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Topic
PM and its components, origin and Health Hazard

What is PM, and how does it get into the air?
PM stands for particulate matter (also called particle pollution): the term for a mixture of solid
particles and liquid droplets found in the air
...
Others are so small they can only be
detected using an electron microscope
...
PM has no fixed composition
...
g
...
US EPA described PM pollution as ‘mixture of
mixtures’
...

Types of PM particles
Primary particles
Directly emitted from sources
Secondary particles
Form as a result of the interaction of chemicals such as SO2, NOx and VOCs with other
compounds in the air
...
5 microns
...
PM10
• Bypass the body’s natural defenses in the nose and throat and enter lungs
...
5

Fine particles, particle diameter 2
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• Remains suspended in the air and can travel extremely long distances
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PM 2
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PM0
...
1 micron diameter
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• Pass from lung tissue into blood stream
...
1
• Circulate like oxygen molecules
...

Mass and composition in urban environments tend to be divided into two principal groups:
coarse particles and fine particles
...
5 µm
...
5 µm in aerodynamic diameter (PM2
...
The smaller particles contain the secondarily formed aerosols (gas-to-particle
conversion), combustion particles and recondensed organic and metal vapours
...
The
fine fraction contains most of the acidity (hydrogen ion) and mutagenic activity of particulate
matter, although in fog some coarse acid droplets are also present
...
5 µm), the largest number of particles
is found in the very small sizes, less than 100 nm
...

Particulate air pollution is a mixture of solid, liquid or solid and liquid particles suspended in the
air
...
It is convenient to classify
particles by their aerodynamic properties because: (a) these properties govern the transport and
removal of particles from the air; (b) they also govern their deposition within the respiratory
system and (c) they are associated with the chemical composition and sources of particles
...
Particles are sampled and described on
the basis of their aerodynamic diameter, usually called simply the particle size
...
The largest particles, called the coarse fraction (or
mode), are mechanically produced by the break-up of larger solid particles
...
Traffic produces road dust and air turbulence that can stir up road dust
...
Pollen grains, mould spores, and plant and
insect parts are all in this larger size range
...
Smaller particles, called
the fine fraction or mode, are largely formed from gases
...
1 µm,
are formed by nucleation, that is, condensation of low-vapour-pressure substances formed by
high-temperature vaporization or by chemical reactions in the atmosphere to form new particles
(nuclei)
...
Particles in this nucleation range or mode grow by coagulation, that is, the
combination of two or more particles to form a larger particle, or by condensation, that is,
condensation of gas or vapour molecules on the surface of existing particles
...

Therefore the efficiency of both coagulation and condensation decreases as particle size
increases, which effectively produces an upper limit such that particles do not grow by these
processes beyond approximately 1 µm
...
1 and 1
µm, the so-called accumulation range
...
They can also be
produced by condensation of gases that have been converted in atmospheric reactions to lowvapour-pressure substances
...
Nitrogen
dioxide (NO2) is oxidized to nitric acid (HNO3), which in turn can react with ammonia (NH3) to
form ammonium nitrate (NH4NO3)
...
Secondary sulphate and nitrate particles
are usually the dominant component of fine particles
...
e
...


Components
Particle pollution includes:

PM10 : inhalable particles, with diameters that are generally 10 micrometers and smaller; and
PM2
...
5 micrometers and smaller
...
5 micrometers? Think about a single hair from your head
...

Recently a comprehensive report on PM phenomology in Europe was compiled (7)
...
5 mass
concentrations, except at kerbside sites where mineral dust (including trace elements) is also a
main contributor to PM10
...
5
...
5 and somewhat less
to PM10 at all sites, including the natural background sites
...
Because of its complexity and the importance of particle size in
determining exposure and human dose, numerous terms are used to describe particulate matter
...
g
...
Others refer more to the site
of deposition in the respiratory tract, e
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“inhalable particles”, which pass into the upper airways
(nose and mouth), and “thoracic particles”, which deposit within the lower respiratory tract, and
“respirable particles”, which penetrate to the gas-exchange region of the lungs
...


Sources of PM
Components of particulate matter (PM) include finely divided solids or liquids such as dust, fly
ash, soot, smoke, aerosols, fumes, mists and condensing vapors that can be suspended in the air
for extended periods of time
...

Natural sources – forest fires, volcanoes, PM
These particles come in many sizes and shapes and can be made up of hundreds of different
chemicals
...

Most particles form in the atmosphere as a result of complex reactions of chemicals such as
sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries
and automobiles
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• Inflammation of lung tissue
...

• Development of chronic lung disease
...

• Pre-term birth and low birth weight
...

People at risk (sensitive human population )
1
...

2
...

3
...

4
...

5
...
The reduction in life expectancy is primarily due to increased cardio-pulmonary and
lung cancer mortality
...

Rationale:
Given the absence of clearly documented thresholds in the exposure-response relationships for
long-term as well as short-term effects (see answer and rationale to question 3), and given the
fact that these exposure response relationships have been established in studies at currently
observed exposure ranges, adverse effects on health occur with certainty in Europe
...
Recently it was shown that a part of effects of air
pollution on life expectancy can also be calculated using time series studies (76)
...

A recent estimate for Austria, France and Switzerland (combined population of about 75 million)
is that some 40 000 deaths per year can be attributed to ambient PM (80)
...
The Global Burden of Disease project has recently
expanded its analysis of the impact of common risk factors on health to include environmental
factors
...

Strong evidence on the effect of long-term exposure to PM on cardiovascular and
cardiopulmonary mortality comes from cohort studies (see also rationale to question 1)
...
In the cities where also
PM2
...
The
re- analysis by HEI (10) essentially found the same results
...
(13) the
ACS cohort was extended, the follow-up time was doubled to 16 years and the number of deaths
was tripled
...
For all causes and cardiopulmonary
deaths, statistically significant increased relative risks were found for PM2
...
TSP and coarse
particles (PM15 – PM2
...
The US-Harvard Six
Cities Study (82) examined various gaseous and PM indices (TSP, PM2
...
Sulfate and PM2
...
The re-analysis of HEI (10) also essentially confirmed these results
...
The
association between exposure to air pollution and (cause specific) mortality was assessed with
adjustment for potential confounders
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95, 95% CI 1
...
52) and, less consistently, with the estimated
ambient background concentration (1
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68–2
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The relative risk for living near a major
road was 1
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94–2
...
Non-cardiopulmonary, non-lung cancer deaths were
unrelated to air pollution (1
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54–1
...
The authors conclude
that long-term exposure to traffic-related air pollution may shorten life expectancy
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5 and lung cancer (82)
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5 and increased risk of dying of lung cancer (13)
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A few animal studies using long-term exposure to diluted diesel motor exhaust (DME) have been
reported
...
High particle deposition-

related inflammatory effects, including generation of high concentration of oxygen radicals and
increased oxidative DNA damage in proliferating epithelial lung cells, may be the mechanism by
which particles induce lung tumours in rats (83, 84)
...
No inflammatory or other toxic effects
were found in rats chronically exposed to lower concentrations of DME (87)
...

Thus, this kind of particle-induced inflammation, together with the carcinogenic potential of
diesel soot-attached PAH, may add to the air pollutant-related lung cancer in humans
...
However,
in high-exposure animal test systems, diesel particulate matter has been shown to be the most
important fraction of diesel exhaust (84)
...
McConnell et al
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However, the high
correlation of PM10, acid, and NO2 precludes clear attribution of the results of this study
specifically to PM alone
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(89, 90, 91) performed three consecutive
surveys on children from former East Germany
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Krämer et al
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A
decrease of bronchitis was seen between beginning and end of the study, being most strongly
associated with TSP
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(79) investigated the effect of long-term exposure
to air pollution in a cross-sectional study on children from 10 Swiss communities
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Collinearity of PM10, NO2, SO2 and O3 prevented any causal separation
of pollutants
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(93) and Zemp et al
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They found that chronic cough and chronic phlegm and
breathlessness were associated with TPS, PM10 and NO2, and that lung function (FEV1, FVC)
was significantly reduced for elevated concentrations of PM10, NO2 and SO2
...
(95) reported an association between both BS and SO2 levels in various areas
of Krakow, Poland, and slowed lung function growth (FVC and FEV1)
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Follow-up lung
function tests were administered to children who had moved away from the study area
...

In addition to aggravation of existing allergy, particulates have been shown in some experimental
systems to facilitate or catalyse an induction of an allergic immune response to common

allergens (96)
...


Independent adverse effects of PM
Ambient PM per se is considered responsible for the health effects seen in the large multi-city
epidemiological studies relating ambient PM to mortality and morbidity such as NMMAPS and
APHEA
...
That ambient PM is responsible per se
for effects on health is substantiated by controlled human exposure studies, and to some extent
by experimental findings in animals
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The
sometimes high correlation between PM and some gaseous components of ambient air pollution
makes it difficult to statistically separate their effects on health
...
Mutual adjustment has been shown even to increase effects of PM as well as ozone in
some areas (51)
...

The multi-city time series study NMMAPS has found PM effects to be insensitive to adjustment
for a number of gaseous pollutants
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5 alone is not sufficient to represent fully the impact of complex air pollution
mixtures on mortality (see also NO2 document)
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Such changes in effect estimates show that SO2 per se is not
responsible, but co-varies with other components that are
...
To what extent
SO2 is a surrogate for small-area spatial variations of air pollution components (including PM)
not captured by single city background monitoring sites remains unclear in the ACS study
...
NO2 co-varies with PM in all areas
where traffic is a major source of PM
...
It should be noted that when areas with high and low traffic contributions to ambient PM
are included in time series studies (as in APHEA), the correlation between ambient PM and NO2

becomes less, and the two can be analysed jointly
...
It was shown that
ambient PM predicted personal PM concentrations well on a group level however, ambient
gaseous air pollution concentrations were not correlated with personal gaseous air pollution
concentrations, which were also found to be much lower than ambient concentrations,
presumably due to incomplete penetration of gases to indoor spaces, and reactions of gases with
indoor surfaces
...
5 (positive
in summer, negative in winter), ambient NO2 predicted personal PM2
...
5 in winter, and ambient SO2 was negatively
associated with personal PM2
...
These results suggest that ambient gaseous pollution
concentrations are better surrogates for personal PM of outdoor origin than for personal exposure
to the gaseous components themselves
...
Indeed, it has been very difficult to show
convincingly that certain PM attributes (other than size) are more important determinants of ill
health than others
...

The controlled human exposure data show a direct effect of PM on the induction of inflammation
in humans at concentrations that are somewhat higher than generally encountered in ambient air
(see question 1)
...
Studies with experimental animals also to
some extent support the epidemiological data (113, 129)
...
This is an
interesting observation that may account for findings in epidemiological studies showing
associations between coarse PM exposure and health effects
...
Gamble and
Nicolich have argued that the PM doses required to elicit adverse effects in humans by active
smoking and various occupational exposures are orders of magnitude higher than doses obtained
from ambient PM exposures (131)
...


How Can I Reduce My Exposure to PM?
You can use air quality alerts to protect yourself and others when PM reaches harmful levels:
AirNow: Every day the Air Quality Index (AQI) tells you how clean or polluted your outdoor air
is, along with associated health effects that may be of concern
...


Go to About AirNow to learn how you can get AQI notifications
...


Summary
Particulate matter (PM) is a complex mixture of air borne particles that differ in size, origin and
chemical composition, all of which are <10 µm in size
...
g
...
PM is one of the six EPA ‘criteria pollutants’
...
The
particles may consist either of only one chemical (e
...
sulphate, sulphuric acid, or lead oxide )
OR a number of pollutants ( organic chemicals, metals, dust )
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• PM is among the most harmful of all air pollutants
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PM composed of
liquid aerosol particles and solid aerosol particles –suspended in and move with the air
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• Generally below 5 µm size
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Sources of PM and PM
precursors• Mobile sources – Vehicles – VOCs , NO2, PM• Stationary sources – power plants,
factories – NO2, SO2, PM• Area sources – dry cleaners, gas stations – VOCs
...
Particle sizes PM10 PM 2
...
1 Ultra-fine particles Fine
particlesCoarse particles
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Characteristics of particles • Inhalable
coarse particles, Diameter range 10 -2
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• Undergo rapid sedimentation • Occur near
roadways and dusty industries
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• Fine particles, particle diameter 2
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• Remains suspended in the air
and can travel extremely long distances
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PM 2
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• Ultra-fine
particles, nano-particulates, smaller than 0
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• Consist primarily of inorganic
ions, hydrocarbons and metals
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PM 0
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Suspended particulate matter (SPM) • About 100 microns in diameter Dust •
Removed in the nasal passages • e
...
coal dust, cement dustFumes • Suspended solids, in diameter
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0 microns • e
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Sulphuric
acid mist smoke • Solid particles, 0
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0 microns • Incomplete combustion of fossil
fuelsAerosol • Liquid or solid aerosols, <1
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Major features of particles • Inhalable
particles PM10 • Deposit in the extra thoracic /upper tracheo-branchial region PM 2
...
1 • Ultra-fine particles • Pass into the circulatory system
Sources of particle pollution• Motor vehicle emissions• Power generation• Industrial
combustion• Metal smelting• Wood / biomass burning• Construction / demolition• Road
dust
...


Particle deposition in the lungs Coarse • Deposit in the upper respiratory tract and large airways
(nose and throat) and areparticles cleared out
...
particles • Stay there longer periods of time
...
particles Particle size is the most important factor for
target tissue deposition
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• Inflammation of lung tissue
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• Development of chronic lung disease
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•
Pre-term birth and low birth weight
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People at risk (sensitive human population )1
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2
...
3
...
4
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5
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Environmental impact• Impairment of
visibility- fine particles reduce visibility
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They make lakes and streams acidic,
deplete nutrients in soil and damage sensitive forests and farm crops
...
Health effects
of long-term exposure to anthropogenic particulates• Asthma• Bronchitis• Chronic obstructive
pulmonary disease (COPD)
...
•
Lung cancer

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Title: PM, its Components, Origin and Health Hazards
Description: These notes describe PM( Particle Pollution). Types and Characteristics of PM. Formation and Size of PM. Sources of PM. Detail Effects of PM. How to minimize its effects.

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