Hi Farzana, Here's a article that has some useful information related to your question:

http://www.iaqscience.lbl.gov/benefits-summary.html 

Hi Franza, in my opinion, when it comes to hospitals, the most crucial IEQ factor is ventilation strategy.

the proper choice of ventilation strategy not only will provide patients' thermal comfort and assure their well-being, but also it can save their lives!!!

Studies show that patients in controlled environments generally have more rapid physical improvements than do those in uncontrolled environments. proper design for ventilation can provide adequate number of ACH for every kind of patients.. this will allow for sufficient dilution of contaminants inside the space, thus reduce infection transmission. ventilation design also can provide the suitable pressure relationship between different spaces in a way that controls the airflow direction and prevent the infectious particles from migrating to other zones.  

There are four basic factors that moderate the IEQ in buildings. These are Thermal, Acoustical, Lighting and air quality. Maintaining an acceptable level of comfort with the above mentioned four factors would lead to the achievement of good IEQ in buildings and changes in any one of the factors could also lead to changes in the IEQ. 

Environmental Protection Agency (EPA) studies of human exposure to air pollutants indicate that indoor levels of pollutants may be 2 to 5 times, and occasionally more than 100 times, higher than outdoor levels. These levels of indoor air pollutants are of particular concern because it is estimated that most people spend approximately 90 percent of their time indoors. Comparative risk studies performed by the EPA and its Science Advisory Board have consistently ranked indoor air pollution among the top four environmental risks to the public. Being proactive and working to prevent indoor air problems helps to achieve the factors lead to changes in IEQ of a building:

§  Carbon Monoxide (CO) at 9 parts per billion and no greater than 2 parts per million above outdoor levels

§  Naturally ventilated buildings or portions of the buildings must comply with ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality,

§  Prohibit smoking in the building.

§  Design the facility to meet the 2010 FGI Guidelines’ Table 1.2-2 Minimum-Maximum Design Criteria for Noise in representative interior rooms and spaces.

§  Design sound isolation to achieve speech privacy, acoustic comfort and minimal annoyance from noise-producing sources. Consider sound levels at both the source and receiver locations, the background sound at the receiver locations and the occupant’s acoustical privacy and acoustical comfort needs. Speech privacy is defined as “Techniques…to render speech unintelligible to casual listeners’’ by ANSI T1.535-2001, Telecom Glossary 2007.

§  Calculate or measure the room average sound absorption coefficients for representative unoccupied rooms of each type in the building, as necessary, to confirm conformance

§  All adhesives and sealants used on the interior of the building (i.e., inside of the weatherproofing system and applied on-site) must comply with the requirements as applicable to the project scope

§  Paints and coatings used on the interior of the building—defined as inside of the weatherproofing system and applied on-site—shall not exceed the VOC content limits established in South Coast Air Quality Management District (SCAQMD) Rule 1113, Architectural Coatings. (Rules in effect on July 1, 2008.)

§  Develop and implement a hazardous material management program for the construction and pre-occupancy phases of the building.

§  Use lead containment methodologies to prevent release into the air to protect people and prevent soil contamination.

§  Ensure the removal and appropriate disposal of disconnected wires with lead stabilizers.

§  Provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor air intake flow with an accuracy of plus or minus 5% of the design minimum outdoor air rate, as defined by ASHRAE Standard

§  Monitor CO2 concentrations within all naturally ventilated spaces. CO2 monitors must be between 3 and 6 feet (1 and 2 meters) above the floor. One CO2 sensor may be used to monitor multiple non-densely occupied spaces

§  Minimize the entry of contaminants into the building from vehicles, pesticides, herbicides, helipads, diesel generators, designated smoking areas, sources of exhaust air, and other sources of potential contaminant