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41 Cards in this Set
- Front
- Back
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What are VOC's and what is special about them and where can they come from
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Volatile Organic Compounds
Can be decomposed into CO2 and H2O by UV light and catalyst Can come from fuel combustion, wastes, burning, animal |
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What is PM
where is it from |
Particulate Matter - mass of solid or liquid dispersed in air
Fuel combustion, incinerators, mining, burning, waste |
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What is the general combustion equation
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CmHn+(m+n/4)O2 = mCO2+n/2h20
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What are the 4 most dangerous indoor pollutants
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Tobacco smoke, Formaldehyde, radioactive radon 222 gas, very small fine/ultrafine particles
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Define: Indoor Air Quality, Good IAQ
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Nature of air that affects health/well being of occupants
Air which is free of pollutants that cause irritation, discomfort or ill health |
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What are three causes of indoor air quality issues
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Release of pollution from indoor sources
Inadequate ventilation to dilute pollutants Inadequate filtration to remove pollutants/PM |
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name the six types of major indoor air pollutants
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Inorganic gases: NOx, O3
Organic Gases: CO, CO2 VOCs micro-organisms Radon (Rn) Respirable suspended particulates (RSP) |
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Outline the 8 steps for coal combustion calculations
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1) find moles of each species = m/M
2) find O2 required = Sum all the above (remember to halve n(H2) - n(O2) in feed 3) Find air required = above/0.21 4) Multiply by excess % 5) Find N2 and O2 after combustion = in - reacted (for O2 minus the initial amount in feed as well) 6) Find flue gas (CO2, H2O, SO2, N2 and O2) 7) total moles 8) Find percentage in flue gas |
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Name 3 Stationary outdoor emission sources
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Power Generation
Domestic Dwellings Industry |
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Name 2 mobile emission sources and their emissions
Which is worse? |
Petrol (CO, VOCs, Pb, NOx)
Diesel (NOx, VOCs, PM) |
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List 7 outdoor air pollutants as a result of industry
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Suspended particulates
Sulphur Dioxide Nitrogen Dioxide Carbon monoxide VOCs Pb O3 |
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how much is one Ci and one pCi and what is it
what is the maximum conc for radon what is dangerous about radon |
one Ci is one curie and is the radiative power of 1 g of pure radium defined as 3.7e10 nuclear disintegrations per second
pCi is one pico curie and is equal to 1e-12 Ci 4 pCi/L Lung cancer |
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What are the two methods of air pollutant measurements and explain them
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Ambient Monitoring: Concentration of pollutants in the air the public breathes are measured
Source Monitoring: concentrations and emission rates from air pollution sources are measured. |
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Where should an ambient sampler be generally placed?
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Located in a place where the public has free access where the pollutant concentration is the highest
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What is isokinetic flow and when must it occur
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Occurs when the velocity in the probe is the same as that of the gas in the stack. Needs to occur so that a the true conc matches the measured conc
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Formula for C avg in a stack?
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Cav = Total mass/Total Volume = Sum of v*A*c/Sum of v*A
where v = velocity, A - area, c= concentration |
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Name a well defined source and one that isnt well defined
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well: power plant
not: unpaved road, forest fire |
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How are gas and solid samples taken?
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Gas: evacuated cylinder or sampling bag
Solid: adsorbents (carbon, silica) extraction or desorption |
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name and explain the two types of modelling methods
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Source oriented: given source characteristics and data, estimate pollutant concs at the receptor site
Receptor Oriented: Given pollutant conc at receptor site, estimate contributions of the sources. |
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Equation for Air mass ratio?
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AF=massair/massfuel
use m=n.M and take the fuel basis as one mol |
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What is a volume mixing ratio
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molecule of gas per molecule of dry air or
mass of gas per mass of dry air or conc of gas per conc of dry air(use density?) |
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What is the simple box model eqn?
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c(leave) = b(in) + qL/uH
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How can sulfer be present in fuel
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Chemically bonded S
as crystal iron pyrite (FeS2) |
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Name and explain the 3 combustion methods to produce NO
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Thermal: Oxidation of N2 at high temps (>2000K)
Prompt: Highly reactive species E.g. CH3 from fuel interact rapidly with N2 and O2 (Carbon needed) Fuel: formed by conversion of some of the nitrogen originally present in the fuel to NOx. |
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How does the zeldovich mechanism work? give 3 eqns
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at high temps, H, O , N, OH radicals form and they can reacto to produce NO.
O +N2 = NO N + O2 = NO + O N +OH = NO +H |
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How to calc stoich A/F ratio?
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recall combustion eqn
((x+y/4)*(M(O2)+(0.79/0.21)*M(N2)))/( 12x+1y) |
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Are concs usually higher indoor or outdoor?
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indoor
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Name 5 indoor air poll sources
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smoking lounge, animals, pesticides, sick people, eating areas
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What is the steady state eqn for indoor box model
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c = c(in) + (S(source emission rate)-R(sink))/Q(air flow rateIn-out)
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What is the unsteady state eqn for indoor box model
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Vdci/dt=Q(c0-ci)+S-R
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name in order of effectiveness, the strategies to reduce indoor pollutants
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Source control, ventilation, Air cleaner
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name and explain the two types of ventilation
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Natural - due to wind, or temp differences
Mechanical - air conditioner |
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name two methods of source control
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prevention and cleanup/dilution
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Name 3 types of air cleaning practices
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Gas: Absorption/adsorbtion
Paricle: Filtration |
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What is the equation for fractional reduction in emission rate
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q2/q1 = (c2-b)/(c1-b)
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What is the wind speed correction eqn?
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u2=u1(z2/z1)^P
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When given time, how to find cav
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cav = 1/(60) * sum(conc*v)
or do the mass/vol |
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name 3 non destructive detectors
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Thermal conductivity
Electrocapture Photo ionization |
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name 3 destructive detectors
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Mass spectral
Flame ionization flame photometric |
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What is a TCD used for and how it works?
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To sense changes in thermal conductivity and comapres it to a reference flow of carrier gas. used for COx and NOx
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How is NOx, SOx, O3, CO
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NOx converted to NO, react with ozone and read UV, then compare to parallel sample
SOx find UV emission, then can get conc O3 UV absorption analysis CO use Infrared and beers law |
