• Home   /  
  • Archive by category "1"

Essay On Need For Conservation Of Ozone Layer

Ozone Layer Protection and You

Content

(1) What is meant by "ozone hole"?

Since about 1975, scientists have detected a severe drop in ozone concentration in the layer over the Antarctica each spring. The situation then reached an alarming scale in 1987 when an international expedition found that half of the Antarctica's ozone have disappeared over a region twice the size of the United States, creating an enormous "hole" in the ozone layer.  Concentrations of ozone fell by as much as 50% of the norm at altitude of 18 km.  At mid-latitudes in the Northern Hemisphere, up to 3% decrease in ozone concentration was also observed.

          (Severe Drop in Ozone Concentration)
Acknowledgement:
Permission to use the image of "ozone hole" from the Ozone Processing Team, Goddard Space Flight Centre, NASA, and the ozone depleting illustration schematic from the Centre for Atmospheric Science, Chemistry Dept., University of Cambridge ("Ozone Hole Tour" website address,http://www.atm.ch.cam.ac.uk/tour/) is gratefully acknowledged.

(2) Why it concerns you?

The ozone molecules form a protective layer which extends from about 16 km to 50 km up above the earth at low latitudes, and from about 8 km to 50 km at high latitudes. The ozone molecules absorb the sun's ultra violet radiation (UV) which will be harmful to us if it reaches the earth surface.  With more UV radiation reaching the earth surface due to ozone depletion, human health and the environment will be adversely affected. The most significant effects will be the increased incidence of skin cancer, eye cataracts, damage to the human immune system and to the ecology of the earth.

(3) What causes this phenomenon?

Scientists have reached consensus that ozone depletion in the stratosphere is caused by ozone depleting chemicals.  These chemicals contain chlorine or bromine atom with inherent chemical stability and have long lifetime in the atmosphere, in the range of 40 to 150 years. These chemicals and other trace gases drift up into the stratosphere and become involved in chlorine-releasing reactions. The chlorine atoms then react with the ozone molecules in the presence of sunlight and destroy the ozone molecules. Just one chlorofluorocarbon molecule can destroy tens of thousands of ozone molecules.

These ozone-depleting chemicals are extensively used man-made chemicals including the followings: -

  • chlorofluorocarbons (CFCs);

  • halons;

  • 1,1,1-trichloroethane (methyl chloroform);

  • carbon tetrachloride;

  • methyl bromide;

  • hydrobromofluorocarbons (HBFCs);

  • hydrochlorofluorocarbons (HCFCs); and

  • bromochloromethane (BCM).

Ozone depleting substances destroy the ozone molecules and allow more UV radiation reaching the earth

(4) What are these ozone depleting substances (ODS) used for?

The following are the common usage of CFCs and HCFCs :

  • CFC-11, CFC-12 and HCFC-22 are used as refrigerant in domestic air-conditioners and refrigerators as well as retail store refrigeration systems, chillers and air-conditioners.
  • CFC-11 and CFC-12 are used as propellants for aerosol sprays such as hair mousses and household cleaning products.
  • CFC-11 and CFC-12 are also used as blowing agents in the manufacture of foams for home furnishing, insulation and packaging. Some plastics may be shaped using CFCs, e.g. egg cartons, cups and cartons used in fast food operations. Rigid or semi-rigid foams are also used as thermal or sound insulation in refrigeration equipment, buildings and automobiles.
  • CFC-113 is a solvent for cleaning electronic circuit boards and computer components.

Halons are used as fire extinguishing agents. Bromochlorodifluoromethane (BCF) is commonly used in portable fire extinguishers. Bromotrifluoromethane (BTM) is used in fixed fire-fighting installations.1,1,1-trichloroethane is commonly used as a:

  • solvent for cleaning electronic circuit boards and metal work such as watches and clockworks.
  • thinner such as that for correction fluid.
  • cleaning agent in the textile industry (dry cleaning).

Carbon tetrachloride is used as a cleaning agent in textile and electronics industries.

(5) Can we get rid of the ODS?

There has been considerable progress in finding non-ozone-depleting substitutes for ODS in the last few years. Substitutes for air-conditioning and refrigeration applications are now available, such as that HCFC-22 can be replaced by HFC-410A, CFC-12 can be replaced by HFC-134a. There are also emerging markets for "drop-in" replacement for HCFCs and halons.

Alternative products or processes can be used in some cases including the following:

  • alternative insulating materials;

  • substitute food containers such as hydrocarbon blown polystyrene, plastic film wrap and bags;

  • alternative packaging materials such as plastic film bubble wraps; and

  • air-conditioning and refrigeration plants operating on non-HCFC refrigerants.

HCFCs solvents can be substituted in some applications. For instance, petroleum solvents can be selected as a replacement for CFC-113 or 1,1,1-trichloroethane in cleaning applications. Aqueous cleaning, or even no-clean technology, are also alternative processes that can be used by the electronics industry.

Many household and personal aerosol products, e.g. paint sprays and insecticides, now use hydrocarbons (e.g. propane and butane) as propellants instead of HCFCs or CFCs.

(6) What are the international efforts in saving the ozone layer?

In September 1987, an international treaty aimed at saving the Earth's ozone layer, known as the Montreal Protocol on Substances that Deplete the Ozone Layer, was signed in Montreal, Canada.  The Protocol requires the phasing out of the ODS in accordance with agreed schedules.  Following lists the ODS phasing out schedules applicable to Hong Kong:

Halons

Import for local consumption banned by 1.1.1994

CFCs

CarbonTetrachloride

1,1,1-Trichloroethane

HBFCs

Import for local consumption banned by 1.1.1996

Methyl Bromide

Import restricted to local quarantine and pre-shipment applications only by 1.1.1995

HCFCs

Freeze consumption at base level starting 1.1.1996

35% reduction of import for local consumption by 1.1.2004

75% reduction of import for local consumption by 1.1.2010

90% reduction of import for local consumption by 1.1.2015

100% reduction of import for local consumption by 1.1.2020[1]

[1] May allow 0.5% for servicing in the period 2020-2030. Such need will be reviewed by the Meeting of Parties to Montreal Protocol in 2015

BCM

Import for local consumption banned by 1.10.2009

(7)How does Hong Kong control the ODS?

To fulfil Hong Kong Special Administrative Region's international obligations under the 1985 Vienna Convention for the Protection of the Ozone Layer and the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, the Ozone Layer Protection Ordinance (CAP. 403)was enacted in July 1989 to provide a statutory framework for the control of ozone depleting substances.The chemicals under control are referred to as "scheduled substances" in the Ordinance (Please see Session 12 - Schedule). The Ordinance prohibits the manufacturing of such substances and imposes controls on the import and export of these substances through registration and licensing provisions.The following is a summary of the related control:

Control of import and export of scheduled substances 
Banning of import for local consumption of halons

1.1.1994

Licensing of import of methyl bromide strictly for local quarantine and pre-shipment applications

1.1.1995

Banning of import for local consumption of CFCs, 1,1,1-trichloroethane,carbon tetrachloride and HBFCs
Licensing of import of HCFCs for local consumption

1.1.1996

Banning of import for local consumption of BCM

1.10.2009

Under the registration and licensing system, persons who wish to import or export any of the ODS must:

In 1993, two pieces of legislation were introduced under the Ozone Layer Protection Ordinance:

  • The Ozone Layer Protection (Products Containing Scheduled Substances) (Import Banning) Regulation

  • The Ozone Layer Protection (Controlled Refrigerants) Regulation

Copies of the Ozone Layer Protection Ordinance and subsidiary regulations are on sale at the Government Publications Centre.  Also, they can be browsed from the web site of Bilingual Laws Information System at http://www.elegislation.gov.hk.

(8) What is the Ozone Layer Protection (Products Containing Scheduled Substances) (Import Banning)(Amendment) Regulation about?

This Regulation prohibits the import of controlled products containing HCFCs, CFCs and halons, etc.:

  • an air-conditioner or heat pump designed to cool the driver's or passengers' compartment of a motor vehicle (whether or not installed in the motor vehicle);

  • refrigeration equipment or air-conditioning or heat pump equipment (whether for domestic or commercial use);

  • an aerosol product including those containing a pharmaceutical product or medicine as defined in section 2 of the Pharmacy and Poisons Ordinance (Cap. 138) ;;

  • insulation panel, insulation board or insulation pipe cover;

  • a pre-polymer;

  • portable fire extinguishers containing CFCs, halons, HCFCs or BCM.

(9) What is the Ozone Layer Protection (Controlled Refrigerants) Regulation about?

This Regulation prohibits any intended release of controlled refrigerants from motor vehicle air-conditioners or refrigeration equipment containing more than 50 kg of refrigerant charge into the atmosphere, and to conserve the controlled refrigerants through the use of approved recycling and recovery equipment.

For enforcement and monitoring purposes, owners or operators of industrial/commercial refrigeration systems, as well as proprietors of garages, shall be required to keep records on relevant repair services and the amount of CFC-based refrigerants consumed.  Proprietors of vehicle scrap-yards shall also be required to keep records on the number of motor vehicle air conditioners decommissioned as well as the amount of CFC-based refrigerants recovered from the decommissioned air conditioners.

(10) How can I help to protect the ozone layer?

While the vast majority of ODS usage is either industrial or commercial, individuals can help in the following ways:

  • Buy air-conditioning and refrigeration equipment that do not use HCFCs as refrigerant.
  • Buy aerosol products that do not use HCFCs or CFCs as propellants.
  • Conduct regular inspection and maintenance of air-conditioning and refrigeration appliances to prevent and minimize refrigerant leakage.

  • For existing air-conditioning and refrigeration appliances that operate on HCFCs or CFCs, the refrigerant should be recovered or recycled whenever an overhaul of equipment is to be carried out. Replacing or retrofitting such equipment to operate on non-HCFCs refrigerant should also be considered.
  • When motor vehicle air-conditioners need servicing, make sure that the refrigerants are properly recovered and recycled instead of being vented to the atmosphere.

(11) FURTHER INFORMATION

Enquiries concerning the Ozone Layer Protection Ordinance and any other general information on the registration and licensing provisions may be made to the Air Policy Group of Environmental Protection Department at the following address: 

33/F, Revenue Tower,2594 62612827 8040
5 Gloucester Road,2594 6225
Wan Chai,Hong Kong2594 6329

Enquiries regarding the application for registration and import or export licences may be made to the Non-textiles Licensing Unit of Trade and Industry Department at the following address:

(12) SCHEDULE

Scheduled Substances

A substance listed in this Schedule includes, except as otherwise stated, the substance's isomers.

PART 1

Chlorofluorocarbons (CFCs)

CFCl3

Trichlorofluoromethane

CFC-11

CF2Cl2

Dichlorodifluoromethane

CFC-12

C2F3Cl3

Trichlorotrifluoroethane

CFC-113

C2F4Cl2

Dichlorotetrafluoroethane

CFC-114

C2F5Cl

Chloropentafluoroethane

CFC-115

PART 2

Halons

CF2BrCl      

Bromochlordifluoromethane

halon 1211

CF3Br

Bromotrifluoromethane 

halon 1301

C2F4Br2

Dibromotetrafluoroethane

halon 2402

PART 3

Other Fully Halogenated Chlorofluorocarbons

CF3Cl

Chlorotrifluoromethane

CFC-13

C2FCl5

Pentachlorofluoroethane

CFC-111

C2F2Cl4

Tetrachlorodifluoroethane      

CFC-112

C3FCl7

Heptachlorofluoropropane     

CFC-211

C3F2Cl6

Hexachlorodifluoropropane

CFC-212

C3F3Cl5

Pentachlorotrifluoropropane  

CFC-213

C3F4Cl4

Tetrachlorotetrafluoropropane

CFC-214

C3F5Cl3

Trichloropentafluoropropane 

CFC-215

C3F6Cl2

Dichlorohexafluoropropane

CFC-216

C3F7Cl

Chloroheptafluoropropane

CFC-217

PART 4

Methyl Chloroform

C2H3Cl3

1,1,1-Trichloroethane

Methyl Chloroform

PART 5

Carbon Tetrachloride

CCl4

Tetrachloromethane

Carbon Tetrachloride

PART 6

Methyl Bromide

CH3Br

Bromomethane

Methyl Bromide

PART 7

Hydrobromofluorocarbons (HBFCs)

CHFBr2                

CHF2Br           

Bromodifluoromethane

HBFC-22B1

CH2FBr           

Bromofluoromethane

      ---

C2HFBr4              

Tetrabromofluoroethane

      ---

C2HF2Br3            

Tribromodifluoroethane

      ---

C2HF3Br2            

Dibromotrifluoroethane

      ---

C2HF4Br          

Bromotetrafluoroethane

      ---

C2H2FBr3            

Tribromofluoroethane

      ---

C2H2F2Br2     

Dibromodifluoroethane

      ---

C2H2F3Br        

Bromotrifluoroethane

      ---

C2H3FBr2            

Dibromofluoroethane

      ---

C2H3F2Br    

Bromodifluoroethane

      ---

C2H4FBr      

Bromofluoroethane

      ---

C3HFBr6         

Hexabromofluoropropane

      ---

C3HF2Br5       

Pentabromodifluoropropane

      ---

C3HF3Br4       

Tetrabromotrifluoropropane

      ---

C3HF4Br3       

Tribromotetrafluoropropane

      ---

C3HF5Br2       

Dibromopentafluoropropane

      ---

C3HF6Br      

Bromohexafluoropropane

      ---

C3H2FBr5

Pentabromofluoropropane

      ---

C3H2F2Br4     

Tetrabromodifluoropropane

      ---

C3H2F3Br3     

Tribromotrifluoropropane

      ---

C3H2F4Br2     

Dibromotetrafluoropropane

      ---

C3H2F5Br    

Bromopentafluoropropane

      ---

C3H3FBr4       

Tetrabromofluoropropane

      ---

C3H3F2Br3     

Tribromodifluoropropane

      ---

C3H3F3Br2     

Dibromotrifluoropropane

      ---

C3H3F4Br    

Bromotetrafluoropropane

      ---

C3H4FBr3       

Tribromofluoropropane

      ---

C3H4F2Br2     

Dibromodifluoropropane

      ---

C3H4F3Br    

Bromotrifluoropropane

      ---

C3H5FBr2       

Dibromofluoropropane

      ---

C3H5F2Br    

Bromodifluoropropane

      ---

C3H6FBr      

Bromofluoropropane

      ---

PART 8

Hydrochlorofluorocarbons (HCFCs)

CHFCl2           

Dichlorofluoromethane

HCFC-21

CHF2Cl       

Chlorodifluoromethane

HCFC-22

CH2FCl       

Chlorofluoromethane

HCFC-31

C2HFCl4         

Tetrachlorofluoroethane

HCFC-121

C2HF2Cl3       

Trichlorodifluoroethane

HCFC-122

C2HF3Cl2       

Dichlorotrifluoroethane

HCFC-123

C2HF4Cl     

Chlorotetrafluoroethane

HCFC-124

C2H2FCl3       

Trichlorofluoroethane

HCFC-131

C2H2F2Cl2

Dichlorodifluoroethane

HCFC-132

C2H2F3Cl

Chlorotrifluoroethane

HCFC-133

C2H3FCl2

Dichlorofluoroethane

HCFC-141

C2H3F2Cl

Chlorodifluoroethane

HCFC-142

C2H4FCl

Chlorofluoroethane

HCFC-151

C3HFCl6

Hexachlorofluoropropane

HCFC-221

C3HF2Cl5

Pentachlorodifluoropropane

HCFC-222

C3HF3Cl4

Tetrachlorotrifluoropropane

HCFC-223

C3HF4Cl3

Trichlorotetrafluoropropane

HCFC-224

C3HF5Cl2

Dichloropentafluoropropane

HCFC-225

C3HF6Cl

Chlorohexafluoropropane

HCFC-226

C3H2FCl5

Pentachlorofluoropropane

HCFC-231

C3H2F2Cl4

Tetrachlorodifluoropropane

HCFC-232

C3H2F3Cl3

Trichlorotrifluoropropane

HCFC-233

C3H2F4Cl2

Dichlorotetrafluoropropane

HCFC-234

C3H2F5Cl

Chloropentafluoropropane

HCFC-235

C3H3FCl4

Tetrachlorofluoropropane

HCFC-241

C3H3F2Cl3

Trichlorodifluoropropane

HCFC-242

C3H3F3Cl2

Dichlorotrifluoropropane

HCFC-243

C3H3F4Cl

Chlorotetrafluoropropane

HCFC-244

C3H4FCl3

Trichlorofluoropropane

HCFC-251

C3H4F2Cl2

Dichlorodifluoropropane

HCFC-252

C3H4F3Cl

Chlorotrifluoropropane

HCFC-253

C3H5FCl2

Dichlorofluoropropane

HCFC-261

C3H5F2Cl

Chlorodifluoropropane

HCFC-262

C3H6FCl

Chlorofluoropropane

HCFC-271

PART 9

Bromochloromethane (BCM) 

CH2BrCl

Bromochloromethane

      ---

EU legislation to protect the ozone layer is among the strictest and most advanced in the world. Europe has not only implemented what has been agreed under the Montreal Protocol on protecting the ozone layer but has often phased out dangerous substances faster than required.

The importance of a healthy ozone layer

The ozone layer in the upper atmosphere protects humans and other organisms against ultraviolet (UV) radiation from the sun. In the 1970s scientists discovered that certain man-made chemicals deplete the ozone layer, leading to an increased level of UV radiation reaching the Earth.

Overexposure to UV radiation carries a number of serious health risks for humans. It causes not only sunburn but also greater incidences of skin cancer and eye cataracts.

There are also serious impacts on biodiversity. For example, increased UV radiation reduces the levels of plankton in the oceans and subsequently diminishes fish stocks. It can also have adverse effects on plant growth, thus reducing agricultural productivity. A direct negative economic impact is the reduced lifespan of certain materials like plastics.

Ozone-depleting substances

Gases that damage the ozone layer - ozone-depleting substances (ODS) - have been used in a wide range of industrial and consumer applications, mainly in refrigerators, air conditioners and fire extinguishers. They have also been used as aerosol propellants, solvents and blowing agents for insulation foams.

The main ODS being phased out under the Montreal Protocol are

  • chlorofluorocarbons (CFCs)
  • hydrochlorofluorocarbons (HCFCs)
  • halons
  • carbon tetrachloride and
  • methyl bromide.

The link to climate change

Most man-made ODS are also very potent greenhouse gases. Some of them are up to 14 000 times stronger than carbon dioxide (CO2), the main greenhouse gas.

Eliminating these substances therefore also contributes significantly to the fight against climate change. The international phase-out of ODS has so far delayed the impact of climate change by 8-12 years.

On the other hand, phasing out ODS has led to a strong growth of other highly warming gases, such as the HFCs (hydrofluorocarbons). In 2016, Parties to the Montreal Protocol agreed to add HFCs to the list of controlled substances.

EU at the forefront

The international community established the Montreal Protocol on substances that deplete the ozone layer in 1987. Policies put in place by the EU and its Member States often go beyond the requirements of the Montreal Protocol.

Already by 2010, the EU had significantly reduced its consumption of the main ozone-depleting substances, 10 years ahead of its obligation under the Montreal Protocol.

Furthermore, the EU has put in place controls on uses of ozone-depleting substances that are not considered as consumption under the Montreal Protocol, such as the use of ODS as a feedstock in the chemical industry.

The EU has also gone beyond the requirements of the Protocol in banning the use of the toxic chemical methyl bromide for any kind of fumigation.

EU legislation has not only been very effective in controlling ozone-depleting substances but has also acted as a driver for the development of innovative technologies. These include

  • alternatives to methyl bromide
  • new blowing agents for insulation foam
  • CFC-free metered dose inhalers for the treatment of asthma, and
  • innovative non-halon fire-fighting systems, for example on ships and airplanes.

But the job is not done yet …

The global consumption of ODS has been reduced by some 98% since countries started taking action under the Montreal Protocol.

As a result, the atmospheric concentration of the most aggressive types of ODS is falling and the ozone layer is showing the first signs of recovery. Nevertheless, it is not expected to recover fully before the second half of this century.

Much remains to be done to ensure the continued recovery of the ozone layer and to reduce the impact of ODS on climate change.

Actions needed are:

  • Ensuring that the existing restrictions on ODS are properly implemented and worldwide use of ODS continues to be reduced;
  • Ensuring that ODS are replaced with climate-friendly alternatives;
  • Recovering ODS from existing equipment and buildings;
  • Preventing illegal trade in ODS;
  • Reducing use of ODS in applications that are not considered as consumption under the Montreal Protocol.

Research

The European Commission supports research projects in the field of ozone layer protection.

Some examples:

  • The RECONSILE project aimed to improve model representations of key processes dominating chemistry, microphysics and the dynamics of Arctic stratospheric ozone loss.
  • SHIVA aimed to reduce uncertainties in present and future stratospheric halogen loading and ozone depletion resulting from climate feedbacks between emissions and transport of ozone depleting substances (ODS).
  • ICEPURE investigated the impact of climatic and environmental factors on personal ultraviolet radiation exposure and human health.

One thought on “Essay On Need For Conservation Of Ozone Layer

Leave a comment

L'indirizzo email non verrà pubblicato. I campi obbligatori sono contrassegnati *