ESCI 274 Lecture 5: Atmospheric Changes

Pathways for climate change to impact health (similar to primary, secondary, tertiary) 

1. Directly through weather variables such as storms 
2. indirectly through natural systems such as disease vectors 
3. pathways heavily mediated through human systems such as undernutrition.

Earth’s early atmosphere

• Early atmosphere

  • Evolution of blue-green algae

  • Photosynthesis reduces CO2

  • O2 first tied up in rock cycle 

  • Rock O2 reservoirs saturated = free O2

  • ~20% O2 optimal for life

  • UV an issue

  • Genetic materials of cells (DNA) susceptible to damage by UV light at certain wavelengths (~25μm)

Earths atmosphere: Atmospheric Oxygen

• Atmospheric Oxygen
  • Multiple mechanisms to balance O2
  • Respiration - Photosynthesis
    • Combustion (i.e. forest fires)

Earths atmosphere: Ozone

• Ozone
  • In order to photosynthesize, organisms need access to sunlight, but also protection from UV radiation

 Permafrost link to atmosphere

• Warming → permafrost thaw → greenhouse gas emission → warming → 
• “Permafrost will make it even harder to meet our emissions targets 

Air Pollution

Chemicals added to the atmosphere by natural events or human activities  in high enough concentrations to to be harmful 

Types of air pollution

1. Particulate matter
2. Fires 
3. Carbon monoxide 

Health impacts of air pollution

1. Low level exposure

• Irritates eyes
• Causes inflammation to upper respiratory tract 
• Can develop to chronic respiratory issues

1. High level acute exposure

• Severe illness or death 

1. Impact depends on 

• Types of pollutants
• Pollutant concentration, duration of exposure
• Individual susceptibility 

Air quality around the world

• 91% of the worlds population lives in areas with poor air quality (ambient) 
• Total annual number of deaths by risk factor - air pollution = 6.67 million

Climate, air pollution, Covid impact

• Initial covid impact: dramatic fall in air pollution 
• Exposure to low levels of air pollution increases covid-19 risk 
• Air pollution and climate change: Allergens

= increased asthma and allergic respiratory issues

= increased allergic rhinitis 

= increased conjunctivitis 

= increased dermatitis 

= increased ambulance calls for asthma and hospital visits for rhinitis 

• Children are very susceptible 

Atmospheric future (IPCC projections)

• Dimming (earth reflecting less albedo, earthshine illuminating moon decreased from 1998-2017
• Climate change will affect future air quality (photochemical oxidant yes, fine particulates unsure) 
• Increased urbanization, solid biomass fuels, industrial development in the absence of emission controls (all lead to O3 production (precursors), many lead to PM release 
• Increased temperatures: expected to increase air pollutants effects (Canada/ USA mortality rate due to O3 expected to increase) 
• Acute air pollution episodes: increased temperatures and droughts will increase wildfire incidents, particulate matter
• Aeroallergens: increased temperature, generally projected to increase production and release of airborne allergens (pollen, fungal spores), increase associated with respiratory illness
• Changes in wind and precipitation patterns may increase problems 
• Summertime ozone is projected to change non-uniformly

Co-benefits of Reduction of Co-Pollutants

1. Improvement in energy efficiency will decrease CO2 and health damaging pollutants, provided energy demand does not increase (or is offset by carbon neutral sources). 
2. Increase in combustion efficiency will decrease incomplete combustion products, this is positive regardless of energy efficiency change. 
3. Increased use of non-combustion sources (wind, solar, tidal, wave, geothermal) will reduce emissions of CAPs and health damages. 

Air pollution diagram

Classifying pollutants diagram

Signs of carbon monoxide poisoning diagram

Why smog is harmful diagram

Air pollution and climate change diagram

Climate change and volcanic eruption diagram