms and Epidemiological Evidence.

van den Bosch M, Meyer-Lindenberg A.

Annu Rev Public Health. 2019 Apr 1;40:239-259. DOI: 10.1146/annurev-publhealth-040218-044106


Mental health and well-being are consistently influenced-directly or indirectly-by multiple environmental exposures. In this review, we have attempted to address some of the most common exposures of the biophysical environment, with a goal of demonstrating how those factors interact with central structures and functions of the brain and thus influence the neurobiology of depression. We emphasize biochemical mechanisms, observational evidence, and areas for future research. Finally, we include aspects of contextual environments-city living, nature, natural disasters, and climate change-and call for improved integration of environmental issues in public health science, policies, and activities. This integration is necessary for reducing the global pandemic of depression.



New to data science or looking to pick up a few new skills? Don’t miss these free webinars, guided practical tutorials and online resources featuring CANUE data.

Developed in partnership with Population Data BC



MODULE 1: Introduction to Machine Learning
January 15 | 11am to noon pacific: Overview webinar
January 17 | 11am to 1pm pacific: Guided practical tutorial

MODULE 2: Regression and Regularization Algorithms
January 29 | 11am to noon pacific: Overview webinar
January 31 | 11am to 1pm pacific: Guided practical tutorial

MODULE 3: Advanced Supervised Learning
February 12 | 11am to noon pacific: Overview webinar
February 14 | 11am to 1pm pacific: Guided practical tutorial

MODULE 4: Advanced Unsupervised Learning
February 26 | 11am to noon pacific: Overview webinar
February 28 | 11am to 1pm pacific: Guided practical tutorial

Dr. Aman Verma  is a Data Engineer with a PhD in Epidemiology from McGill University, and an undergraduate degree in Computer Science. He has experience in developing machine learning systems with large databases, particularly for scientific data in healthcare. While he’s comfortable learning any programming language, he’s recently become particularly interested in R. Aman is currently involved in a number of projects, including measuring how following opioid prescription guidelines can decrease the risk of opioid overdose, modelling trajectories of chronic obstructive pulmonary disease, and assessing how to best prioritize ambulance calls using secondary healthcare data.




This self paced free online course will provide you with an introduction to Data Management and Cleaning for Analysis using R Software. Each of the four modules includes a Power Point slide deck, CANUE training data, R code and associated exercises for practice.

Topics covered include:

  • Introduction and theory of data cleaning and management
  • Getting started with R software
  • Subsetting variables and data cleaning
  • Creating variables, subset observations and data cleaning
  • Merging, joining and reshaping data


Megan Striha currently works as a Data Analyst. She has a Masters of Public Health degree and three years of experience in health data analysis, including working with survey, administrative and census data.


Find out about new data and analytical methods, emerging research results, and applications to policy and practice…

April 8 | 2019

Risk of acute respiratory infection from crop burning in India: estimating disease burden and economic welfare from satellite and national health survey data for 250 000 persons.

Suman Chakrabarti, Mohammed Tajuddin Khan, Avinash Kishore, Devesh Roy, Samuel P Scott.

International Journal of Epidemiology, dyz022, https://doi.org/10.1093/ije/dyz022

Published: 28 February 2019



Respiratory infections are among the leading causes of death and disability globally. Respirable aerosol particles released by agricultural crop-residue burning (ACRB), practised by farmers in all global regions, are potentially harmful to human health. Our objective was to estimate the health and economic costs of ACRB in northern India.


The primary outcome was acute respiratory infection (ARI) from India’s fourth District Level Health Survey (DLHS-4). DLHS-4 data were merged with Moderate-Resolution Imaging Spectroradiometer satellite data on fire occurrence. Mutually adjusted generalized linear models were used to generate risk ratios for risk factors of ARI. Overall disease burden due to ACRB was estimated in terms of disability-adjusted life years.


Seeking medical treatment for ARI in the previous 2 weeks was reported by 5050 (2%) of 252 539 persons. Living in a district with intense ACRB—the top quintile of fires per day—was associated with a 3-fold higher risk of ARI (mutually adjusted risk ratio 2.99, 95% confidence interval 2.77 to 3.23) after adjustment for socio-demographic and household factors. Children under 5 years of age were particularly susceptible (3.65, 3.06 to 4.34 in this subgroup). Additional ARI risk factors included motor-vehicle congestion (1.96, 1.72 to 2.23), open drainage (1.91, 1.73 to 2.11), cooking with biomass (1.73, 1.58 to 1.90) and living in urban areas (1.35, 1.26 to 1.44). Eliminating ACRB would avert 14.9 million disability-adjusted life years lost per year, valued at US$152.9 billion over 5 years.


Investments to stop crop burning and offer farmers alternative crop-residue disposal solutions are likely to improve population-level respiratory health and yield major economic returns.

Spotlight: Dan Fuller

Dr. Daniel Fuller is a Canada Research Chair in Population Physical Activity and assistant professor in the School of Human Kinetics and Recreation at Memorial University. His research with CANUE is developing new Canadian indicators of urban sprawl, public transit accessibility, and active living environments.  

“My ultimate goal is a physically active Canadian population” says Dr. Fuller.

With that ambitious goal, is a motivated team of student researchers to match. Hui (Henry) Luan, Kassia Orychock, Javad Rahimipour Anaraki, and Melissa Tobin work alongside Dr. Fuller, to contribute to CANUE’s vision of increasing scientific understanding of the interactions among the physical features of the urban environment and health.  

“Our research is developing new, standardized, Canada-wide measures for urban environments. We are working with many Canadian researchers who are contributing their expertise to this large national initiative.”

Along with Dr. Michael Widener at the University of Toronto, we are also developing measures of food accessibility, and beginning discussions to develop measures of gentrification.

Connect with Dr. Fuller on TwitterFacebook, or check out Walkabilly.ca and beaplab.com.

April 1 | 2019

Temperature-related changes in airborne allergenic pollen abundance and seasonality across the northern hemisphere: a retrospective data analysis.

Ziska LH, Makra L, Harry SK, Bruffaerts N, Hendrickx M, Coates F, Saarto A, Thibaudon M, Oliver G, Damialis A, Charalampopoulos A, Vokou D, Heiđmarsson S, Guđjohnsen E, Bonini M, Oh JW, Sullivan K, Ford L, Brooks GD, Myszkowska D, Severova E, Gehrig R, Ramón GD, Beggs PJ, Knowlton K, Crimmins AR.

Lancet Planet Health. 2019 Mar;3 (3):e124-e131. https://doi.org/10.1016/S2542-5196(19)30015-4




Ongoing climate change might, through rising temperatures, alter allergenic pollen biology across the northern hemisphere. We aimed to analyse trends in pollen seasonality and pollen load and to establish whether there are specific climate-related links to any observed changes.


For this retrospective data analysis, we did an extensive search for global datasets with 20 years or more of airborne pollen data that consistently recorded pollen season indices (eg, duration and intensity). 17 locations across three continents with long-term (approximately 26 years on average) quantitative records of seasonal concentrations of multiple pollen (aeroallergen) taxa met the selection criteria. These datasets were analysed in the context of recent annual changes in maximum temperature (Tmax) and minimum temperature (Tmin) associated with anthropogenic climate change. Seasonal regressions (slopes) of variation in pollen load and pollen season duration over time were compared to Tmax, cumulative degree day Tmax, Tmin, cumulative degree day Tmin, and frost-free days among all 17 locations to ascertain significant correlations.


12 (71%) of the 17 locations showed significant increases in seasonal cumulative pollen or annual pollen load. Similarly, 11 (65%) of the 17 locations showed a significant increase in pollen season duration over time, increasing, on average, 0·9 days per year. Across the northern hemisphere locations analysed, annual cumulative increases in Tmax over time were significantly associated with percentage increases in seasonal pollen load (r=0·52, p=0·034) as were annual cumulative increases in Tmin (r=0·61, p=0·010). Similar results were observed for pollen season duration, but only for cumulative degree days (higher than the freezing point [0°C or 32°F]) for Tmax (r=0·53, p=0·030) and Tmin (r=0·48, p=0·05). Additionally, temporal increases in frost-free days per year were significantly correlated with increases in both pollen load (r=0·62, p=0·008) and pollen season duration (r=0·68, p=0·003) when averaged for all 17 locations.


Our findings reveal that the ongoing increase in temperature extremes (Tmin and Tmax) might already be contributing to extended seasonal duration and increased pollen load for multiple aeroallergenic pollen taxa in diverse locations across the northern hemisphere. This study, done across multiple continents, highlights an important link between ongoing global warming and public health-one that could be exacerbated as temperatures continue to increase.

Developing Apps for Population Health Research | APRIL 17 | 2019

9am – 10am pacific | 12 noon – 1pm eastern | 1:30pm – 2:30pm NFLD



Advances in technology, including mobile apps, have provided researchers with new ways to collect data. Health researchers are increasingly interested in developing and using mobile apps for research data collection. However, many challenges exist for health researchers when developing mobile apps. The purpose of this webinar is provide an overview of results of a report interviewing 8 researchers who have developed mobile apps. We will also provide recommendations for researchers who are planning to develop a health research apps.


Melissa Tobin is a Master of Science in Kinesiology student at Memorial University and an INTERACT Trainee. She is a graduate of the Bachelor of Kinesiology Honours (Co-op) Degree from Memorial University. Melissa’s master’s research will focus on how exposure to active transportation infrastructure influences physical activity levels. Melissa is very passionate about increasing physical activity levels for all members of our community.


Daniel Fuller is Canada Research Chair in Population Physical Activity in the School of Human Kinetics and Recreation at Memorial University. His research is focused on using wearable technologies to study physical activity, transportation interventions, and equity in urban spaces. He focuses his methodological work on methods for natural experiments, and machine learning.



March 18 | 2019

Vegetation diversity protects against childhood asthma: results from a large New Zealand birth cohort.

Donovan GH, Gatziolis D, Longley I, Douwes J.

Nat Plants. 2018 Jun;4(6):358-364. DOI: 10.1038/s41477-018-0151-8


We assessed the association between the natural environment and asthma in 49,956 New Zealand children born in 1998 and followed up until 2016 using routinely collected data. Children who lived in greener areas, as measured by the normalized difference vegetation index, were less likely to be asthmatic: a 1 s.d. increase in normalized difference vegetation index was associated with a 6.0% (95% CI 1.9–9.9%) lower risk of asthma. Vegetation diversity was also protective: a 1 s.d. increase in the number of natural land-cover types in a child’s residential meshblock was associated with a 6.7% (95% CI 1.5–11.5%) lower risk. However, not all land-cover types were protective. A 1 s.d. increase in the area covered by gorse (Ulex europaeus) or exotic conifers, both non-native, low-biodiversity land-cover types, was associated with a 3.2% (95% CI 0.0–6.0%) and 4.2% (95% CI 0.9–7.5%) increased risk of asthma, respectively. The results suggest that exposure to greenness and vegetation diversity may be protective of asthma.

March 11 | 2019

Geospatial analyses of adverse birth outcomes in Southwestern Ontario: Examining the impact of environmental factors.

Jamie A. Seabrook, Alexandra Smith, Andrew F. Clark, Jason A. Gilliland

Environmental Research Volume 172, May 2019, Pages 18-26 https://doi.org/10.1016/j.envres.2018.12.068




A growing body of research has examined the association between exposure to environmental factors during pregnancy and adverse birth outcomes; however, many studies do not control for potential covariates and findings vary considerably.


To test the relative influence of environmental factors including exposure to air pollution, major roads, highways, industry, parks, greenspaces, and food retailers on low birth weight (LBW) and preterm birth (PTB) in Southwestern Ontario (SWO), Canada, while accounting for medical (e.g., previous preterm birth, gestational diabetes), behavioral (e.g., alcohol, smoking), demographic (e.g., maternal age, body mass index), and neighborhood-level socioeconomic (e.g., household income, education) factors.


This retrospective cohort study consisted of a large sample of pregnant women from SWO who gave birth to singleton newborns between February 2009 and February 2014 at London Health Sciences Centre. Data on maternal postal codes were entered into a Geographic Information System to map the distribution of maternal residences and determine selected characteristics of their neighborhood environments (i.e., socioeconomic, built, natural). These variables were developed based on postal codes where the mothers lived prior to giving birth. Logistic regression was used to assess the relative effects of the physical environment, socioeconomic status, clinical history, and behavioral risk factors on mothers having a LBW or PTB infant.


Out of 25,263 live births, 5.7% were LBW and 7.5% were PTB. Exposure to sulfur dioxide was a top predictor of both LBW and PTB. For every one-unit increase in sulfur dioxide, the odds of a LBW and PTB were 3.4 (95% CI: 2.2, 5.2) and 2.0 (95% CI: 1.4, 3.0) times higher, after controlling for other variables in the model, respectively (p < 0.001). Previous PTB was also highly associated with both birth outcomes.


Health care providers should be informed about the hazards of air pollution to developing fetuses so that recommendations can be made to their pregnant patients about limiting exposure when air quality is poor.