Author: John Lee, Antonio Da Roza

Originally: CLSA

Date: 8/8/10

Originally: April 2005

Air pollution in Asia

Our air is becoming worse because of energy generation for economic prosperity especially in Asia. Businessmen can play an active role in using cleaner fuels, conserving energy. Governments need to use renewable energy such as wind energy, solar energy and biofuels, and promote energy efficiency. Gas is a clean fuel but coal is still a dominant source. Clean coal technology is crucial for the future. Asia will play an important role in climate change and many business opportunities will be provided.

Air pollutants and pollution

There are two categories of air pollutant:

Primary pollutants come directly into the atmosphere from identifiable emitting sources (eg. power plants, vehicles). Primary pollutants include carbon monoxide, sulphur dioxide, nitrogen oxides, volatile organic compounds, particulates and lead. Other pollutants such as PCBs and CFCs also contribute to climate change.

Secondary pollutants are created in the atmosphere when primary pollutants react with each other or with atmospheric compounds such as water vapour. eg. chemicals that make up acid rain and smog.

The main types of pollutants are:

- Carbon monoxide: is often generated from transport uses such as petrol and diesel. It interferes with the oxygen-carrying capacity of the blood. At greatest risk are people suffering from cardiovascular weaknesses and diseases, elderly people, pregnant women and children.

- Sulphur dioxide: comes from the combustion of sulphur containing fuels. Exposure to high concentrations of sulphur dioxide may aggravate existing respiratory and cardiovascular problems and affect breathing and weakens lungs’ defences. Irritates the nose, nasopharynx and bronchi; and increases likelihood of cancer. At greatest risk to these health effects are children, the elderly, asthmatics and allergy sufferers.

- Nitrogen oxides: primary sources are combustion of diesel fuels, with power generation and vehicles. The compounds of nitrogen oxides result in acid rain that damages building materials and water based ecosystems. Nitrogen oxides give polluted air its brown tinge. Nitrogen oxides can irritate lungs and lower resistance to respiratory infections such as flu. Continuous or frequent exposure to high levels may cause increased incidence of acute respiratory disease in children. At greatest risk to these health effects are children who suffer from asthma, emphysema and chronic bronchitis.

- Volatile organic compounds (VOCs): come from incomplete combustion and reach the atmosphere through fuel evaporation. VoCs adhere to particulate matter (PM) and enter the lungs during inhalation. Some VOCs are carcinogenic.

- Particulate matter (PM): are the solid particles and liquid droplets in the air. PM is frequently the most obvious form of air pollution because they reduce visibility and leave dirt on surfaces. PM sources may be primary or secondary. The finer the particles, the more dangerous they are to health. The WHO now believes there is no safe level of PM. The finer particles are able to reach the lower parts of the respiratory tracts, affecting breathing and aggravating existing respiratory and cardiovascular illnesses. PM can also alter the body’s defence against foreign materials, as well as damage lung tissues. They may also be carcinogenic and can absorb gaseous pollutants (such as SO2) and deliver them directly into the lungs. At greatest risk to these health effects are children, the elderly and persons with pulmonary or cardiovascular illnesses.

- Lead: mainly comes from leaded fuels. Lead accumulates in blood, bone and soft tissues. It is not readily excreted and can affect the blood, kidneys, liver and nervous system.

- Smog: the major component of smog is ozone. Short term exposure to ozone causes eye and lung irritation. Longer term recurring exposure can cause chronic health problems. CO, SO2, NOx and VOCs are all precursors to smog.

How is air pollution measured?

Air quality standards set legal limits of the volume of pollutants in ambient air to protect human health.

In Hong Kong, Air Quality Objectives (AQOs), which are not legally enforceable, set the standards for seven air pollutants in 1987 under the Air Pollution Control Ordinance (APCO) based on then-prevailing international standards.

We know the amount of pollutants in the air by checking out a city’s API (Air Pollution Index) which is easy for the public to understand. When the index reaches 200 or higher, an air pollution alert is issued.

How bad is air pollution in Asian cities?

Asia currently holds half of the world’s urban population. Air quality is worse in urban areas and in Asia due to the large population base and high urban density. For the long term air quality trends, 9 Asian cities were selected for the report. All are making progress in lowering the sulphur dioxide emissions and nitrogen oxide emissions modestly. PM levels are still high in many places. Ozone levels have either gone up or remained the same.

Even when there is compliance with the average air quality standards, this does not necessarily mean the air quality is good. For example, street level air quality can be very poor and affects people who work or live near busy roads.

A simple way to monitor a city’s compliance with the short term air quality standards is to analyse API data. It is up to individual cities to interpret levels of air pollutant and corresponding health implications. APIs are generally calculated based on prevailing air quality standards. Thus APIs may not be reliable if a city sets unreasonably low standards for pollutant concentration.

Many cities cannot meet all their air quality standards due to greater demands on energy consumption. This can be seen in Hong Kong and Shenzhen where there has been tremendous growth in the last two decades.

Facing the challenge

The challenge is huge in Asia because of the growing population size, GDP per capita growth trend especially in China and India, greater energy consumption and more pollutant emissions. China is the world’s second largest oil-consuming nation. As the economy grows, an increased number of vehicles will result in a larger consumption of fuel.

In Hong Kong, ultra low sulphur diesel with 0.005% sulphur is the only diesel sold for vehicles. Sulphur levels in fuel sold in China is 50-500 times higher than Hong Kong. The price differential presents an incentive for cross-border commercial vehicles to fill up at mainland stations or buy from the illegal trade that supply fuels with very high sulphur content.

Hong Kong’s sulphur content regulation in July 1990 (sulphur content in fuel dropped from 2.5% to 0.5% by weight) brought about a marked improvement in lung function and a reduction in clinical symptoms of bronchitis in primary school children (aged 8-10) and a reduction in bronchitic symptoms in their mothers. The annual trend in mortality across the whole population declined by an average of 2.2% (more than 4% in older people), reflecting a reduction of about 600 deaths per year.

Risks and opportunities

Coal will remain a key energy resource for China in the foreseeable future. Using clean coal technologies is important to reduce environmental damage as coal of lower quality has high sulphur content. A well developed technology is flue gas scrubbing to remove sulphur dioxide and nitric oxide.

Industries should switch to cleaner fuels. Responsible businesses can consider voluntary fuel substitution to burn cleaner fuels.

The shipping industry needs to clean up its fuel usage. Currently, ships use fuel with 4.5% sulphur content or even dirtier. China can declare Hong Kong and the Pearl River Delta waters a special sulphur emission control area for shipping.

Aviation and airports can also help reduce emissions by retrofitting airports.

Political control measures should help as pollution in one place can affect another place. Energy can be used much more efficiently. Scientists estimate that 84% of all commercial energy used in the US is wasted. Coal burning is one of the biggest energy wasters in the US.

Technology is also fast developing for co-generation where industries such as power generation or cement making, are recovering waste heat for re-use at the same time as energy is being consumed.

Renewable energy should be invested in. Solar power appears to be the most interesting, with declining costs of production and strong government support in many markets.

The countries which signed the Kyoto Protocol should implement and pursue better policies to achieve reductions. Clean development mechanisms designed for developing countries where they can sell carbon emission reduction credits as part of investments in financial projects should be implemented.


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