PARTICULATE MATTER
It is a mixture of solid particles and liquid droplets suspended in the air e
formed in the atmosphere by transformation of gaseous emissions. It
describes a wide variety of airborne material. PM pollution consists of
materials (including dust, smoke, and soot), that are directly emitted into the
air or result from the transformation of gaseous pollutants. Particles come
from natural sources (e.g., volcanic eruptions) and human activities such as
burning fossil fuels, incinerating wastes, and smelting metals It is in form of
coarse (PM10) and fine particles(PM2.5).
PM
10
They are the coarse particles with aerodynamic diameter between 2.5µ
m and 10µ m. They are formed by mechanical disruption like crushing,
grinding, abrasion of surfaces; evaporation of sprays, and suspension of
dust having composition of aluminosilicate and other oxides of crustal
elements. major sources including fugitive dust from roads, industry,
agriculture, construction and demolition, and fly ash from fossil fuel
combustion.
PM2.5
They are fine particles with aerodynamic diameter less than 2.5µ m
The major sources of PM2.5 are fossil fuel combustion, vegetation
burning, and the smelting and processing of metals. they are composed
of various combinations of sulfate compounds,nitrate compounds,
carbon compounds, ammonium, hydrogen ion, organic compounds,
metals (Pb,Cd, V, Ni, Cu, Zn, Mn, and Fe), and particle bound water. In
addition, fine particles are associated with decreased visibility ( haze)
impairment in many cities of the U.S
FINE PARTICLES
COARSE PARTICLES
FORMATION
Gases
Large solids/droplets
COMPOSITION
Sulfate (SO42 ¯); Nitrate
(NO¯3);ammonium (NH4+ );
hydrogen ion(H+ ); elemental
carbon; organic compounds
metals (Pb, Cd, V, Ni, Cu, Zn,
Mn,Fe).
Resuspended dust (e.g. soil
dust,street dust); coal and oil fly
ash;metal oxides of crustal
elements(Si, Al, Ti, Fe); CaCO3,
NaCl, sea salt; pollen, mould
spores;plant/animal fragments.
SOLUBILITY
Largely soluble, Hygroscopic
and deliquescent
Largely insoluble and
non-hygroscopic
SOURCES
Combustion of coal, oil,
gasoline, diesel, wood,
atmospheric transformation
products of NOx ,SO2 and
organic compounds like
biogenic species, smelters,
steel mills, etc.
Resuspension of industrial dust
and soil tracked onto roads;
suspension from disturbed soil
(e.g. farming, mining); biological
sources; construction and
demolition; coal and oil
combustion; ocean spray
TRAVEL DISTANCE
100s to 1000s of kilometers
<1 to 10s of kilometers
LIFESPAN
Days to Weeks
Minutes to hours
WHAT WE BREATH IMPACT OUR
HEALTH
Pure Air--nitrogen (78%),Oxygen (21%), Argon, CO2. . .
+
 Various gaseous pollutants including: SO2, NO2, CO, O3 . .
+

Particulate matter – Course particles (> 2.5 mm in diameter)
– Fine particles (< 2.5 mm in diameter)
+
 Other air toxics
PARTICLE ORIGIN
Primary: emitted directly from source as particles
Unburned carbon particles from high energy combustion,
e.g., autos, wood burning, power generation
Secondary: precursor gases or added to existing particles
SO2 → sulfuric acid + ammonia = sulfate particles
coal-fired power plants, fertilizer
NO2 → nitric acid + ammonia = nitrate particles
coal-fired power plants, biologicals, autos, fertilizer
Existing particles + VOCs = organic “carbon” particles
autos, vegetation
Sources of PM and PM Precursors
Mobile Sources
(vehicles)
VOCs, NO2, PM
Area Sources
(drycleaners, gas stations)
VOCs
Stationary Sources
(power plants, factories)
NO2, SO2, PM
Natural Sources
(forest fires, volcanoes)
PM
Some Famous Air Pollution Episodes
 1948 Donora Smog Disaster, 20 excess deaths, over
7,000 sick
 1952 London Fog estimated 12,000 excess deaths
 1966 New York City 80 excess deaths
Air Pollution, Geography and Meteorology (inversions) all
contributed
SIZE
REGULATIONS OF PM
PM is one of the six EPA “criteria pollutants” that have
been determined to be harmful to public health and the
environment. (The other five are ozone, sulfur dioxide,
nitrogen dioxide, carbon monoxide, and lead.)
EPA is required under the Clean Air Act to set
national ambient air quality standards (NAAQS) to
protect public health from exposure to these pollutants.
Areas that exceed the NAAQS are designated as
nonattainment, and must institute air pollution control
programs to reduce air pollution to levels that meet the
NAAQS.
AERODYNAMIC DIAMETER
Establishing a particle size definition for irregularly shaped particles necessitates the
use of a standardized measure referred to as the aerodynamic diameter, measured in
microns or micrometers (μm), a unit equal to one millionth of a meter. The graph at
the right shows the distribution of the 4 main particle size categories, with the
categories historically and currently regulated by EPA indicated below. By comparison,
a human hair is approximately 70 microns in diameter.
HEALTH EFFECTS
Overwhelming body evidence from toxicological,
epidemiological & clinical work support associations between
exposure to PM and a broad range of adverse health effects.
Health effects diverse in
scope
severity
duration
clinical significance
Exacerbation of heart and lung disease; pre-mature death;
cancer
HEALTH EFFECTS
SHORT TERM EFFECTS
Mortality from cardiopulmonary diseases
hospitalization and emergency department visits for
cardiopulmonary diseases
increased respiratory symptoms
decreased lung function
physiological changes or biomarkers for cardiac
changes.
SOURCES
AIRBORNE PARTICULATE SIZE CHART
MOBILE SOURCES OF PM2.5
Acute exposures (min-hrs)
Very short-term transient PM2.5 elevations of concern.
Associations between 1-12 hr exposures and acute
cardiovascular and respiratory events, including
myocardial infarction in older adults and asthma
symptoms in children
e.g., Adamkiewicz et al. 2004; Delfino et al. 1998, 2002; Gold et al. 2000;
Henneberger et al. 2005; Mar et al. 2005; Morgan et al. 1998; Peters et
al. 2001.
EXAMPLES OF EFFECTS
Other health indicators
Out-of-hospital trips to physicians
Lost-work/school days or productivity
Over-the-counter drug consumption
Zmirou et al. 1999 found this was the largest cost from exposure to air
pollution.
Total annual effects of PM2.5 in Ontario:
1,725 premature deaths from both respiratory and cardiac causes
1,087 hospital admissions
48,000 visits to emergency departments
567,000 asthma-symptom days
8.35 million restricted-activity days.
(MOE 1999, Abelsohn et al. 2002).
INCREASING CARDIOVASCULAR EFFECT
Until the mid 1990s,
most research focused
on the association of
PM exposure with
respiratory disease.
Since then, there has
been growing evidence
of cardiovascular
health effects from
PM.