Lecture 6/7: air quality 1 & 2 Flashcards
What are pollutants in the air?
Substances present at concentrations above their normal ambient level. Anything in atmosphere higher than reliable standards.
Explain what the atmosphere consists of and how it works
atmosphere consists of several layers, divided in layers according to major temperature changes. Gravity pushes layers of air down on the earth’s surface. –> air we breathe at sea level has higher density than air on the highest mountain.
Name anthropogenic sources of air pollution.
- Burning of fossil fuels, incineration/combustion/biomass
burning, vehicle emissions, waste decomposition - Stationary sources – smock stacks, waste incinerators
- Mobile sources – vehicles, marine vessels, airplanes, fumes
- Agriculture – pesticides, insecticides, fertilizers
Name natural sources of air pollution
- volcanoes, wildfires (exacerbated by cc), VOCs from plants, dust
- sea spray - washes pollutants out of the air BUT since it a
source of PM - mostly salt that is whipped into the air by strong
winds – it can also contribute to air pollution - Methane from livestock manure
What are different types of pollutants?
Primary pollutants: harmful chemicals emitted directly into the air from
natural processes and human activities.
Secondary pollutants: primary pollutants react with one another and with the basic components of air to form new harmful chemicals.
How does carbon dioxide become a pollutant? natural and anthropogeni?
Natural: thunderstorms
Anthropogenic: high temperature combustion, motor vehicles, power plants.
How does particulate matter get into the air /become a pollutant?
Natural: dust storms, ash from volcanoes, wildfires, se spray salt
Anthropogenic: burning of fossil fuels in vehicles and power plants.
What is the function of good ozone?
- reduction of radiation by absorption
- removes almost all incoming UV
Bad:
* damage to ‘good ozone’ by GHGs leads to high levels of UV.
* UV is harmful, causing skin cancers, genetic damage and climate change.
Ozone concentrations are the highest in the midday. Why?
Most sun light/UV-radiation
What does ozone consist of?
Light and heat from the sun + nitrogenoxide (NO2) + Volatile organic compounds (VOCs).
What is smog?
Smoke + fog. consists of ozone, nitrogen dioxide, hydrocarbons and other gases combined with solar radiation to form photochemical smog.
How does Acid Deposition work?
Emission of primary pollutants –> transported –> forms secondary pollutants –>acid rain (deposition) –> Eutrophication/deforestation
What causes acid rain?
release of acidic gases into the atmosphere. Gases react with water, oxygen and other chemicals to become sulphuric and nitric acid to from acid rain.
What does a low pH mean?
more acidic.
What are effects of acid deposition on vegetation/humans and infrastructure/aquatic system?
Vegetation:
- loss/leakage of nutrients
- corrodes protective layer of wax on leaves.
- Damage to stomata
Humans and infrastructure:
- Acidic water liberates mercury from the soil
- Agricultural food production
- Poor water quality
Aquatic system:
- High aluminium levels - highly toxic
- Fish eggs cannot hatch at low pH
- At lower pH levels, some adult fish die
Why does transboundary transport occur?
Because pollutants have very low deposition velocities and secondary pollutants need time to develop.
How are aerosols removed?
Aerosols are removed by wet (rain) and dry deposition
WHat is the grasshopper effect?
Atmospheric distillation that transfers pollutants to the poles. When compounds that help dilute pollutants evaporate from the ground surface and is deposted in other places.
What is the Asian Brown Cloud?
Giant brown cloud hanging over much of south Asia. Consists of two types of climate pollutants: partuclar matter & gases (ash, dust and smoke).
What are effects of the asian brown cloud?
- poor air quality
- dimming: areasols prevent radiation from the sun while others send sunlight back into the atmosphere.
- reduces surface temperatures
- Less evaporation
- affects cloud formation
- changes rainfall patterns
How does air move? Include outdoor and indoor in your answer.
outdoor:
* lgobal, large scale atmospheric circulation between atmospheric layers
* Regional - between high and low air pressures
* Local, different temperature between air and sea
Indoor:
* inside, influences temperature humidity and pollutant movement
* Natural ventilation systems
* Mechanical ventilation systems.
What is global circulation
It is a consistent pattern to how air moves around our planet’s atmosphere. It is caused by the sun that heats earth more at the equater than at the poles. Result is warm light air in the tropics / heavy air near poles.
How does regional circulation work? what is it?
- temperature is regulated by the energy balance of the earth
- lapse rate affects the movement of air/stability.
Local variation? how does that work?
A local windsystem characterized by the movement of warm and cool air between land and water.
Induced by differences that occur between the heating or cooling of the water surface and the adjacent land surface.
