The International Energy Agency issued a publication stating that existing buildings are responsible for over 40% of the world total primary energy consumption and 24% of global emissions of carbon dioxide.
To reduce - and ultimately to eliminate - the effects of buildings on the environment and human health, the green building movement was born: it follows a wide range of green building practices and techniques that offer environmental, economic and social benefits.
Green buildings make use of the renewable resources, such as using the sun through solar energy, using plants and trees through green surfaces, and reducing rainwater runoff. Several other techniques are used, such as the use of wood as a building material, or using gravel instead of conventional asphalt or concrete to enhance the groundwater renewal process.
Protecting the environment, outdoor…
The essence of green buildings is the optimization of the site and design efficiency, energy efficiency, water efficiency, and material efficiency, strengthening of the internal environment, maintenance operations optimization, and the reduction of waste and toxic substances.
This philosophy of the building design is that it should be in harmony with the surrounding natural features and resources. There are several key steps in designing sustainable buildings as the selection of the green materials, and the generation of the renewable energy in the site.
… and indoor as well
With regard to enhancing the quality of the indoor environment, the internal environmental quality category in the LEED standards is one of the five categories to provide environmental comfort and luxury for the occupants. The category "internal environmental quality" by LEED standards addresses special design and building guidelines: indoor air quality (IAQ), thermal quality, and the quality of lighting.
IAQ standards seek to reduce volatile organic compounds (VOCs) and other air impurities such as microbial pollutants. Tower buildings depend on a properly designed ventilation system to provide adequate ventilation of clean air by filtering air from the kitchen, laundry, and dry cleaning.
Zero or low VOC emissions
During the process of design and construction, the building materials and the interior finishes are chosen with zero/low VOC emissions to improve indoor air quality. Most building materials, cleaning and maintenance products emit gases, and some are toxic, such as VOCs and formaldehyde. These gases have an adverse effect on the health of users and their comfort. Avoiding these products increases the internal environmental quality in buildings.
It is also important for the IAQ to control the accumulation of moisture that leads to the growth of mold, bacteria, and viruses as well as dust particles and other microbiological organisms. Leaking water through the construction or the condensation of water on cold surfaces on the inside of the building enhance microbial growth. Good insulation helps to solve the problem of moisture, but adequate ventilation is also necessary in order to eliminate the moisture inside which comes from sources as the human metabolic processes, cooking, bathing, cleaning, and other activities.
Integrating daylight and electric light sources
The internal temperature and the control of the air flow in air conditioning systems, coupled with a correct cover of the building also helps to increase the thermal quality of the building.
Creating high-performance luminous environment is done through careful integration of daylight and electric light sources, and improving the quality of lighting and the energy efficiency in the building structure.
Solid wood flooring products, particularly for those with allergies to dust or other particles, are often used so that smooth wood surfaces prevents the accumulation of molecules commonly found in carpets. Medical institutions care for asthma and allergies recommends the use of solid wood and vinyl, tile or linoleum floors instead of carpets. Wood products can be used also in improving air quality through the absorbing or the releasing of moisture in the air for a moderate humidity.
The interaction between all components and occupants forms the processes that determine the quality of the indoor air.