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30019- Molecules to Materials: deconstructing the environment > Atmosphere- 2 Air pollution > Flashcards

Atmosphere- 2 Air pollution Flashcards

1
Q

What must happen with the reactants when a chemical reaction occurs?

A

Come together
In correct orientation
Enough energy (activation energy)

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2
Q

What does activation energy lead to?

A

temperature dependence

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3
Q

What happens to most reactions as they get hotter?

A

Get faster

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4
Q

Where does the energy come from for photochemical reactions?

A

Sunlight

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5
Q

What are thermal reactions driven by?

A

energy possessed by reactants

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6
Q

How do you calculate the rate of change of concentration?

A

Rate Law x stoichiometry

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7
Q

What does stoichiometry tell us?

A

relative numbers of reactant and product species destroyed / created per reactive
encounter

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8
Q

What does the rate of a chemical reaction tell us?

A

the rate of change of concentration of reactants or products

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9
Q

What does Rate Law tell us?

A

how/what the rate depends on

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10
Q

What is the rate of reaction like for an elementary reaction?

A

proportional to concentration of all reactants

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11
Q

What is the equation for temperature/ temperature dependence?

A

k= A exp (-Ea / RT)

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12
Q

What do the letters in the temperature dependence equation mean?

A

A= pre-exponential factor
Ea= activation energy (Joules per mole)
R= Gas constant
T= temp in Kelvin

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13
Q

What will the equation be like if there is positive temperature dependence?

A

Ea is positive
Rate constant increases with higher temp

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14
Q

What will the equation be like if there is negative temperature dependence?

A

Ea negative
Rate constant decreases with higher temp

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15
Q

What has happened to air quality in the UK since 1950’s?

A

substantially improved

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16
Q

How does the UK’s current air quality affect the life of the human population?

A

34,000 deaths/yr
4-6 month life expectancy reduction

17
Q

What is the economic cost per year of the air quality?

A

£20bn

18
Q

How many global deaths are there resulting from air quality per year?

A

8 million

19
Q

How much of people living in urban areas live with air quality worse than WHO guidelines?

A

80%

20
Q

What does ground level cause significant damage to?

A

plants

21
Q

How does ozone damage plants?

A

enters the leaf through stomata, and attacks cell membranes, reducing plant health & growth / yield

22
Q

What losses does ozone have on global crop yield?

A

5-12%

23
Q

What are 2 key air pollutants?

A

NOx
Fine particles (PM2.5)

24
Q

What are the sources of NOx?

A

Local road traffic (60%)
Road traffic background (18%)
Homes, industry and commerce (9%)
Regional background (8%)
Non-road transport and mobile machinery (5%)

25
Q

What is the make up of the local road traffic source of NOx?

A

Biggest is diesel cars with other diesel vehicles being the biggest contributors

26
Q

When a NOx concentration map is put of the west midlands what image do you get?

A

highest concentration map out road systems

27
Q

How does concentration of NO2 change throughout the day?

A

Peaks when there is both rush hours
(UoB peak later as people work till later at uni)

28
Q

What are some of the sources of PM2.5?

A

Road traffic
Power generation
Aircraft
Agriculture
Shipping
Home (cooking)
Industry

29
Q

What does the longer lifespan of PM2.5 mean?

A

areas will all have similar concentrations thus concerted local, regional and national action needed

30
Q

What type of pollutant is ozone?

A

secondary pollutant formed in atmosphere

31
Q

What is the formula for the formation of ozone?

A

VOC + NOx + sunlight = Ozone (O3)

32
Q

Why can ozone be a transboundary pollutant?

A

VOC and NOx emissions might be quite far upwind

33
Q

What is the formation timescale of ozone?

A

days-weeks

34
Q

What is ozone formation exacerbated by?

A

fine weather
Sunshine
Airmass from Europe (UK formation)

35
Q

What are the UKs air quality objectives for NOx and PM2,5?

A

NOx= 40 ug/m3 - Annual Average
PM2.5= 10 ug/m3 Annual Average, by 2040

36
Q

What are the WHO guidelines for NOx and PM2.5?

A

NO2= 10 ug/m3 Annual average
PM2.5= 5 ug/m3 Annual average

37
Q

What has Birmingham done to reduce NO2?

A

Created the bham clean air zone
Offending cars- £8 per day
HGV- £50 per day

30019- Molecules to Materials: deconstructing the environment (29 decks)

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