Week 5 Flashcards
(35 cards)
Air pollution throughout human history
Fire = air pollution
- evidence of habitual use of fire 300,000 to 400,000 years ago
- thus air pollution has been an issue at the “household” level for hundreds of thousands of years
- urbanisation
Air pollution regulations in England
- clean air act of 1956 and amendments of 1968 (partly in response to 1952 pollution event that killed thousands)
Urban air pollution vs development
Low to high (development)
- start of industrial development -> initiation of emissions controls -> stabilisation of air quality -> improvement of air quality (this part the development is over halfway to high and air pollution concentration is going down) -> high technology applied -> WHO guideline or national standard (high development and low air pollution concentration)
Changes in energy sources - coal to gas
coal is a dirty polluting fuel
- in late 1950s coal use decreased (due in part cause of Clean Air Act of 1965) as oil use increased
- abundance of natural gas starting in the late 1960s and ‘oil crises’ of 1970s led to widespread use of gas for heat and power generation
Significant improvement in air quality (in high income countries)
Sulphur dioxide and smoke were super high in 1950s and now are very low 2000 HOWEVER, though they are lower the level in 2000 is still bad and has adverse health effects
PM Sizes
PM = particulate matter
- liquid or particles floating around in the air
- range in size
- concerned with the smallest particles usually 2.5 micro meter
- PM 2.5 - combustion particles, organic compounds, metals, etc.
- PM 10 - dust, pollen, mold, etc
- particles that are larger and have more can interrupt light (makes outside look foggy in a sense) = a lot is bad and impacts visibility
- size is linked to adverse health effects therefore smaller particles are worse because they can squeeze into different airways of our body and impact us internally
- large particles stop at the nose while small particles reach the alveoli and deposit there
PM sizes and concentrations video
- PM concentrations are typically expressed as the mass of particles in a volume of air
- when we describe PM concentrations we must also describe the particle size
PM 2.5 Concentrations in Canada
- we are doing pretty well with the levels
- still a bit high for WHO to be considered safe
- PM higher in very urban places like major cities, Vancouver, Calgary, Edmonton, Toronto, etc.
Ozone
good up high, bad nearby
Good up high - ozone layer, which absorbs harmful UV radiation from the sun
Bad nearby - formed when pollutants (e.g., vehicle emissions) react with sunlight, bad for health
traffic-related air pollution
- mixture of particles and gases that seems to have particularly damaging effects on human health
- the specific agent(s) responsible for the health effects has not been definitively identified
- pollution from cars have very large spatial gradients
- particles are high in the middle of the road but with wind it will make it lower depending whether you are on upwind or downwind
- upwind is higher but downwind is low
PM 2.5 burden of disease
a large portion of the burden of disease from PM 2.5 comes from its impact on cardiovascular health
Health impacts of ambient air pollution - even in high-income countries
estimated of annual premature mortality attributable to ambient air pollution:
- GBD: ~4000
- health Canada: ~15000 ($120 billion total economic cost of all health impacts, 6% of GDP)
Controlled animal exposure studies
Long-term air pollution exposure and acceleration of atherosclerosis and vascular inflammation in an animal model
- hyperlipidemic mice (prone to atherosclerosis in the arteries)
- randomised to receive “high fat” chow or “normal” chow and PM2.5 or filtered air
- composite plaque area in PM 2.5 exposed group greater than among exposed to filtered air
Air pollution epidemiology - time series studies
- use daily data on air pollution, mortality counts, and meteorology
- relatively simple, easy, inexpensive
-> 1000s of studies
-> cities with a wide range of population and air pollution characteristics
-> consistent associations between air pollution (PM) and mortality
Is living near traffic bad?
- Yes, the risk of cardiopulmonary mortality for living near traffic relative to not living near traffic is about a 20-30% increase/difference
What level of IARC is air pollution and PM?
The IARC classified air pollution and PM as carcinogenic to humans (Group 1)
- air pollution is now considered the most important environmental carcinogen (more important than second-hand smoke)
- air pollution definitely affects the cardiovascular system
Effects of PM in the body after exposure
Particulate matter exposure -> particle deposition in airway -> translocation of particles into blood stream OR -> airway inflammation -> systemic inflammation
health impacts of air pollution
established effects:
- shorter life
- stroke
- heart disease
- asthma
- lung cancer
- reduced lung function
- low birth weight
- diabetes
Possible effects:
- cognitive development
- cognitive decline
- mental health
- obesity
- birth defects
developmental programming
Refers to how early-life exposures (pregnancy or early childhood) can permanently influence health and disease risk later in life.
Factors that influence:
- maternal nutrition
- maternal disease
- environmental exposures
- stress
- maternal lifestyle
These developmental programming can lead to psychologic adaptations:
- reproductive system
- metabolic system (insulin resistance, glucose intolerance, etc.)
- cardiovascular system
- cognitive functioning
air quality management progress
while aggregate emissions (six common pollutants) decreased, GDP increased a lot (this is good cause our economy was good), vehicle miles traveled increased, population grew a bit, energy consumption grew a bit, CO2 emissions grew a bit but maintained spot
- this proves that we can tackle environmental problems while also managing a good and high GDP (gross domestic product) - people think we cant have both
- wildfire smoke has influenced trends in average annual PM 2.5 concentrations
What happens when we remove the pollution?
- 10ug/m3 reduction in PM 2.5 associated with average 0.6 year increase in life expectancy
- air pollution reductions accounted for up to 15% of total life expectancy increases in study areas
household air pollution
air pollution caused by the indoor burning of unprocessed solid fuels, including:
- charcoal
- wood
- crop residues
- dung
- coal
Feels are burned indoors, in open fires or poorly functioning, poorly ventilated stoves
energy vs development - the energy ladder
progression of energy sources that households and communties use from tradtional to more modern forms of energy sources.
- example: coal to natural gas
emissions by fuel type
- dung is super high
- crop residues is lower but second highest
- wood is getting lower
- kerosene is pretty low
- gas is super low
- electricity is none cause there’s no emissions but there is still PM10
