enviro 200 - test 2
black carbon/soot
PM2.5, pollutants that contributes most for climate change, produced from incpmplete combustion of fossil fuels/wood/other fuels
nitrogen oxide & its effects
fuel burnt at high temp, regulated pollutant, respiratory systems get affected
carbon monoxide & its affects
petrol vehicles/ gas cooktops/heaters, reduces O2 delivery to body, headaches/tiredness , visual impairment, performancd affected, high exposure = death,
ozone & its effects
secondary pollutant, lung diseases, produced from reaction between emissions & VOCs
sulphur dioxide
burning of fossil fuels ie coal and oil, w water makes sulfric acid (acid rain), respiratory system and eye irritation effects
VOC
variety of chemcial compounds
what would reduce thr rate of climate change
decrease in black carbon
compliance monitoring
long term, continuous
diffusion tubes
low cost, general indication of levels over seevral weels, highlighting hot spots
deposition monitoring
finds microplastics
concentration
how much pollutant there is
exposure
concentrations of pollutant whete person is
dose
exposure & breathing rate & time period
uptake
dose & how much pollutant remain in body
dose equation
dose = CO x commute time x exercise factor
ppm x h
occupational air pollution issues
airborne substances contirbute to ~80% of work related health issues
lack of knowledge and awareness
uncertainty of how to mitigate and reduce exposures
common carcinogenic (cause cancer) exposures
benzene, solar UV, ocular UV, diesel engine exhaust, tobacco smoke, wood dust
occupations w high exposure
miners, chefs, drivers, railway, construction,tunnel
ways to reduce exposures
management plan, toolbox talks to raise awareness, rotating shifts, reduce # hours, respiratory protective equipment
advantages/pros of Steady-State Gaussian Plume Models
been using for decades, simple input requirements, easy to use
disadvantages/cons of Steady-State Gaussian Plume Models
limited in scope and results
light wind conditions not good
not applicable in regional scales/complex terrain/changeable meterorology
particle settling chambers
removes large particles from gas streams, precleaner, cheapest
cyclones
centrifugal forces to separate particles, diamater determines particle removal size
electrostatic precipitators (ecps)
high efficiency, electrodes used to create field, particles become negatively charged and attach, larger particles have higher charge
fabric filters/bag houses
cylindricalnbags to trap particles, vaccum cleaner, shake to remove particles, bag life , small size/high efficiency/filters small particles,
cons - cant process wet gas stream, oily particles not good, cant do high temp
gas pollution reduction techniques
absorption/scrubbers, adsorption, oxidation, NOx control
absorption/scrubbers
use liquids to remove gaseous pollutants, spray liquid into gas stream
adsorption
gas passes thru solid, removed VOCs, diffuse, 90% removal efficiency
oxidation
at high temps VOCs can be oxidised to form CO2 and water vapour, maximise combustion time/temp/turbulence
NOx control
cant be removed using liquids, readtsd w ammnonia to form N
more expemsive/complicated is selected catalyst reduction(SCR)
mitigating air pollution
difficult to reduce air pollution after emissions, harder w larger space, reduce emissions at source, reduce amount of emissions
atmospheric disperion models
simulation of physics/chemistry for transport/dispersion and transformation of pollutants
estimating air pollution conc
what are atmospheric disperion models used for
air quality guidelines
new facilities planning
manage existing emissions, identifying sources
risk management
save money
stages pf modelling process
Data input, data processing, data output, data anaysis
things to consider abt pollutant source
emission rate, height of emission, temperature of emission, exit velocity of emission
note:
emission rate = amount of fuel
hotter temp = released higher in the air
low velocity = higher concentration
atmospheric stability
worst : fumigation and looping, better : fanning, coning, lofting
pros for lagrangian models
range of different scales and sources
non steady state
can handle complex terrain and atmospheric chemistry
complex
good in low wind speed conditions
more common
cons of lagrangian models
more training required and high computing power
particulate control devices (reducing particle emissions)
settling chambers, cyclones, ESPs, fabric filters/baghouses
how does black carbon contribute to climate change?
- absorbs sunlight and converts it to heat
- accelerates melting of snow/ice
- prevents clouds from being formed
-
What are the impacts of noise?
- accoustics
- occupational noise exposure
- community noise
Power in watts vs Power in dB
Power in Watts = absolute
Power in dB = relative
Major sources of air pollution?
- Vehicles
- Construction
- Cigarettes
- Industry
- Natural Sources
- Bush fires
- Home heating and indoor cooking
Reactions of individuals to a sound/noise depends on...
- age
- time of day
- nature of the source
- individual noise sensitivity
- acitivity
- control over the noise source
- perception of noise
- level of hearing
Where to monitor noise?
- motorways
- airports
- residential/business activities
- construction
- entertainment places
Considerations in the deisgn of noise barriers
- aesthetics
- height
- safety
- material
- angle (sound propagation)
Noise impacts on health and wellbeing?
- annoyance
- sleep disturbance (-> mental health)
- concentration
- communication
What is Masking?
Pleasant sound to cover up unpleasant sounds (water fountain etc)
Air exposure assessment variables:
- concentration
- exposure
- dose
- uptake