Lecture 17 Respiratory Toxicants/Air Pollution

overview of air pollution

-global and local problem

-1/9 global deaths

-1000 deaths in MTL and TOR due to smog

-air quality monitoring systems all over Canada to check daily air quality

-kills more Canadians than car accidents per year

-13 ppl die a minute in the world from it

lung structure

-huge surface area and blood supply to exchange gasses, due to this design can take in other things besides CO2 and O2

-ex// nicotine, anesthetics, toxicants

bronchus

-has epithelial, muscle and cartilage layer

-epithelium has both collated and goblet cells

-together mucus and cilia cells work together to generate the mucociliary escalator

-goblet cells release mucus which traps contaminates

-escalator may be impaired by air pollutants

-the bronchioles branch out from the bronchus

alveoli and mucociliary escalator

-alveoli have thin walls for gas exchange

-alveolar macrophages patrol lungs for microorganism and pollutants and consume them they then rude the mucociliary escalator and become deposited into the GI tract

-large particles are trapped and removed by escalator in large airways

-small particles reach peripheral alveoli where it may enter blood circulation

history of air pollution im gay

-babies are most vulnerable bc they don’t have fully developed immune system,

-air pollution became major issue following the industrial revolution which promoted widespread coal use

-during the great smog of London 4000 ppl died in a few days

-clean air laws were then passed to limit coal burning in fireplaces

-death was related to levels of sulfur dioxide and smoke

-warm air current settled above city trapping smog from being blown away 8created air inversion)

-with smog came very low visibility making getting around hard

sources of air pollution

-natural sources like volcanoes and wildfires

-manufactured, fossil fuel, airplanes, factories, generating electrcity

morbidity and mortality

-8 mil a year

-sources of mortality vary by region

-north America: due to power production, car use and agriculture

India: indoor cooking

harm from air pollution

-effects CV, respiratory, kidneys, brain

major health issues include:

'-ischemic heart disease

cerebrovascular disease

-lung cancer

-COPD

-infections and respiratory disease deaths are seen in children 18% under 5, 11% over 5

nitrogen and sulfur oxides

-can react with other comments of atmosphere to form N and S acid

-mixing of these with water can lead to acid rain

-acid rain can affect soil pH making farming harder

-it is corrosive which puts historical monuments in danger

SO2

-water-soluble irritant gas that triggers airway nociceptors

-produced by coal and is absorbed in upper airways

-causes bronchoconstriction due to cell injury and mucus secretion due to goblet cell proliferation

-can cause acute or chronic bronchitis

NO2

-comes from gas heaters, stoves, smog, side stream of Tabacco smoke

-farmers make be exposed due to silage

-airway injury is similar to ozone

CO

-forms carboxyHb

-effects living organisms and is corrosive to structures like marble and limestone

smog and outdoor air pollution

-biggest source is vehicle exhaust, powerplants, fires

-smog is combo of smoke and fog formed by a photochemical rxn of combustion of smoke in the air

-it is a light-dependent rxn so more is found in summer

-car use prevalence will also increase its levels

USEPA air quality standards for ozone, PM, SO2, NO2 Co etc

components of smog: ozone

1) ozone

is generated thru rxn of radical O atom with O2 molecule

sunlight & NO2 = release of free O atom

sunlight catalyzes the rxn, conc is highest in the northern hemisphere during summer

-ground level or inner level ozone layer is different from upper

-located in stratosphere protects earth from damaging UV rays

-ozone located in troposphere is bad can cause damage to lungs and plants

-fortunately, its levels have remained stable in Canada

ozone injury

-lung damage, decreased lung function