Particulate Matter (PM)
Standards in Asia
A micron (or
micrometer) is a millionth of a meter. To give you an idea of how
small PM 10 is, the dot above the letter "i" in a typical newspaper
measures about 400 microns!
2000 particles of PM2.5
could fit end-to-end across one end of a paper clip!
Figure 1. The size of various particles in comparison to the
width of a human hair.
PM 10 particles are small enough to
be inhaled and accumulate in the respiratory system. In the last decade, health
studies indicated that particles even smaller than PM 10 can cause even more
health problems! Now, in addition to monitoring PM 10, scientists and
technicians monitor fine particles called PM 2.5, these particles measure 2.5
microns in diameter or smaller, or about 1/10,000 of an inch. These tiny
particles are about 30 times smaller than the width of a hair on your head!
These tiny particles are small enough to get inhaled past our defensive nose
hairs and into our lungs. But it doesn't stop there! PM 2.5 can pass from our
lungs into our blood supply and be carried throughout our bodies.
To protect us from the harm of air
pollutants, the U.S. Environmental Protection Agency (USEPA) established National Ambient
Air Quality Standards (NAAQS) for
criteria air pollutants that are thought to cause the most harm to the health
of humans and the environment. Particulate matter is one of these criteria pollutants.
There are two PM 10 standards, a 24-hour standard and an annual
standard. These standards are:
- 150 micrograms per cubic meter (ug/m3) for the 24 hour standard
- 50 micrograms per cubic meter (ug/m3) for the annual standard
To determine if an area meets the
annual standard, data is collected daily and averaged over the entire year. The
last three years of annual averages are used to determine attainment. An
area will meet the 24-hour standard if the number of days per calendar year
above 150 ug/m3 is equal to or less than "1."
In 1997, the USEPA revised their PM
standard to take into account new findings about significant health problems
associated with fine particulates, PM 2.5 and smaller. To the old PM10
standards, the USEPA added two new PM 2.5 standards set
at:
- 65 micrograms per cubic meter (ug/m3)as the 24 hour standard
- 15 micrograms per cubic meter (ug/m3)as the annual standard
Ref:
http://www.hcdoes.org/airquality/monitoring/pm.htm
PM
Standards in Asia
Of the 19
countries and one city surveyed in 2009 and 2010, CAI-Asia found that four
countries (Afghanistan, Cambodia, Lao PDR and Myanmar) still has to establish
air quality standards.
While most Asian countries have adopted the
PM10 standard in differing degrees, more is needed in the development of a
PM2.5 standard. Several Asian countries’ have more lenient PM10 and PM2.5
standards when compared with European Union Air Quality Standards (EU AQS),
World Health Organization (WHO) Air Quality Guidelines, and United States
Environmental Protection Agency (USEPA) National Ambient Air Quality Standards
(NAAQS).
Table 1. Categories of PM
according to size
|
|
Type
|
Size
|
TSP
|
Particles with
aerodynamic diameter between 20-50 micrometers
|
PM10
|
Particles with
aerodynamic diameters less than 10 micrometers which may reach the upper part
of the airways and lung.
|
PM2.5
|
Particles with
aerodynamic diameters 2.5 micrometers and smaller regarded as more dangerous
because they penetrate more deeply into the lungs and may reach the alveolar
region
|
Ultrafines
|
Particles with
aerodynamic diameters 0.1 micrometers and smaller
|
Air Quality Index (AQI) - A Guide to Air Quality and Your Health
The
AQI is an index for reporting daily air quality. It
tells you how clean or polluted your air is, and what associated health effects
might be a concern for you. The AQI focuses on health effects, you may
experience within a few hours or days after breathing polluted air. EPA
calculates the AQI for five major air pollutants regulated by the Clean Air
Act: ground-level ozone, particle pollution (also known as particulate matter),
carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these
pollutants, EPA has established national air quality standards to protect
public health .Ground-level ozone and airborne particles are the two pollutants
that pose the greatest threat to human health in this country.
How Does the AQI Work?
Think
of the AQI as a yardstick that runs from 0 to 500. The
higher the AQI value, the greater the level of air pollution and the
greater the health concern. For example, an AQI value of 50 represents good air
quality with little potential to affect public health, while an AQI value over
300 represents hazardous air quality.
An
AQI value of 100 generally corresponds to the national
air quality standard for the pollutant, which is the level EPA has set to
protect public health. AQI values below 100 are generally thought of as
satisfactory. When AQI values are above 100, air quality is considered to be
unhealthy-at first for certain sensitive groups of people, then for everyone as
AQI values get higher.
Understanding the AQI
The purpose of the AQI is to help you understand what local air quality means to your health. To make it easier to understand, the AQI is divided into six categories:
References
Clean Air Initiative for Asian
Cities (CAI-Asia) Center, 2010. Air Quality in Asia: Status and Trends – 2010
US
EPA. 2010. Particulate Matter.
http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html
Philippines:
Air Quality Profile - 2010 Edition
Ambient
Air Quality Guideline Values
The National
Ambient Air Quality Guideline Values (NAAQGV) set forth in the CAA
(Clean Air Act) comprise of PM10, total suspended particulates (TSP), Sulfur
dioxide (SO2), Nitrogen dioxide (NO2), Carbon monoxide (CO), ozone (O3),and
lead (Pb).
Compared with the World Health Organization (WHO) Guidelines, the
NAAQGV for PM10 (24-hour and annual) and SO2 (24-hour) are more lenient (Table
3.1.2). On the other hand, the 8-hour NAAQGV for O3 is relatively more
stringent than the WHO Guideline whilst the CO and Pb NAAQGVs are generally
comparable with the WHO Guidelines. There are currently no plans to revise the
standards.
Table 3.1.2. NAAQGV vs. WHO Guidelines
(μg/m3)
Pollutant
|
Average
Time
|
NAAQGV
(National
Ambient Air Quality Guideline Values)
|
WHO
(World
Health Org)
Guidelines
|
PM10
|
24-hour
|
150
|
50a
|
Annual
|
60
|
20a
|
|
TSP
|
24-hour
|
230
|
-
|
Annual
|
90
|
-
|
|
NO2
|
1 hour
|
-
|
200a
|
24-hour
|
150
|
-
|
|
Annual
|
-
|
40a
|
|
SO2
|
10 min
|
-
|
500a
|
1 hour
|
-
|
-
|
|
24 hour
|
180
|
20a
|
|
Annual
|
80
|
-
|
|
O3
|
1-hour
|
140
|
-
|
8-hour
|
60
|
100a
|
|
24-
hour
|
-
|
-
|
|
CO
|
1-hour
|
35,000
|
30,000a
|
8-hour
|
10,000
|
10,000a
|
|
Pb
|
3 month
|
1.5
|
|
Annual
|
1.0
|
0.5a
|
Guidelines refer to the safe
level of a pollutant, for a given average time, to
protect the public from acute
health effects. μg/m3=micrograms per cubic meter
Other Standards:
Air
Pollutant
|
National Ambient Air Quality Standard
|
National Ambient Air Quality Standard
|
Ozone
|
100 ug/m3 for 3-8 hour mean
|
|
Nitrogen Oxide
|
40 ug/m3 for
annual mean
|
200 ug/m3 for annual mean
|
Sulfur Dioxide
|
20 ug/m3 for
24 hour mean
|
500 ug/m3 for
10 minute mean
|
Source:
WHO.
2000. Guidelines for Air Quality. http://whqlibdoc.who.int/hq/2000/WHO_SDE_OEH_00.02_pp1-104.pdf
; WHO. 2006. WHO Air Quality
Guidelines for
particulate matter, ozone, nitrogen dioxide and sulfur dioxide. Global Update
2005. Summary of Risk Assessment.
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