Presented at 'Changing Perspectives: 1st International Conference on Transport and Health', London, 6 -8 July 2015
Haneen Khreis, Charlotte Kelly, James Tate, Roger Parslow, Karen Lucas
Presented at 'Changing Perspectives: 1st International Conference on Transport and Health', London, 6 -8 July 2015
Haneen Khreis, Charlotte Kelly, James Tate, Roger Parslow, Karen Lucas
2023 Undergraduate Research Symposium: Taral Patel and Sophie Habashy
Asthma negatively affects the quality of life of those who suffer from it, with the acknowledgment that the African American/Black community is disproportionately afflicted by the disease. Research suggests that increased atmospheric particulate matter among other pollutants is correlated with higher rates of reported asthma symptoms and hospitalizations.
The present study describes the methodology of cross-referencing Environmental Protection Agency (EPA) reported daily particulate matter 2.5 (PM2.5) with participant laboratory visits with the goal of allowing researchers to assess the effect of this pollutant with concurrent reports of psychosocial and asthma measures. Part of this data comes from the Asthma in the Lives of Families Today study which investigated psychosocial predictors of asthma-related health among African American children from the Detroit area between 2011-2018. Determining PM2.5 levels on lab visit days was conducted in multiple steps. Firstly, participants' zip codes were used to determine their geographical census block (i.e., GEOID). Next, GEOIDs were matched to the most closely located EPA PM2.5 sites of the twelve stationed in Wayne County.
After the EPA site was matched to the participant, the PM2.5 measurement on the day of each participant's ALOFT visit was identified. This methodological approach provided a clear air pollution reference on the date of lab visits, allowing ALOFT researchers to investigate its specific and subsequent impact on child asthma health.
Exposure to outdoor air pollution and its effect.pptxdipakghimire77
Outdoor air pollution is a complex and pervasive environmental issue that affects millions of people worldwide. The continuous release of pollutants into the atmosphere from various sources has led to widespread exposure, contributing to a range of health problems. This comprehensive review explores the sources, composition, and health effects of outdoor air pollution, emphasizing the significance of addressing this global challenge.
Observational study is divided into descriptive and analytical studies.
Non-experimental
Observational because there is no individual intervention
Treatment and exposures occur in a “non-controlled” environment
Individuals can be observed prospectively or retrospectively
COHORT STUDY- an “observational” design comparing individuals with a known risk factor or exposure with others without the risk factor or exposure.
looking for a difference in the risk (incidence) of a disease over time.
best observational design
data usually collected prospectively (some retrospective)
CASE CONTROL - EFFECT TO CAUSE
Retrospective
When disease is rare
.
Cómo distinguir una investigación seria de una fraudulentaantenasysalud
Segunda presentación del Dr. Mike Repacholi, presidente emérito del ICNIPR (Comisión Internacional de Protección contra la Radiación No Ionizante) y Miembro del Comité Asesor Internacional del Proyecto de EMF Internacional de la Organización Mundial de la Salud, durante el II Foro Internacional “Antenas y Telecomunicaciones; Inclusiòn, Desarrollo y Salud Humana. Repacholi ofreció una disertación focalizada a resaltar las diferencias entre investigaciones científicas serias y fraudulentas que muchas veces ganan gran atención de la prensa generando temor entre la población respecto a las presuntas relaciones entre la radiación que emiten las antenas y sus efectos en la salud.
Exposure assessment for occupational epidemiology part 2Retired
The aim of this lecture is to provide an introduction to occupational exposures and the strategies used in epidemiological studies to assess exposure of subjects.
www.nhtnetwork.org/cqc-efficiency-network/home
The CQC Efficiency Network is a collaborative venture between ITS researcher Dr Phill Wheat and leading
performance and benchmarking company measure2improve (m2wi). Dr Wheat has used funding from the EPSRC
Impact Acceleration Account (IAA) to refine the tools to support m2i in developing the fast growing network. The IAA is an institutional award funded by EPSRC to help speed up the contribution that engineering and physical science research make towards new innovation, successful businesses and
the economic returns that benefit UK plc.
Posters summarizing dissertation research projects - presented by MSc students at the Institute for Transport Studies (ITS), University of Leeds, April 2017. http://bit.ly/2re35Cs
www.its.leeds.ac.uk/courses/masters/dissertation
Cutting-edge transport research showcased to Secretary of State during the event to officially re- open the Institute building www.leeds.ac.uk/news/article/4011/cutting-edge_transport_research_showcased_to_secretary_of_state
DR STEPHEN HALL, PROFESSOR SIMON SHEPHERD, DR ZIA WADUD; UNIVERSITY OF LEEDS, IN COLLABORATION WITH FUTURE CITIES CATAPULT
Also see https://theconversation.com/five-reasons-why-you-might-be-driving-electric-sooner-than-you-think-71896
Presentation Fiona Crawford - winner of the Smeed prize for best student paper at the UTSG Conference 2017
www.its.leeds.ac.uk/people/f.crawford
www.utsg.net/web/index.php?page=annual-conference
Efforts to reduce the emissions from car travel have so far been hampered by a lack of specific information on car ownership and use. The Motoring and vehicle Ownership Trends in the UK (MOT) project seeks to address this by bringing together new sources of data to give a spatially and disaggregated diagnosis of car ownership and use in Great Britain and the associated energy demand and emissions.
Data from annual car M.O.T tests, made available by the Department for Transport, will be used as a platform upon which to develop and undertake a set of inter-linked modelling and analysis tasks using multiple sources of vehicle-specific and area-based data. Through this the project will develop the capability to understand spatial and temporal differences in car ownership and use, the determinants of those differences, and how levels may change over time and in response to various policy measures. The relationship between fuel use and emissions, and the demographic, economic, infrastructural and socio-cultural factors influencing these will also be tested.
Consequently, the MOT project has the potential to transform the way in which energy and emissions related to car use are quantified, understood and monitored to help refine future research and policy agendas and to inform transport and energy infrastructure planning.
www.its.leeds.ac.uk/research/featured-projects/mot
The University's Annual Review covering the 2015-16 academic year. This new publication gives an overview of some of the most important initiatives and activities that the University has undertaken recently and a sense of the scale of the ambition for the future.
www.its.leeds.ac.uk/people/c.calastri
Social networks, i.e. the circles of people we are socially connected to, have been recognised to play a role in shaping our travel and activity behaviour. This not only has to do with socialisation being the purpose of travel, but also with enabling mobility and other activities through the so-called social capital. Another theme in the literature connecting social environment and travel behaviour is social influence, i.e. the investigation of how travel behaviour can be affected by observation or comparison with other people. Research about the impact of social influence on travel choices is still at its infancy. In this talk, I will give an overview of how choice modelling can be used to investigate the relationships between social networks, travel and activities. I will touch upon work that I have done so far, in particular I will describe my applications of the Multiple Discrete-Continuous Extreme Value (MDCEV) model to frequency of social interactions as well as to allocation of time to different activities, taking the social dimension into account. In these studies, I make use of social network and travel data collected in places as diverse as Switzerland and Chile. I will also discuss ongoing work making use of longitudinal life-course data to model the impact of family of origin and the “mobility environment” people grew up in on travel decision of adults. Finally, I will outline future plans about modelling behavioural changes due to social influence using the smartphone app travel data that are being collected in Leeds within the “Choices and consumption: modelling long and short term decisions in a changing world” (“DECISIONS”) project.
Shigeki Oxawa is Associate Professor at the Department of Integrated Informatics, Daido University and part-time Lecturer in Transport Economics at Hosei University. He is a transport economist with a strong interest in transport policy. He is currently an academic visitor at Leeds University (April 2016-March 2017) working in the area of intermodal transport (with a focus on rail freight transport) and in turn track access charges.
Abstract: In the national railway revolution in Japan, the passenger division was divided into 6 companies by regions. They operate trains and own/manage the rail track (vertical integration system). On the other hand, vertical separation was introduced into freight companies, therefore, freight companies have to access rail track owned/managed by passenger companies. The Japanese regulator regards track access transactions between passenger companies and freight companies as private business.
In the vertical separation system, freight companies cannot get access to the slots required and efficient allocation of rail track cannot be achieved. The vertical separation is a very significant issue in railway policy and freight transport policy in Japan. In the presentation, causes and possible solutions to the issue will be shown.
Shigeki is Associate Professor at the Department of Integrated Informatics, Daido University and part-time Lecturer in Transport Economics at Hosei University. He is a transport economist with a strong interest in transport policy. He is currently an academic visitor at Leeds University (April 2016-March 2017) working in the area of intermodal transport (with a focus on rail freight transport) and in turn track access charges. He has 20 years of experience in research and teaching.
Presentation from NORTHMOST - a new biannual series of meetings on the topic of mathematical modelling in transport.
Hosted at its.leeds.ac.uk, NORTHMOST 01 focussed on academic research, to encourage networking and collaboration between academics interested in the methodological development of mathematical modelling applied to transport.
The focus of the meetings will alternate; NORTHMOST 02 - planned for Spring 2017 - will be led by practitioners who are modelling experts. Practitioners will give presentations, with academic researchers in the audience. In addition to giving a forum for expert practitioners to meet and share best practice, a key aim of the series is to close the gap between research and practice, establishing a feedback loop to communicate the needs of practitioners to those working in university research.
Presentation from NORTHMOST - a new biannual series of meetings on the topic of mathematical modelling in transport.
Hosted at its.leeds.ac.uk, NORTHMOST 01 focussed on academic research, to encourage networking and collaboration between academics interested in the methodological development of mathematical modelling applied to transport.
The focus of the meetings will alternate; NORTHMOST 02 - planned for Spring 2017 - will be led by practitioners who are modelling experts. Practitioners will give presentations, with academic researchers in the audience. In addition to giving a forum for expert practitioners to meet and share best practice, a key aim of the series is to close the gap between research and practice, establishing a feedback loop to communicate the needs of practitioners to those working in university research.
Presentation from NORTHMOST - a new biannual series of meetings on the topic of mathematical modelling in transport.
Hosted at its.leeds.ac.uk, NORTHMOST 01 focussed on academic research, to encourage networking and collaboration between academics interested in the methodological development of mathematical modelling applied to transport.
The focus of the meetings will alternate; NORTHMOST 02 - planned for Spring 2017 - will be led by practitioners who are modelling experts. Practitioners will give presentations, with academic researchers in the audience. In addition to giving a forum for expert practitioners to meet and share best practice, a key aim of the series is to close the gap between research and practice, establishing a feedback loop to communicate the needs of practitioners to those working in university research.
Presentation from NORTHMOST - a new biannual series of meetings on the topic of mathematical modelling in transport.
Hosted at its.leeds.ac.uk, NORTHMOST 01 focussed on academic research, to encourage networking and collaboration between academics interested in the methodological development of mathematical modelling applied to transport.
The focus of the meetings will alternate; NORTHMOST 02 - planned for Spring 2017 - will be led by practitioners who are modelling experts. Practitioners will give presentations, with academic researchers in the audience. In addition to giving a forum for expert practitioners to meet and share best practice, a key aim of the series is to close the gap between research and practice, establishing a feedback loop to communicate the needs of practitioners to those working in university research.
Presentation from NORTHMOST - a new biannual series of meetings on the topic of mathematical modelling in transport.
Hosted at its.leeds.ac.uk, NORTHMOST 01 focussed on academic research, to encourage networking and collaboration between academics interested in the methodological development of mathematical modelling applied to transport.
The focus of the meetings will alternate; NORTHMOST 02 - planned for Spring 2017 - will be led by practitioners who are modelling experts. Practitioners will give presentations, with academic researchers in the audience. In addition to giving a forum for expert practitioners to meet and share best practice, a key aim of the series is to close the gap between research and practice, establishing a feedback loop to communicate the needs of practitioners to those working in university research.
Presentation from NORTHMOST - a new biannual series of meetings on the topic of mathematical modelling in transport.
Hosted at its.leeds.ac.uk, NORTHMOST 01 focussed on academic research, to encourage networking and collaboration between academics interested in the methodological development of mathematical modelling applied to transport.
The focus of the meetings will alternate; NORTHMOST 02 - planned for Spring 2017 - will be led by practitioners who are modelling experts. Practitioners will give presentations, with academic researchers in the audience. In addition to giving a forum for expert practitioners to meet and share best practice, a key aim of the series is to close the gap between research and practice, establishing a feedback loop to communicate the needs of practitioners to those working in university research.
More from Institute for Transport Studies (ITS) (20)
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Basavarajeeyam is a Sreshta Sangraha grantha (Compiled book ), written by Neelkanta kotturu Basavaraja Virachita. It contains 25 Prakaranas, First 24 Chapters related to Rogas& 25th to Rasadravyas.
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Adv. biopharm. APPLICATION OF PHARMACOKINETICS : TARGETED DRUG DELIVERY SYSTEMSAkankshaAshtankar
MIP 201T & MPH 202T
ADVANCED BIOPHARMACEUTICS & PHARMACOKINETICS : UNIT 5
APPLICATION OF PHARMACOKINETICS : TARGETED DRUG DELIVERY SYSTEMS By - AKANKSHA ASHTANKAR
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
The Gram stain is a fundamental technique in microbiology used to classify bacteria based on their cell wall structure. It provides a quick and simple method to distinguish between Gram-positive and Gram-negative bacteria, which have different susceptibilities to antibiotics
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Exposure to traffic related air pollution and the onset of childhood asthma is there a connection
1. Institute for Transport Studies
FACULTY OF ENVIRONMENT
Exposure to traffic-related air pollution
and the onset of childhood asthma: is
there a connection?
Haneen Khreis1, Charlotte Kelly1,2, James Tate1, Roger Parslow3 and Karen Lucas1
1Institute for Transport Studies, 2Academic Unit for Health Economics, 3Division of
Epidemiology and Biostatistics
5. Childhood asthma on the rise
• A complex inflammatory
disorder of the airways
• Significant and steady
increases in prevalence after
the 1950’s
• “… the increase in disease
must be attributable to a
change in as-yet unknown
environmental factors”
(Cookson, 2004)
Patients consulting general practitioners for asthma per 10 000
population, England and Wales, 1955–1998. Data from the General
Practice Research Database (GPRD) and Morbidity Statistics in
General Practice (MSGP). y, year, (Anderson et al. 2007)
6. Conventional wisdom about air
pollution and asthma
• Air pollution can exacerbate existing asthma
• Unclear and debatable whether air pollution can cause asthma
• Was argued that air pollution can be excluded as a plausible
cause of asthma as air quality improved when asthma
prevalence was on the rise (Anderson 1997, Koenig 1999)
1 2
7. Challenging the conventional
wisdom
“…I think we’ve been looking for the last thirty years at
the wrong pollutant mixture and I also think as you’ll see,
I think that that history has got in the way of advancing
our understanding of the role of air pollution in asthma,
and has limited our approach to risk assessment…”
Rob S. McConnell, MD. Professor of Preventive Medicine, USC, at Symposium on
Cumulative Impacts and Children's Environmental Health 2013
8. Overall methodology
Does children’s exposure to
traffic-related air pollution
increase their risks of
developing asthma?
Meta-analysis
Case study
Systematic review
Provide data
Learn and apply lessons
9. Eligibility criteria
Does children’s exposure to traffic-related air pollution
increase their risks of developing asthma?
3. Include studies which investigate children’s
exposure to traffic-related air pollution only1. Include human
studies only 2. and
children’s studies only
4. Include studies which investigate exposure to
traffic-related air pollution or traffic-related air
pollutants when road traffic is specified as their source
6. Include studies which
specifically investigate asthma’s
development risks in childhood
7. Include observational studies only
5. Include studies which
report measures of
association and their
confidence interval precision
10. Search strategy
• Protocol registered specifying methods/ stages (Khreis et al., 2014)
• Structured searches in EMBASE, MEDLINE, Transport Database
• No language or study date restriction in database searches in
line with CRD guidance (Tacconelli, 2010)
Population
Child*
Child*
Child*
Child*
Exposure
Air pollution
Air quality
Vehicle emissions
Ultrafine particles
Outcome
Asthma
Asthma
Asthma
Asthma
11. Studies identified
by the databases
searches N = 3,784
Studies identified
from previous
literature review N
= 16
Titles and abstracts screened N = 2,620
Excluded N = 1,180;
duplicates and triplets
Potentially relevant studies to be full-text screened for
eligibility N = 61
Random 10%
independently
screened by CK
Excluded N = 2,559;
one or more of
eligibility criteria
unmet
Full copies obtained and assessed for eligibility N = 55
Excluded N = 6;
1 review, 1 foreign
language, 3 abstracts
no paper, 1 abstract
paper included
Publications meeting inclusion criteria and included in
the review N = 21
Random 10%
independently
screened by JT
References lists screening: identified 3
reviews (+3 reviews from stage 1), data
extraction, and quality assessment
3 relevant reviews
from stage 1
13th August 2014 - 6th March 2015
Excluded N = 34; one
or more eligibility
criteria unmet
Stage 1
Stage 2
Stage 3
12. Data extraction and quality
assessment (CASP, 2004)
• Study design
• Cohort vs case-control
• Recruitment and selection bias
• Representative? Anything special? Everyone included?
• Sample size
• Statistical power to detect effects
• Age group
• Any critical exposure windows?
• Completion and length of the follow-up
• Do persons lost to follow-up have different outcomes? Is follow-up long enough to reveal effects?
• Adjustment for confounders and other risk factors
• Identification, control and adjustment for confounders and other asthma risk factor?
• Exposure assessment methods
• Methods? Limitations? Validation? Traffic-related pollutants studied?
14. Lack of emphasis on asthma onset
• Only 21 studies identified [1999-2014]
• But almost every other study looked at air pollution and asthma
exacerbations or asthma prevalence at one point in time
• Why is the evidence for the effect of exposure to traffic-related air
pollution on asthma’s onset considerably less developed?
• Lack of population cohorts capable of assessing disease onset?
• Access to/ utilization of cohort studies data limited by costs, ethics and
multidisciplinary collaboration?
• Whether a causal relationship between traffic-related air pollution and
asthma exist is not only a question for epidemiologists, but is also a
question of biological plausibility
19. General characteristics (16 cohorts)
• Sample sizes
• Ranged from 184 to 37,401 children
• Follow-up periods
• Ranged from 2 to 12 years (11 studies were birth cohorts)
• Exposure validation
• 8 studies reported some kind of exposure validation
• Exposure calculated at:
• At the home address: 15 studies
• At the school address: 1 study
• Adjustment for confounders
• Smoking, socio-economic status, indoor air pollution sources, gender, family
history of asthma and allergies, low birth weight and gestational period
21. Asthma’s definitions and almost no
categorization!
• 9 studies > questionnaires’ self or parental reporting of doctor-
diagnosed asthma
• Diagnostic criteria/ practices vary among countries/ physicians
• Asthma prevalence estimates significantly differ using parental
report of doctor diagnoses vs. medication data vs. hospitalization
registry (Hansen et al., 2012)
• 7 studies > symptoms reporting, asthma treatment, primary care
billing/ hospital discharge records
• Symptoms are non specific
• Asthma is heterogeneous in nature, has different endotypes with
distinct underlying mechanisms
• Only 2 studies categorized asthma as allergic vs. non-allergic
23. Traffic-related air pollution is highly
heterogeneous in space and in time
Fay D, Tate J, Khreis H, (2015): Investigating pedestrians
PNC exposures in urban micro-environments near a busy
road traffic intersection
24. Traffic-related air pollution is highly
heterogeneous in space and in time
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Background
Site
Background
Site
Intersection
Corner
Bus
Stop
Road
Crossing
Bus
Stop
Intersection
Corner
Road
Crossing
Intersection
Corner
Intersection
Corner
Road
Crossing
25. Land-use regression models: 7
studies
Land use area/ # of buildings =
BUILDINGS
Total traffic load of all roads in
buffer = TRAFLOAD
Sum of green, natural, forested
area in buffer = NATURAL
Heavy duty traffic intensity on
nearest major road=
HEAVYTRAFMAJOR
Traffic intensity on nearest major
road = TRAFMAJOR
NO2 = 16.52 + 7.81E-5*BUILDINGS_300 + 5.86E-
6*TRAFLOAD_25 + 3.20E-8*TRAFLOAD_25_1000 −
1.09E-4*NATURAL_300 + 7.43E-4*HEAVYTRAFMAJOR
(Beelen et al., 2013)
PICTURES HAVE BEEN REMOVED DUE TO
CONFIDENTIALITY ISSUES
26. Land-use regression models: 7
studies
NO2 = 16.52 + 7.81E-5*BUILDINGS_300 + 5.86E-
6*TRAFLOAD_25 + 3.20E-8*TRAFLOAD_25_1000 −
1.09E-4*NATURAL_300 + 7.43E-4*HEAVYTRAFMAJOR
(Beelen et al., 2013)
Sensitive to the number/
locations of sampling sites
Depend on selecting
meaningful predictors
Exposure misclassification
varies by pollutants
Cancels out any seasonal
variations and any peaks
PICTURES HAVE BEEN REMOVED DUE TO
CONFIDENTIALITY ISSUES
27. Proximity to major roads: 7 studies
No direct information on pollutants
Definition of a ‘major road’ can be
subjective and was highly
heterogeneous across studies
Does not consider compounded
effects of multiple roads or smaller
roads proximity
Exposure misclassification especially
when not considering vehicular mix/
traffic conditions
High potential of confounding
28. Monitoring stations data: 4 studies
Poor spatial distribution
and usually few road-side
monitoring
Cancels out any seasonal
variations and any peaks
as long-term averages
were always used!
Discrepancy between
subjects residential/ school
locations and locations of
monitoring stations
1 2
29. Dispersion modelling: 4 studies
Severe data demands
At the mercy of the emission factors
used in the model
Overestimates pollution during
periods of calm wind
1
33. NO2 measures of association
Exposure
assessment
method/ N
N of
measures
of
association
Exposure
associated
with
higher
odds of
onset
Ditto +
statistically
significant
NO2 levels
exceeding
WHO
guidelines?
Exposure
associated
with lower
odds of
onset
Ditto +
statistically
significant
Increase
interval in
exposure
(µg/m3)
Land-use
regression/ 7
17 16 4 No 1 0
10.3, 10.6,
7.2, 10,
10.4, 9, 10
Dispersion
modelling/ 1
4 1 0 Yes and No 3 0 19.6, 27.3
Central
monitoring/ 2
3 3 2 NA 0 0 18.8, 24.1
Diffusion
tube
monitoring/ 1
15 15 9 NA 0 0 11.6
39 35
34. PM2.5 measures of association
Exposure
assessment
method/ N
N of
measures
of
association
Exposure
associated
with
higher
odds of
onset
Ditto +
statistically
significant
PM2.5 levels
exceeding
WHO
guidelines?
Exposure
associated
with lower
odds of
onset
Ditto +
statistically
significant
Increase
interval in
exposure
(µg/m3)
Land-use
regression/ 5
14 14 7 Yes 0 0
3.2, 3.3,
4.1, 1, 3.2
Central
monitoring/ 1
2 2 0 Yes 0 0 9.7
16 16
35. Black carbon measures of
association
Exposure
assessment
method/ N
N of
measures
of
association
Exposure
associated
with higher
odds of
asthma
onset
Ditto +
statistically
significant
BC levels
exceeding
WHO
guideline
?
Exposure
associated
with lower
odds of
asthma
onset
Ditto +
statistically
significant
Increase
interval
in
exposure
(10-5/ m)
Land-use
regression/ 6
16 16 5
No
guideline
0 0
0.54,
0.58, 1.2,
1, 0.57,
0.5
16 16
38. Other observations
• Risk estimates were larger for girls (Shima & Adachi 2000, Shima et al.
2003, Oftedal et al. 2009, Clark et al. 2010)
• Positive associations with traffic-related air pollution were larger
for non-allergic asthma (Gehring et al. 2010, Gruzieva et al. 2013)
• Positive associations with NO2 winter-fall exposures were larger
than with NO2 summer exposures (Jerret et al., 2008)
• Non-movers had higher and significant risk estimates when
compared to movers (Gehring et al., 2010)
• Avoidance of house dust mites, pet allergens, environmental
tobacco smoke and encouragement of breast feeding protected
against the effect of air pollution (Carlsten et al., 2010)
40. Synthesis with other knowledge
• Indoor NO2 not associated with the onset of asthma (Shima and
Adachi 2000, Shima et al. 2002, Gauderman et al. 2005, Casas et al. 2012)
• NO2 may be acting as a surrogate of another pollutant/ mixture
• Ultra-fine particles (UFPs) are correlated with levels of NO2 and
NOx (Harrison 2005, Yahaya et al. 2012)
• UFPs offer a plausible link for a causal interpretation of these
results (Li et al. 2003, Xie and Wenzel 2013, Health Effects Institute 2013)
41. Synthesis with other knowledge
• Indoor NO2 not associated with the onset of asthma (Shima and
Adachi 2000, Shima et al. 2002, Gauderman et al. 2005, Casas et al. 2012)
• NO2 may be acting as a surrogate of another pollutant/ mixture
• Ultra-fine particles (UFPs) are correlated with levels of NO2 and
NOx (Harrison 2005, Yahaya et al. 2012)
• UFPs offer a plausible link for a causal interpretation of these
results (Li et al. 2003, Xie and Wenzel 2013, Health Effects Institute 2013)
• PM2.5 may be more potent than NO2 in asthma initiation
• But are the measures of associations real or spurious?
• Less is known about black carbon, could be a suitable metric
• PM the only pollutant regulated without regard to chemical form
(Bell, 2009)
42. Synthesis with other knowledge
Relative Particle Number, Mass, Black Carbon, CO Concentration versus
Downwind Distance from a freeway, source: (Zhu et al. 2002)
43. Conclusions
• Heterogeneous studies report rather consistent associations
• Results are likely to be due to chance, bias or confounding?
• Risk estimates differ by exposure metric and pollutants
• The nonsignificant results may be due to reduced power
• Although the risk estimates tend to be low, the population
attributable risk may be significant
• Exposure assessment methods continue to be a limitation
• Temporal variation and repeated exposures to short-term peaks
always lost through averaging of exposure – are they important?
• Many questions are left open
45. There is a need for integrating advanced
exposure modelling with adequately large
longitudinal studies, which can offer more
robust definitions of children’s asthma
46. Future work
Compliance,
effectiveness
Atmospheric transport,
chemical transformation,
and deposition
Human time-activity in relation
to indoor and outdoor air quality;
Uptake, deposition, clearance,
retention Susceptibility factors;
mechanisms of damage
and repair, health outcomes
Regulatory
action
Emissions
Ambient
air quality
Exposure/
dose
Human
healthChain of accountability (Health Effects Institute, 2003)
47. Future work
Compliance,
effectiveness
Atmospheric transport,
chemical transformation,
and deposition
Human time-activity in relation
to indoor and outdoor air quality;
Uptake, deposition, clearance,
retention Susceptibility factors;
mechanisms of damage
and repair, health outcomes
Regulatory
action
Emissions
Dispersion
Modelling
Exposure/
dose
Human
health
Human
healthChain of accountability (Health Effects Institute, 2003)
48. Future work
Compliance,
effectiveness
Atmospheric transport,
chemical transformation,
and deposition
Human time-activity in relation
to indoor and outdoor air quality;
Uptake, deposition, clearance,
retention Susceptibility factors;
mechanisms of damage
and repair, health outcomes
Regulatory
action
Emissions
Dispersion
Modelling
Exposure/
dose
Human
health
Human
healthChain of accountability (Health Effects Institute, 2003)
50. 0
0.001
0.002
0.003
0.004
0.005
0.006
0 20 40 60 80 100 120 140
AVERAGEPM(GRAMS/KM)
AVERAGE SPEED (KM/HOUR)
PHEM data COPERT
0
0.001
0.002
0.003
0.004
0.005
0.006
0 20 40 60 80 100 120 140
AveragePM(grams/km)
Average speed (km/hour)
PHEM data 1st new function data 2nd new function data COPERT
51. Future work
Compliance,
effectiveness
Atmospheric transport,
chemical transformation,
and deposition
Human time-activity in relation
to indoor and outdoor air quality;
Uptake, deposition, clearance,
retention Susceptibility factors;
mechanisms of damage
and repair, health outcomes
Regulatory
action
Emissions
Dispersion
Modelling
Exposure/
dose
Human
healthChain of accountability (Health Effects Institute, 2003)
53. Future work
Compliance,
effectiveness
Atmospheric transport,
chemical transformation,
and deposition
Human time-activity in relation
to indoor and outdoor air quality;
Uptake, deposition, clearance,
retention Susceptibility factors;
mechanisms of damage
and repair, health outcomes
Regulatory
action
Emissions
Dispersion
Modelling
Exposure/
dose
Human
healthChain of accountability (Health Effects Institute, 2003)
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