Ozone Layer Protection

The ozone layer in the Earth's atmosphere protects us from the harmful ultraviolet rays from the Sun, but it is at risk of depletion. This article explains the problem, what is causing it, the international and local efforts to reduce the production and use of ozone depleting chemicals, and how you can help to protect the ozone layer.

Ozone Layer Depletion

The ozone layer is a shield of ozone gas in the stratosphere, between 15 and 35 km above the Earth's surface. The result of a reaction between ultraviolet light from the Sun and oxygen molecules, it stops most ultraviolet (UV) radiation reaching us. However, in 1975 scientists detected a severe drop in ozone levels over Antarctica that repeated each Spring, and by 1987 half of the ozone over the continent had disappeared, creating an enormous "hole" twice the size of the United States. This "hole" in the ozone layer threatens the Earth's environmental balance and human health, with increased cases of skin cancer, eye cataracts and damage to the immune system.

Cause of Ozone Layer Depletion

The stratosphere is being depleted of ozone by man-made chemicals including chlorofluorocarbons (CFCs), halons, methyl chloroform, carbon tetrachloride, methyl bromide, hydrobromofluorocarbons (HBFCs), hydrochlorofluorocarbons (HCFCs) and bromochloromethane (BCM). These chemicals are commonly used as cooling agents for refrigerators and air-conditioners, propellants for aerosol sprays, blowing agents in the manufacture of foam and some plastics, fire retardants for extinguishers and in cleaning agents and solvents in industries. In other words, they are widely used in our everyday lives.

Accelerated Phasing Out of HCFCs

In September 2007, the parties to the 19^th meeting of the Montreal Protocol, an international treaty designed to protect the ozone layer, agreed to speed up the phasing out the use of HCFCs. As a result, Hong Kong eliminated 75% of its baseline HCFCs consumption from 2010 instead of the original 65% and reduced 90% of the baseline consumption from 2015. Starting from 1^st January 2020, Hong Kong completely banned the import of HCFCs, with only a small amount of HCFCs (0.5% of baseline consumption) reserved for repairing and maintaining refrigeration and air conditioning equipment until 1^st January, 2030. A crucial aspect of that reduction counts on people like you replacing air-conditioning and refrigeration systems with those that use non-HCFCs refrigerants.

Ozone Layer Protection Ordinance

Hong Kong enacted the Ozone Layer Protection Ordinance (Cap. 403, Laws of Hong Kong) in 1989 to restrict the manufacture, export and import of ozone depleting chemicals. This is achieved through licensing and the registration of related commercial activities. The subsidiary regulations include the Ozone Layer Protection (Products Containing Scheduled Substances) (Import Banning) Regulation and the Ozone Layer Protection (Controlled Refrigerants) Regulation. These two regulations control the import of certain chemicals and their emission to the atmosphere, respectively.

Licensing Control

The Ozone Layer Protection Ordinance applies quotas and licensing restrictions to the import and export of ozone depleting chemicals. Importers of the chemicals listed in the Schedule to the Ordinance must register with the Trade and Industry Department before applying for a licence to receive those chemicals.

What You Can Do

Although most ozone depleting substances are used in industry and commerce, what you do at home can still make a difference. The most effective way of protecting the ozone layer is to reduce or even stop using ozone depleting chemicals. You can do this by:

• buying air-conditioners that do not use HCFCs as refrigerants;
• regularly inspecting and maintaining your air-conditioners and refrigeration appliances to minimise refrigerant leaks; recovering and recycling instead of venting refrigerants in air-conditioners and refrigeration appliances when they are serviced;
• replacing and retrofitting such equipment to operate on environmental-friendly refrigerants.

Overall, the best way to help protect the ozone layer is to stop buying all products, big and small, that contain ozone depleting substances. Together we can make a difference.