Groundwater System

Check out this link: http://earthguide.ucsd.edu/earthguide/diagrams/groundwater/index.html =))

 Particulate Matter (PM) Standards in Asia

 PM 10 & PM 2.5

 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.

http://whqlibdoc.who.int/hq/2006/WHO_SDE_PHE_OEH_06.02_eng.pdf

Phosphorus Cycle

A SOIL-BASED VIEW OF THE PHOSPHORUS CYCLE
Initially, phosphate weathers from rocks. The small losses in a terrestrial system caused by leaching through the action of rain are balanced in the gains from weathering rocks. In soil, phosphate is absorbed on clay surfaces and onganic matter particles and becomes incorporated (immobilized). Plants dissolve ionized forms of phosphate. Herbivores obtain phosphorus by eating plants, and carnivores by eating herbivores. Herbivores and carnivores excrete phosphorus as a waste product in urine and feces. Phosphorus is released back to the soil when plants or animal matter decomposes and the cycle repeats.





A GLOBAL VIEW OF THE PHOSPHORUS CYCLE
The phosphorus cycle occurs when phosphorus moves from land to sediments in the seas and then back to land again. The main storage for phosphorus is in the earths crust. On land phosphorus is usually found in the form of phosphates. By the process of weathering and erosion phosphates enter rivers and streams that transport them to the ocean. Once in the ocean the phosphorus accumulates on continental shelves in the form of insoluble deposits. After millions of years, the crustal plates rise from the sea floor and expose the phosphates on land. After more time, weathering will release them from rock and the cycle's geochemical phase begins again.






AN ECOSYSTEM VIEW OF THE PHOSPHORUS CYCLE
The ecosystem phase of the phosphorus cycle moves faster than the sediment phase. All organisms require phosphorus for synthesizing phospholopids, NADPH, ATP, nucleic acids, and other compounds. Plants absorb phosphorus very quickly, and then herbivores get phosphorus by eat plants. Then carnivours get phosphorus by eating herbivores. Eventully both of these organisms will excrete phosphorus as a waste. This decomposition will release phosphorus into the soil. Plants absorb the phosphorus from the soil and they recycle it within the ecosystem.

Nitrogen Cycle

QUESTIONS:

1. The atmosphere is 80% nitrogen: why do you think plants and animals can't use 

    nitrogen as it is found in the atmosphere?

2. Explain what is meant by nitrogen fixation.

3. What is the role of bacteria in the nitrogen cycle?

4. Why don't legumes need nitrogen-containing fertilizers?

5. Why is nitrogen so important for living things?

6. What are the processes involved in the nitrogen cycle?

ANSWERS:

1. Plants and animals cannot use nitogen as it is found in the atmosphere as the nitrogen is in a form not usable to organisms. Plants and animals do not have the enzymes to 'fix' the nitrogen.

2. Nitrogen fixation is a process by which nitrogen (N₂) in the atmosphere is converted into ammonia (NH₃).^[1] Atmospheric nitrogen or elemental nitrogen (N₂) is relatively inert: it does not easily react with other chemicals to form new compounds. Fixation processes free up the nitrogen atoms from their diatomic form (N₂) to be used in other ways.

3. Bacteria actually uses and transforms the nitrogen into nitrogen that can again be used .

4. Legumes "fix" nitrogen in nodules on their roots, so they do not need additional nitrogen-containing fertilizers.

5. Nitrogen is a major component of chlorophyll, which is used by plants in the process of photosynthesis to produce sugars, water and carbon dioxide. 

It is also an essential component of amino acids which make up proteins. Some proteins act as structural units in the plant while others act as enzymes, catalysing biological reactions.

Nitrogen is also a component of ATP, which provides energy for reactions such as respiration.

Finally, nitrogen is a significant component of DNA, the genetic material which allows cells to grow and replicate.

6. Step 1: Nitrogen-fixation 
Atmospheric: Happens when Nitrogen (N2) is oxidized at high temperatures (by lightning, in internal combustion engines) to make nitrite (NO2). This can combine with water to form nitric acid (H2NO3), which is deposited on earth through rainfall. 
Biological: Done by bacteria which can convert N2 into ammonia (NH3) if an energy source is present. Some get this energy by directly absorbing sunlight (blue-green algae) or by living in the roots of plants (legumes, alder trees), who provide them with food (Rhizobium, Azospirillium). 
Step 2: Conversion to Ammonia. As amino acids and nucleic acids require N in the form of Ammonia, if nitrate (NO3) present, it must be converted to NH3. This is done through Nitrate reductase enzymes. 
Step 3: Biological Use. Ammonia is incorporated into proteins, nucleic acids 
Step 4: When organism dies, ammonia is relased back into the biosphere through the process of Ammonification, in which water is added to proteins to make carbon dioxide and ammonia. This process happens during digestion, and is also done by bacterial and fungal decomposers. 
Step 5: If ammonia released into oxygen rich (anerobic) soil, other bacteria can convert it into nitrite or nitrate through the process of Nitrification:

NH4+ + 2O2 = NO3- + H2O + 2H.

This is a problem, as it gives the molecule which contains Nitrogen a negative charge, which repels it from soil particles, causing it to be easily leached into streams and groundwater. 
Step 6: If soils remain anerobic, another group of poop will convert it back into inert, atmospheric N2 through the process of Denitrification. In this process, bacteria use nitrate as an Oxygen source for respiration: C6H12O6 + 4NO3- = 6CO2 + 6H2O + 2N2.