Buildings - LEED Certification

What is LEED?

LEED (Leadership in Energy and Environmental Design)  is a  market­-driven program that provides third-party verification of green buildings.  LEED works with all types of buildings and  addresses their full lifecycle.

Participation in the  LEED process demonstrates leadership and social responsibility. LEED ensures  building owners  healthy indoor spaces. LEED projects have been successfully established in 135 countries.

The Process

Commercial buildings need to fulfill all LEED prerequisites and earn a minimum of 40 points on a 110-point LEED rating system scale. Residential buildings require a minimum of 45 points on a 136-point scale

LEED-certified buildings are designed to:

•  Increase asset value and Lower operating costs
• Reduce waste sent to landfills
• Conserve energy and water
• Be healthier and safer for occupants
• Reduce harmful greenhouse gas emissions
• Qualify for tax rebates, zoning allowances and other incentives in hundreds of cities.

LEED benefits businesses

Green building benefits the environment and our health. It promises a better future.

How businesses are benefited by LEED Certification

1. It provides competitive edge in today's market.

Green buildings attract buyers and tenants because they provide lower operating costs and healthier indoor environments. Study shows that when developers choose to go for new green construction, occupancy increases 6.4 % and rent 6.1 %. For existing buildings undergoing green updates, occupancy increases 2.5 % and rent increases 1 %. Property owners discovered the cost benefit chart which shown below:

	Operating costs	Building value	ROI	Occupancy	Rent
New construction	drop 13.6%	rises 10.9%	improves 9.9%	rises 6.4%	rises 6.1%
Existing building projects	drop 8.5%	rises 6.8%	improves 2.5%	rises 1%	rises 19.2%

2. It lowers the risk.

LEED certification results in faster sale and renting of building then the normal building in the same visinity. Hence, it reduces the financial risk for owners. It reduces the consumption of energy by using renewable resources of energy and better air and water quality are beneficial to health. It also runs the building with minimum wastage of water and electricity.

3. Tenants are attracted by LEED certified Buildings.

4. It’s cost effective.

Green building pays. LEED can help it pay even more. Green Building results in total saving of 20% in total construction cost. Even while renting or selling LEED certified buildings per square foot goes higher than a normal building.

Source: usgbc © 2013 U.S. Green Building Council

Roof Top System- Its Components

A Solar System generally  comprises of the following elements: Solar Panel, a Charge Controller, a Power Inverter, a Monitor and Electrical Distribution System. As seen with each other technologies each component has different manufacturers , quality, features and price.

Solar Panel: A Solar Panel consists of silicon crystals which converts the rays on the sun into electricity. They supply electricity, required for charging batteries and running the appliances either directly or through power inverter. A combination of panels is used to produce the electricity which is  more than the  required and excess of energy is stored in battery for nighttime or cloudy days. They are available in different sizes, voltages and amperages. They can be connected be in series, parallel or both depending on design requirements of the system.

Charge Controller: It is a vital component and functions like the brain of system. It monitors the electricity produced by solar panels and then regulates the electricity to charge the batteries and prevent them from over-charging. It helps to increase battery life and performance. Different technologies are available for selection including Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT) charge controllers.

Batteries: They are required to store excess power generated from solar panels for later use. Without battery, power would only be available when the sun is shinning. The batteries are available in different voltages and varying amp-hour ratings depending on system requirements.

Inverter: It converts the DC Volts produced by solar panels into AC volts. The inverters can be used to charge batteries by connecting it to the backup generator or an AC electrical source. It is important to choose the right inverter for the demand and power requirements of the system so that the components can function properly.

Monitor: It is used to monitor the condition of the battery, the power generated by solar panels and consumption of power by the users. The monitors available in the market will provide you with information for protection of batteries, help’s to locate the source of the system  problems where they occur and allows to reduce generator use , by knowing when to shut it down.

Generator: Gas powered generator is a good investment to keep the batteries charged during extended period of rainy/cloudy days. It can also provide temporary power when there is high demand for power. It is a handy tool to have when sunlight is not available.

On Grid: When to system is connected to local utility.

Off Grid: It is a system where solar powered structure would not be connected to external electrical device.

Grid Tie: It means that you can use solar energy when it is available and when that source is not available, have the system automatically switch to on-grid electricity from the power company.

Function of the PV inverter

The tasks of a PV inverter are as varied as they are demanding:

1. Low-loss conversion
One of the most important characteristics of an inverter is its conversion efficiency. This value indicates what proportion of the energy “inserted” as direct current comes back out in the form of alternating current. Modern devices can operated with an efficiency of around 98 percent.

2. Power optimization
The power characteristics curve of a PV module is strongly dependent on the radiation intensity and the temperature of the module – in other words, on values that continually change over the course of the day. For this reason, the inverter must find and continually observe the optimal operating point on the power characteristics curve, in order to “bring out” maximum power from the PV modules in every situation. The optimal operating point is called the "maximum power point" (MPP), and the search for, and tracking of, this MPP is correspondingly called "MPP tracking." MPP tracking is extremely important for the energy output of a PV plant.

3. Monitoring and securing
On the one hand, the inverter monitors the energy yield of the PV plant and signals any problems. On the other, it also monitors the power grid that it is connected to. Thus, in the event of a problem in the power grid, it must immediately disconnect the plant from the grid for reasons of safety or to help support the grid – depending on the requirements of the local grid operator.

In addition, in most cases the inverter has a device that can safely interrupt the current from the PV modules. Because PV modules are always live when light is shining on them, they cannot be switched off. If the inverter cable is disconnected during operation, this can lead to dangerous light arcs forming, which do not go out on account of the direct current. If the cutout device is integrated directly in the inverter, installation and wiring efforts are reduced considerably.

4. Communication
Communication interfaces on the inverter allow control and monitoring of all parameters, operational data, and yields. Data can be retrieved and parameters can be set for the inverter via a network connection, industrial fieldbus such as RS485, or wireless via SMA Bluetooth®. In most cases, data is retrieved through a data logger, which collects and prepares the data from several inverters and, if desired, transmits them to a free online data portal (e.g. Sunny Portal from SMA).

5. Temperature management
The temperature in the inverter housing also influences conversion efficiency. If it rises too much, the inverter has to reduce its power. Under some circumstances the available module power cannot be fully used.

On the one hand, the installation location affects the temperature – a constantly cool environment is ideal. On the other hand, it directly depends on the inverter operation: even an efficiency of 98 percent means a power loss of two percent –in form of heat. If the plant power is 10 kW, the maximum thermal capacity is still 200 W. Therefore, an efficient and reliable cooling system for the enclosure is very important – such as SMA’s “OptiCool” cooling concept. The optimum thermal layout of the components allows them to dissipate their heat directly to the environment, while the whole encasing acts as a heat sink at the same time. This allows the inverters to work at maximum rated capacity even at ambient temperatures of up to 50° C.

6. Protection
A weather-proof enclosure, ideally built in line with protective rating IP65, allows the inverter to be installed in any desired place outdoors. The advantage: the nearer to the modules the inverter can be installed, the lower the expenditure for the comparatively expensive DC wiring.

Multi Cluster Box for Off-Grid PV

SMA Solar Technology AG has released the Multi-cluster Box, an off-grid AC distribution hub that manages a variety of renewable and combustion generation sources for large-scale Sunny Island multi-cluster systems.

Now available for the North American market, the SMA Multi-cluster Box features a pre-configured design that the company says simplifies the installation of off-grid renewable energy systems, providing users with design flexibility and making rural electrification simple and scalable.
Ideal for systems up to 110 kW, the Multi-cluster Box offers simple connection of multiple renewable energy sources, backup combustion generators and electrical loads into one battery-supported AC grid. It allows two, three or four three-phase clusters, each consisting of three Sunny Island inverters, to be connected in parallel.
“By dividing the inverter capacity into clusters, the system becomes extremely flexible with respect to performance,” notes Jurgen Krehnke, president and general manager of SMA America and president of SMA Canada. “This design scheme is highly scalable, thanks to the parallel connection of multiple clusters. Subsequent expansion of the off-grid system is also easy to implement, making it ideal for rural electrification.”
The SMA Multi-cluster Box is assembled in SMA’s production facility in Denver.

Right invertor for roof top PV system

Inverter selection for installation of roof top PV system will depend upon

• Energy output of the array
• Matching of allowable inverter string configuration with size of the solar array in KW and size of individual modules with array.
• Whether we decide to have one central inverter or small multiple inverters.

Why multiple inverters make sense?

• If array is spread over number of roofs that have different orientations and tilt angles then the maximum power points and output currents will vary. If it is economical, installing a separate inverter for each section of the array which has the same orientation and angle will maximize the output total of array. Inverters with multi power point trackers will assist us in achieving this
• They allow system to operate even if one inverter fails
• They improve the balance phase in accordance with local requirements
• They allow system to be modular, so that increasing the system will involve adding predetermined number of modules with one inverter

There is one downside to it, that low power rating inverters will be more expensive.

Inverter Sizing:  Currently available are rated for-

• Maximum DC input power
• Maximum DC input current
• Maximum specified output power i.e. the AC power they can provide to the grid

The maximum power of the array is calculated using the following formula:

Array Peak Power = Number of modules in the array x the rated maximum power (P_mp) of the selected module at STC.

The designer shall follow the manufacturer’s recommendation when matching the peak power rating of the array to that of the inverter.

Many manufacturers will provide the maximum rating of a solar array in peak power for a specific size inverter.

In De-rating module performance, the typical PV array output in watts is De-rated due to:

• Manufacturer’s tolerance of the modules
•  Dirt and Temperature.

Renewable Energy Investments goes down

2013-04-17 (canadian association for renewable energies) Global investment in renewable energies is down 38% from Q1 of last year, according to Bloomberg New Energy Finance, a sharper decline that the 22% decline in energy investments worldwide. It was the weakest quarter for clean energy investment since 2009, although most of Asia (excluding China) surged in renewable energy investment, led by Japan. The overall downturn is due to lower financing in large wind and solar projects, the effects of policy uncertainty in key markets such as the US and Germany, and the effect of recent sharp declines in technology costs, particularly those of solar PV panels. Bloomberg CEO Michael Liebreich says Q1 2013 investments for renewables, energy efficiency and energy-smart technologies was $40.6 billion. “For investment in clean energy to play its role in stemming the growth in world GHG emissions, we would need to see investment levels at least double by 2020, rather than fall.” The US experienced a 54% year-over-year decline to $4.5 billion, China retreated by 15% to $8.8 billion, and Europe dropped 25% to $13.4 billion. The largest decline was in the asset finance of utility-scale projects such as windfarms and solar parks, which fell 34% to $19.3 billion.

Utilities Across the US Embracing Solar Energy

For the sixth year in a row, the U.S. Solar Electric Power Association (SEPA) has ranked utilities across the nation in terms of how much solar energy they have incorporated into their user base. This year's report shows that solar is spreading quickly across the country with new entrants from North Carolina, Tennessee and Ohio joining the old standbys.

The rankings break down solar installed capacity into many categories.  SEPA’s Top 10 by Solar Megawatt ranks utilities by installed capacity for solar.  Together the top 10 account for 73 percent of all of the solar capacity that was installed in 2012. Among the top three in the Megawatt rankings are some of the nation’s largest utilities – California’s Pacific Gas and Electric Company with 805 MW installed) and Southern California Edison (194 MW) plus Public Service Electric & Gas Co in NJ, which installed 144 MW.  These utilities often rank highly in this category, says SEPA, due to their expansive customer solar programs and utility purchasing programs.
Rounding out the Megawatt list are:

• Arizona Public Service — 123 MW
• NV Energy — 102 MW
• Jersey Central Power & Light — 98 MW
• Tucson Electric Power Co. — 73 MW
• Progress Energy Carolinas — 69 MW
• Sacramento Municipal Utility District — 65.8 MW
• Hawaiian Electric Co. — 65.1 MW

This is the first year that Progress Energy Carolina’s made the list, whereas all the others were previously ranked in 2011. This is the fifth year that Pacific Gas and Electric Company has topped the list.
SEPA also ranks utilities on a watts-per-customers basis, showing which utilities made significant strides in powering their customers’ homes and businesses with solar energy. Leading the Solar Watts-Per-Customer rankings are many municipal utilities including the City of St. Mary’s, Ohio, with 562 watts per customer, Kauai Island Utility Co-op in Hawaii (282 W per customer) and Bryan Municipal Utilities in Ohio (275 W per customer). Both Ohio utilities were not previously ranked and Kauai moved up from number 12 in the 2011 ratings. The remaining Top 10 providers include Hawaiian Electric Co., Chickasaw (Tenn.) Electric Co-op, Maui (Hawaii) Electric Co., Imperial Irrigation District in Calif., Tucson (Ariz.) Electric Power Co., City of Napoleon in Ohio and Vineland Municipal Electric Utility in N.J.
Julia Hamm, SEPA’s president and CEO said she was “impressed” with the number of utilities that had moved into the top 10. SEPA works to education utility companies about solar energy and help solar companies understand the complexities of the utility business model and it’s work is clearly having an impact.

Global Warming effect on Flights..

One of the side effects of global warming more

On April 8, according to a study published in the journal Nature Climate Change. In the middle of this century, the North Atlantic Airways flights which come across 10 to 40 per cent of the intensity of turbulence, turbulence intensity likely to increase at frequency of 40 percent to 170.

This change will have major impacts on the airline industry. North Atlantic route, more than 600 daily flights to Europe are American.
This encounter turbulence caused by air currents are moving at different speeds. Unnoticeable the turbulence by radar or satellite is very difficult and rarely understood. Clear air turbulence in approximately 3% of flight time in airplanes, with 1% of spending in order to cope with the severe air turbulence.
Clear air turbulence, will further increase with global warming  which results in jet stream of air movements.

Net Metering

Government is providing number of benefits to investors to promote solar industry in India. Net metering is one of the benefits provided by government. Net meter is very useful and encouraging for the household and small scale users to install solar system to power their houses. So, I am writing this article for understanding of Net Metering.

Net metering means the utility company charges you the difference between what you consume from the grid and the electricity you feed in grid. In one Net metering is a meter arrangement where only ‘excess’ of solar electricity is feed into grid is metered. Solar power is first send to the load (appliance, lights etc) and if excess remains, it will be feed into the grid and this amount will be recorded. This will help to reduce bill by two ways:

1. Using solar energy for the load requirement, will reduce electricity consumption from grid
2. Payment against the electricity feed into the grid.

Andhra Pradesh Net Metering Policy

Government of Andhra Pradesh has announced its policy for encouraging solar power production in the State.With the view of good potential for harnessing Solar Energy, it felt that net metering should be provided to consumers for self consumption and feeding excess power into the grid when it is  not consumed by them.

APTRANSCO has installed 100 kW solar plant at Vidyut Soudha, Hyderabad on a pilot basis and has implemented the net metering facility.   CMD, APTRANSCO has proposed that net metering facility can be implemented for the consumers who intend to encourage solar green energy and set up solar PV plants at unutilized places on roof-tops, waste lands, buildings of individual households, industries, offices, institutions, residential complexes etc., considering that there exists subsidy from the Government of India through NREDCAP up to 30% of the cost the panel , till the  capacity of 500 KW without battery support.

After carefully examing Government  permits implementation of Net Metering Facility for the consumers who strive to encourage the solar green energy and set-up solar PV plants.

Guidelines for Implementation of this Facility:

1.  Consumer will generate solar power for self consumption and feed excess power into the grid. 
2. Net metering  records net energy between export of generated energy and import of DISCOM energy for a billing month. Alternatively, the meter, having the feature of recording both the import and export values, besides other parameters notified by CEA metering regulations and APTRANSCO /DISCOM procedures in vogue, shall also be allowed for arriving net energy for the billing period.
3. Net metering facility is allowed only for 3-Phase consumers, making single phase consumers ineligible.
4. The SPV generator shall pay for the net energy in a billing month as per applicable retail supply tariff decided by regulatory commission to the concerned DISCOM, if the supplied energy by the licensee is more than the injected energy by the solar PV sources of the consumers.  Any excess/ surplus energy injected in to the grid in a billing month will be treated as inadvertent and no payment will be paid for such energy.
5. It is mandatory for the  generator  to provide an appropriate protection system on their incoming side/ consumer premises with the feature of “Islanding the SPV generator” when grid fails.
6.  The  generator shall bear the entire cost of metering arrangement provided including its accessories. The installation of meters including CTs & PTs, wherever applicable, shall be carried out as per the latest departmental procedures  with prior permission of DISCOMS.
7.    Such SPV generator will submit the required information in the prescribed format to the DISCOM & DISCOM will give acknowledgement for the same for the net metering as per the applicable billing period.
8. The Solar PV panels proposed to be installed shall meet the requirements of Indian as well as IEC standards.
9.   Any existing subsidy  provided by the Government of India, maybe obtained.

Optimization of PV system for minimizing the shading losses

In solar PV system, it is important to analyze the shading caused by surrounding objects and/or vegetation. Shading on the photovoltaic system is the main hurdle for the power generation. It should be eliminated as much as possible. Right time to consider this issue is the system planning’s phase, later it is usually too late.

Shading of strings - if crystalline modules are mounted on the roof, they should be always mounted horizontally and never vertically. Reason is quite simple: each crystalline module usually includes two bypass diodes which are active if shading occurs. When modules are mounted horizontally the module still operates with some amount of power (50% or less) if the bottom row is shaded, because only one bypass diode is active. But if modules are mounted vertically and if lower row is shaded partially or completely both bypass diodes are active and amount of output power is close to zero.

Preferred orientation of modules in strings on the roof

 String configuration - modules that are shaded more often than other parts of array should be connected into separate string(s) if possible. This will prevent losses of the whole system because of partial shading of only one part of array.

Inverter configuration - some inverter offer several inputs, for each string it have its own input. In case of shading of one string, other inputs will still operate in maximum power point situation.

Amorphous modules – In cases where shading cannot be avoided use of amorphous modules should be considered. Amorphous modules are far less sensitive on partial shading (in comparison with crystalline modules) so that even in case of partial shading they produce significant amount of power.

Array shape – In some cases, we can also prevent shading losses with carefully array design. In the case explained below have array in the shape of trapezoid, because of shading of church’s bell tower.

 

Optimization of array shape in the roof integrated solar modules.

Indian Energy Exchange enters into international tie - up with the European Power Exchange (EPEX SPOT)

New Delhi, April 03rd 2013

The Indian Energy Exchange (IEX) India’s No.1 Energy Exchange has entered into Memorandum of Understanding (MoU) with the European Power Exchange (EPEX SPOT)

on 16 February,2013. EPEX SPOT is the marketplace for short-term power trading in France,Germany, Austria and Switzerland.

Under the proposed tie-up, both companies will work closely together on identifying opportunities that aim at enhancing information and knowledge sharing on the development of electricity trading through competitive market platforms. IEX and EPEX SPOT will also share experience of electricity market operations, explore market development opportunities and training opportunities for IEX personnel as well as for the market participants in the form of direct training or joint training programs in India and neighboring countries. The MoU was signed between Mr.Jean-François Conil-Lacoste, Chairman of the Management Board of EPEX SPOT and Mr Rajesh K.Mediratta,Director Business Development, IEX

 

About IEX

IEX is India’s first and number one power exchange offering nationwide automated and online electricity trading throughout India. IEX is promoted by Financial Technologies (India) Ltd. and PTC Financial Services Ltd. (PFS). Its key stakeholders include Adani Enterprises, Infrastructure Development Finance Company (IDFC), Lanco Infratech, Jindal Power Ltd., Reliance Infrastructure, Rural Electrification Corporation (REC), Light Speed Venture Partners, Bessemer Venture Partners & Multiples, Tata Power Company. IEX was incorporated on 26th March,2007. The exchange is demutualized, and offer complete neutrality, and transparency in transactions. Financial Technologies provide technology support to IEX. ]

 

About EPEX SPOT

The European Power Exchange (EPEX SPOT) is the marketplace for fair, transparent and secure short term power trading in France, Germany/Austria and Switzerland. EPEX SPOT

enables electricity producers, utilities, trading companies and industrial consumers to trade power for today or the following day, by placing their bids every day of the week, all year round:on the daily auction for the next day, or in continuous intraday trading for the upcoming hours,thus balancing their supply and demand. As the markets of EPEX SPOT account for more than one third of the European electricity consumption, the prices fixed by EPEX SPOT have a reference character for the European wholesale market

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REC Policy Needs Immediate Government Interventions in Order to Boost Solar Projects in India

The REC Mechanism based projects are finding tough to survive, as in past months the RECs traded in October were about 15 Lac while RECs were available for the same, however only 2.2 Lac have been redeemed similarly is the case of non-solar RECs
The graphs given below clearly shows the dynamics of REC (solar and non-solar RECs) markets. Solar RECs shows a downward trend in the clearing price after increase in the price up to November 2012. The graph shows increase in the difference of Buy Bids and Sell Bids, as there is increase in Buy Bids there is decrease in Sell Bids.

Non Solar RECs shows a decreasing trend in the cleared volume of Bids and then a slight increase as December approaches. Non solar RECs were cleared at the price of Rs 1500/REC from Sept to Dec 2012.
The RECs will lapse in March and the obligatory agencies, such as Discoms are yet to come forward to buy RECs to meet their RPO Obligations. Recently NLDC, IEX and PXIL have filed petition to CERC for immediate interventions so that CERC can take immediate interventions to extend the validity period of RECs. There are various ways in which the government can extend clarity in its REC regulations which are as follows

1. The lack of clarity of REC related beyond 2017: Announcing five year targets do not help the project developer to get financing, there is a need to announce REC targets and obligations at least for 10 years period. As REC rates are primarily representing viability gap the rates for 10 years can be announced in the form of levellised rate of REC with the floor and forbearance price.
2. The impact of REC / RPO Obligation on Discoms is not more than 15 – 20 paisa / kWh in in terms of overall tariff. It is proposed that the Discoms are allowed to charge Renewable cess of Rs 0.15 / unit which will generate enough revenue for them to purchase RECs and promote the Renewable projects without burdening heavily the consumers
3. While there is slight down in the prices of solar projects the floor and forbearance price of RECs need to be changed  taking into consideration the other benefits such as freewheeling banking charges, subsidies T&D charges etc for the projects under REC route.
4. As RECs are issued on monthly basis the Discoms targets should also be fixed on monthly basis so that the continuous track of monthly RPO fulfilment can be ensured. The current mechanism allows the Discoms to fulfil its obligation in the year end i.e. in March and maximum trading takes place in the FY end. This does not provide regular revenue to the project investors.
5. REC mechanism does not take into consideration to the investors who wish to install off grid systems / Roof top systems (RTS) of smaller capacity. It is proposed that off grid / grid connected RTS should be brought in the purview of RPO compliance of Discom so that individual Roof top owner can own the roof top solar projects and can avail REC benefits.
6. The RPO obligation is also applicable on the captive / open access consumers having 1 MW and above capacity however there is no enforcement of RPO on these categories of consumers if government can enforce seriously The RPO obligation on this category as well then the faith of investors in renewable can be maintained otherwise eth whole REC mechanism van lead to as flop show.

Ozone: Good Up High, Bad Nearby

What is Ozone?

Ozone is a gas that forms in the atmosphere when 3 atoms of oxygen are combined (0₃). It is not emitted directly into the air, but at ground level is created by a chemical reaction between oxides of nitrogen (NO_x), and volatile organic compounds (VOC) in the presence of sunlight. Ozone has the same chemical structure whether it occurs high above the earth or at ground level and can be "good" or "bad," depending on its location in the atmosphere.

How Can Ozone Be Both  Good and Bad?

 Ozone occurs in two layers of the atmosphere. The layer surrounding the earth's surface is the troposphere. Here, ground-level or "bad" ozone is an air pollutant that damages human health, vegetation, and many common materials. It is a key ingredient of urban smog. The troposphere extends to a level about 10 miles up, where it meets the second layer, the stratosphere. The stratospheric or "good" ozone layer extends upward from about 10 to 30 miles and protects life on earth from the sun's harmful ultraviolet rays (UV-b).

Too much here... Cars, trucks, power plants and factories all emit air pollution that forms ground-level ozone or smog.

Too little there... Many popular consumer products like air conditioners and refrigerators involve CFCs or halons during either manufacture or use. These chemicals damage the earth's protective oxone layer.

 

What is Happening to the "Good" Ozone Layer?

 

Ozone occurs naturally in the stratosphere and is produced and destroyed at a constant rate. But this "good" ozone is gradually being destroyed by manmade chemicals called chlorofluorocarbons (CFCs), halons, and other ozone depleting substances (used in coolants, foaming agents, fire extinguishers, and solvents). These ozone depleting substances degrade slowly and can remain intact for many years as they move through the troposphere until they reach the stratosphere. There they are broken down by the intensity of the sun's ultraviolet rays and release chlorine and bromine molecules, which destroy "good" ozone. One chlorine or bromine molecule can destroy 100,000 ozone molecules, causing ozone to disappear much faster than nature can replace it.

It can take years for ozone depleting chemicals to reach the stratosphere, and even though we have reduced or eliminated the use of many CFCs, their impact from years past is just starting to affect the ozone layer. Substances released into the air today will contribute to ozone destruction well into the future.

Satellite observations indicate a world-wide thinning of the protective ozone layer. The most noticeable losses occur over the North and South Poles because ozone depletion accelerates in extremely cold weather conditions. 

How Does the Depletion of "Good" Ozone Affect Human Health and the Environment?

As the stratospheric ozone layer is depleted, higher UV-b levels reach the earth's surface. Increased UV-b can lead to more cases of skin cancer, cataracts, and impaired immune systems. Damage to UV-b sensitive crops, such as soybeans, reduces yield. High altitude ozone depletion is suspected to cause decreases in phytoplankton, a plant that grows in the ocean. Phytoplankton is an important link in the marine food chain and, therefore, food populations could decline. Because plants "breathe in" carbon dioxide and "breathe out" oxygen, carbon dioxide levels in the air could also increase. Increased UV-b radiation can be instrumental in forming more ground-level or "bad" ozone.

   

What Causes "Bad" Ozone?

Motor vehicle exhaust and industrial emissions, gasoline vapors, and chemical solvents are some of the major sources of NO_x and VOC, also known as ozone precursors. Strong sunlight and hot weather cause ground-level ozone to form in harmful concentrations in the air. Many urban areas tend to have high levels of "bad" ozone, but other areas are also subject to high ozone levels as winds carry NO_x emissions hundreds of miles away from their original sources.
Ozone concentrations can vary from year to year. Changing weather patterns (especially the number of hot, sunny days), periods of air stagnation, and other factors that contribute to ozone formation make long-term predictions difficult.

How Does "Bad" Ozone Affect Human Health and the Environment?

Repeated exposure to ozone pollution may cause permanent damage to the lungs. Even when ozone is present in low levels, inhaling it triggers a variety of health problems including chest pains, coughing, nausea, throat irritation, and congestion. It also can worsen bronchitis, heart disease, emphysema, and asthma, and reduce lung capacity.
Healthy people also experience difficulty in breathing when exposed to ozone pollution. Because ozone pollution usually forms in hot weather, anyone who spends time outdoors in the summer may be affected, particularly children, the elderly, outdoor workers and people exercising. Millions of Americans live in areas where the national ozone health standards are exceeded.
Ground-level ozone damages plant life and is responsible for 500 million dollars in reduced crop production in the United States each year. It interferes with the ability of plants to produce and store food, making them more susceptible to disease, insects, other pollutants, and harsh weather. "Bad" ozone damages the foliage of trees and other plants, ruining the landscape of cities, national parks and forests, and recreation areas.

 What Can You Do?

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High-Altitude "Good" Ozone

• Make sure that technicians working on your car air conditioner, home air conditioner, or refrigerator are certified by an EPA approved program to recover the refrigerant (this is required by law).
• Have your car and home air conditioner units and refrigerator checked for leaks. When possible, repair leaky air conditioning units before refilling them.
• Contact local authorities to properly dispose of refrigeration or air conditioning equipment.
• Protect yourself against sunburn. Minimize sun exposure during midday hours (10 am to 4 pm). Wear sunglasses, a hat with a wide brim, and protective clothing with a tight weave. Use a broad spectrum sunscreen with a sun protection factor (SPF) of at least 15 and 30 is better.

Ground-Level "Bad" Ozone

• Keep your automobile well tuned and maintained.
• Carpool, use mass transit, walk, bicycle, and/or reduce driving, especially on hot summer days.
• Be careful not to spill gasoline when filling up your car or gasoline-powered lawn and garden equipment. During the summer, fill your gas tank during the cooler evening hours.
• Make sure your car's tires are properly inflated and your wheels are aligned.
• Participate in your local utility's energy conservation programs.
• Seal containers of household cleaners, workshop chemicals and solvents, and garden chemicals to prevent VOC from evaporating into the air. Dispose of them properly.

We live with ozone every day. It can protect life on earth
or harm it, but we have the power to influence
ozone's impact by the way we live.