The temperature of urban areas in Hong Kong has been increasing in recent years and this is the Urban Heat Island (UHI) effect. Apart from causing the rise of temperature in urban areas, UHI effect also induces some undesirable impacts to Hong Kong citizens who are living in the urban areas. We shall never underestimate the potential dangers caused by the UHI effect and we should treat it more seriously. This paper will give a brief introduction on UHI effect, its influence and the possible measures that can deal with it.
WHAT IS URBAN HEAT ISLAND (UHI) EFFECT?
Urban Heat Island (UHI) effect describes predominately at night, the temperature difference
between the urban areas and the rural ...view middle of the document...
All these factors contribute to the significant difference between the temperatures in
urban and rural areas.
Statistics regarding the UHI effect
According to the press released by the Hong Kong Polytechnic University in 2008, their researchers carried out an investigation on the UHI intensity in Hong Kong and recorded the average temperature difference between the urban and rural areas was 7 °C to 8 °C in winter nights, and the maximum difference was at 12 °C, while in summer nights, the difference was 5 °C to 6 °C (The Hong Kong Polytechnic University, 2008). The temperature difference was in such a considerable amount!
Green Power also had monitored the UHI effect in Hong Kong for nine years. According to their reports in 2012, for every kilometre moving from the edge of the city towards the centre, the temperature increases from 2 °C to 6 °C (Green Power, 2012).
Source: The Hong Kong Observatory
The above graph is obtained from the Hong Kong Observatory. This graph showed the
temperature falling rate on the two winter days in 2001. Clearly, the temperature at Ta Kwu Ling (rural area) decreased very quickly at night but the temperature at the Hong Kong Observatory (urban area) dropped very slowly at night!
WHAT ARE THE INFLUENCES OF UHI EFFECT?
UHI effect has significant and deep influences on Hong Kong in different aspects.
Unquestionably when the temperature of our city increases, it will be easier for people
working outside to get heat stroke. At such a hot condition, people working outdoors will have a lower working efficiency.
When the city is getting hotter and hotter, the demand on air-conditioning increases,
which will first increase the amount of energy consumed, and second increase the amount of waste heat produced which will further strengthen the UHI effect! This is simply a negative feedback!
More and more air particulates and pollutants accumulate in the air since the wind speed is low. Hence, people may suffer from respiratory diseases easily. Apart from this, air pollutants may also be trapped by temperature inversion (ref).
WHAT CAN WE DO TO REDUCE THE UHI EFFECT?
There are a wide variety of measures to reduce the UHI effect; some can be achieved by individuals while some require the cooperation between the government and commercial companies.
Government can set up laws, forbidding the use of materials with high heat capacity in buildings. Hence, buildings will absorb lesser amount of heat in daytime and will be cooled down faster at night. Moreover, government should also limit the heat emission by vehicles (burning of fuels) and buildings (air-conditioning and kitchen work) according to their scale, preventing over-emission of heat.
By planting more greenery, the temperature of the city would decrease. This is because plants are able to cool down the surrounding air through transpiration. During urban planning, the government should...