Air monitoring. Air pollution. Pollutant types. Installations for air monitoring

1. Air monitoring. Air pollution. Pollutant types. Installations for air monitoring.

2.

Air pollution
• The presence in atmosphere of one or
more contaminants in such quantities and
of such duration as is or tends to be
injurious to human health, animal or plant
life, or property.

3.

Air pollution – the problem
• Global
• Regional and urban
• Local
• Indoor (homes, factories, offices)

4.

Air Pollutants Types
Pollution can be grouped into two categories:
(1) primary pollutants, which are emitted directly
from identifiable sources, and
(2) secondary pollutants, which are produced in
the atmosphere
when certain chemical reactions take place among
primary pollutants.

5.

Primary Pollution
• The major primary pollution include:
particulate matter (PM),
sulfur dioxide,
nitrogen oxides,
volatile organic compounds (VOCs),
carbon monoxide, and
lead.

6.

Secondary Pollution
Atmospheric sulfuric acid is one example of a
secondary
pollution.
Air pollution in urban and industrial areas is often called
smog.
Photochemical smog, a noxious mixture of gases and
particles, is produced when strong sunlight triggers
photochemical reactions in the atmosphere.
The major component of photochemical smog is ozone.

7.

Effects of human activities on the atmosphere
(NSW SOE 2000)

8.

9.

10.

Controlling Air Pollution through
Regulations
Regulatory efforts to control emissions
include setting of
standards for four of the primary pollutants—
particulates,
sulfur dioxide,
carbon monoxide, and
nitrogen
as well as the secondary pollutant ozone.

11. Note!

• when air pollution episodes take place,
they are not generally the result of a
drastic increase in the output of pollutants;
instead, they occur because of changes in
certain atmospheric conditions.

12.

Emission sources. Typical parameters of the
point source:
• emission intensity (E)
• geometric height of the source (h)
• stack diameter at the source exit (d)
• gas velocity at the source exit (v)
• gas temperature (T)
• stack localization in the geographical
coordinate system (x, y)

13.

Ambient air quality monitoring in urban microenvironments
such as sidewalks, bus stations,
parking garages, under different climate conditions
- Slater Street, Ottawa

14.

• Ambient sampling stations constructed at ETC for
roadside measurement of VOC, PM2.5, and carbonyl
compounds

15.

Air quality monitoring
Methods and instrumentation
Gas measurement using spectroscopic methods
Spectrophotometry is based on the interaction of the gas molecules with light.
hc
Absorbtion techniques – it is measured the intensity of light after passing through
a gaseous medium. Usually absorption is measured at several frequencies in order to
avoid offests and interferences with other species. There are 4 principles:
• Differential Optical Absorption Spectroscopy (DOAS)
• Fourier Transform Infrared (FTIR)
• Non-Dispersive Infrared (NDIR)
• Tunable Laser Diode Absorption Spectroscopy (TLDAS)

16.

Air quality monitoring
Measurement of nitric oxides (NOx) by chemiluminescence
Chemiluminescent reaction
NO + O3 ==> NO2+ O2 + hv (0.6 – 3 μm)

17.

Air quality monitoring
Measurement of sulphur dioxide (SO2) by UV fluorescence

18.

Air quality monitoring
Measurement of suspended particles (particulate matter – PM)
Fraction
Size range
PM10
(thoracic fraction)
≤ 10 μm
PM2.5
(respirable fraction)
≤ 2.5 μm
PM2.5 – PM10
(coarse fraction)
2.5 - 10 μm
PM1
(fine fraction)
≤ 1 μm
Ultrafine (UFP or UP)
≤ 0.1 μm
Aerosol = particles + gas

19.

Air quality monitoring
Measurement of suspended particles (particulate matter – PM)
Beta Attenuation Method