2.1 The Formation of UHI
Luke Howard first proposed the urban heat island concept in 1833, he had examined the average temperature between London city and villages in 1920. As the result showed that the London city temperature is significant higher than the rural area in the day and night due to land usage increasing, lack of vegetation, artificial environments and heat production effect the high temperature in urban area than rural area.
Therefore, UHI change the urban district of the micro-climate, impact of the present as including the reduce insolation, cloud amount increased, rainfall increased, slight increase, and the average wind speed as well as the decrease in air quality degradation, and so on (Landsberg, 1981).
2.2 Causes …show more content…
While the increase in pollution levels leads to more incidences of respiratory illnesses, another impact of the urban heat island on public health.
2.3.2 Thermal comfort
These raised temperatures in city centre derive from the altered thermal balances in urban spaces, mainly due to the materials and activities taking place in cities, by far different to those in rural areas. The increasing numbers of buildings and construction in Ipoh caused that vegetation and trees replaced by buildings. Thus, air temperature increases especially in high density areas (Shahmohamadi, et al, 2012).
Humidity effects—although there is little difference in the amount of water that cities and countrysides retain in their atmospheres (absolute humidity), the higher urban temperatures effectively lowers the relative humidity (since warm air can hold more water than cold air).
2.3.3 …show more content…
The formation of smog that is highly sensitive to temperatures since photochemical reactions are more likely to occur and intensify at higher temperatures. Atmospheric pollution can be aggravated due to the accumulation of smog. In addition, the increased emissions of ozone precursors from vehicles is also associated with the high ambient temperature (Shahmohamadi, et al, 2012). situation in Los Angeles City where, for every degree Fahrenheit the temperature rises above 70°F, the incidence of smog increases by 3%. The higher is the temperature, the higher is the formation and concentration of smog The increase in temperature in urban areas could accelerate certain atmospheric chemistry cycles leading to an increase in ground-level ozone [14].
Higher air temperatures can also cause an increase in the emissions Juneof biogenic hydrocarbons as well as higher evaporation rates of synthetic volatile organic compounds (VOCs), both of which are linked to the production of tropospheric ozone.
Luke Howard first proposed the urban heat island concept in 1833, he had examined the average temperature between London city and villages in 1920. As the result showed that the London city temperature is significant higher than the rural area in the day and night due to land usage increasing, lack of vegetation, artificial environments and heat production effect the high temperature in urban area than rural area.
Therefore, UHI change the urban district of the micro-climate, impact of the present as including the reduce insolation, cloud amount increased, rainfall increased, slight increase, and the average wind speed as well as the decrease in air quality degradation, and so on (Landsberg, 1981).
2.2 Causes …show more content…
While the increase in pollution levels leads to more incidences of respiratory illnesses, another impact of the urban heat island on public health.
2.3.2 Thermal comfort
These raised temperatures in city centre derive from the altered thermal balances in urban spaces, mainly due to the materials and activities taking place in cities, by far different to those in rural areas. The increasing numbers of buildings and construction in Ipoh caused that vegetation and trees replaced by buildings. Thus, air temperature increases especially in high density areas (Shahmohamadi, et al, 2012).
Humidity effects—although there is little difference in the amount of water that cities and countrysides retain in their atmospheres (absolute humidity), the higher urban temperatures effectively lowers the relative humidity (since warm air can hold more water than cold air).
2.3.3 …show more content…
The formation of smog that is highly sensitive to temperatures since photochemical reactions are more likely to occur and intensify at higher temperatures. Atmospheric pollution can be aggravated due to the accumulation of smog. In addition, the increased emissions of ozone precursors from vehicles is also associated with the high ambient temperature (Shahmohamadi, et al, 2012). situation in Los Angeles City where, for every degree Fahrenheit the temperature rises above 70°F, the incidence of smog increases by 3%. The higher is the temperature, the higher is the formation and concentration of smog The increase in temperature in urban areas could accelerate certain atmospheric chemistry cycles leading to an increase in ground-level ozone [14].
Higher air temperatures can also cause an increase in the emissions Juneof biogenic hydrocarbons as well as higher evaporation rates of synthetic volatile organic compounds (VOCs), both of which are linked to the production of tropospheric ozone.