W2 Air Pollutions Measurements in Singapore Flashcards
what does AQI stand for
air quality index
air pollutants used in the determination of AQI
sulfur dioxide
nitrogen dioxide
ozone
carbon monoxide
particulate matter (PM10 and PM2.5)
what does PSI stand for
pollutant standards index
only sg still uses it
same air pollutants measured but value is always lower than AQI
what is particulate matter
airborne particles
not made up of a unique or single substance
mixture of organic, inorganic, and biological materials of various sizes and shapes
may have other substances bound
composition varies regionally, seasonally and daily
what are the problems with PM measurements and AQI
trying to assign exact health effects relating to levels of PM is fraught with uncertainty and has huge errors
the AQI scale does not take into account what the particles are made of
It is not clear what is the time scale (chronic or acute) for the ill effects of the AQI scale
no error analysis is reported
what are 3 other compounds that are hazardous but not measured routinely
polycyclic aromatic hydrocarbons
volatile organic compounds
dioxins
what is the enrichment factor
used to determine the effect of non-crustal elements on observed concentrations of elements
elements with EF < 10: assumed to originate from crustal erosion (biogenic)
10 <EF < 100: moderately enriched by anthropogenic (unnatural) sources
> 100: related to industrial, incineration and automobile emissions
how are PM samples prepared before analysis by atomic spectroscopy
samples collected on filter papers > digested by microwave assisted acid digestion to fully dissolve the PM > analysed by inductively coupled plasma spectroscopy
