The temperature, relative humidity, noise, carbon dioxide, and particulate matter (PM 10 ) in a public library in Sao Carlos, SP, Brazil, were monitored between May and September 2013. The building is naturally ventilated through tilted windows and doors. The PM 10 concentrations in August and September were the highest when rainfall was at levels near zero. Over the entire study period, the temperature and relative hum idity values were acceptable, but most users consider the library to be hot on hot days and cold on cold days. The CO 2 and noise levels were below the recommended standard, but the users and employees of the library frequently complain about the noise levels.
There is strong evidence that poor environmental quality compromises our health, comfort and well-being and has various destructive effects on our bodies. Whether at work, at leisure or at home, people are often exposed to pollutant levels that are well above those considered acceptable for preserving health [
The World Health Organization (WHO) considers indoor air pollution to be a major environmental and public health problem, especially for people in developing countries [
According to Pope [
Noise pollution also exerts a negative influence on human health, according to the WHO. Excessive noise can cause hearing damage, interfere with communication, disturb sleep, cause cardiovascular and physiological damage, reduce intellectual performance and cause changes in social behavior. Hearing damage is often related to work environments and increased urban noise.
According to Willich et al. [
Persily and Dols [
In this study, we consider the importance of IAQ in public libraries. Libraries frequently contain a large num- ber of people sitting in place for a long time, accumulate a great deal of paper (books, magazines and newspapers), and are situated in unsatisfactory locations in the city. The PM10, CO2, noise, temperature and relative humidity were simultaneously measured inside and outside in São Carlos’ Public Library. The goal was to verify the indoor air quality for people that use the local and the importance of the pollutants levels in their health.
The “Amadeu Amaral” Public Library is located in downtown São Carlos, SP, Brazil (22˚S, 48˚W), on the corner of two streets with intense vehicular and foot traffic. This location has high noise levels, which renders the library an inappropriate place for reading and studying. The library has nine employees, and approximately 100 people use the library daily. The library consists of three levels (
The temperature, relative humidity, noise, carbon dioxide level and airborne particle concentration (PM10) were measured on each floor and outdoors. These parameters were monitored from May to September 2013. In each week of the sampling period, measurements were randomly taken on three normal workdays (08:00 to 17:00). The indoor sampling instruments were placed on supports 1.5 m above the ground, in the center of the room. The outdoor sampling sites were located between the library and the busiest street.
The temperature and relative humidity were measured every 15 minutes using a digital thermo hygrometer (HygroPalm-0, Rotronic Instrument Corp., New York, USA). CO2 levels were measured using a continuous multigas monitor with a range of 0 to 5000 ppm (MultiRAE IR PGM-54, Rae Systems Inc., California, USA). Noise was measured using alogging sound meter with a range of 30 to 130 dB (DEC-490, Instrutherm, São Paulo, Brazil). A dust monitor (Aerocet 531, Met One Instruments, Inc., Oregon, USA) was used to measure the PM10.
The monthly average temperature and relative humidity values during the study period are shown in
The monthly average internal and external temperatures on the three levels were not significantly different. The standard deviation of the outdoor temperature was approximately 3˚C, and the standard deviation of the indoor temperature was approximately 2˚C. These deviations show that the building has little influence on the temperature. The relative humidity inside and outside the building were also very similar, which seems to be characteristic of buildings utilizing natural ventilation.
These results enabled us to evaluate the thermal comfort of the library’s visitors. Thermal comfort is defined as satisfaction with the thermal environment. The factors that influence the thermal comfort levels of the library’s
Period | Floor 1 | Floor 2 | Floor 3 | Floor 4 | ||||
---|---|---|---|---|---|---|---|---|
Period average (˚C) | Standard deviation (˚C) | Period average (˚C) | Standard deviation (˚C) | Period average (˚C) | Standard deviation (˚C) | Period average (˚C) | Standard deviation (˚C) | |
May | 22.4 | 2.6 | 22.5 | 2.9 | 22.5 | 2.7 | 21.6 | 3.8 |
June | 21.3 | 1.8 | 21.6 | 2.1 | 21.4 | 2.0 | 21.1 | 3.1 |
July | 23.2 | 1.4 | 23.9 | 1.5 | 23.8 | 1.5 | 23.9 | 2.8 |
August | 23.2 | 2.7 | 23.9 | 2.9 | 23.9 | 2.8 | 24.2 | 4.0 |
September | 25.6 | 1.9 | 26.3 | 1.8 | 26.3 | 1.8 | 26.8 | 2.2 |
Period | Floor 1 | Floor 2 | Floor 3 | Floor 4 | ||||
---|---|---|---|---|---|---|---|---|
Period average (%) | Standard deviation (%) | Period average (%) | Standard deviation (%) | Period average (%) | Standard deviation (%) | Period average (%) | Standard deviation (%) | |
May | 55.0 | 5.4 | 54.3 | 5.1 | 54.3 | 5.7 | 57.5 | 7.2 |
June | 53.7 | 7.8 | 51.8 | 8.3 | 52.5 | 7.6 | 53.5 | 12.2 |
July | 53.7 | 13.0 | 51.0 | 12.6 | 51.4 | 12.6 | 51.0 | 18.0 |
August | 39.5 | 11.5 | 37.1 | 11.6 | 37.7 | 11.5 | 36.3 | 15.4 |
September | 42.3 | 7.8 | 40.4 | 7.7 | 40.4 | 7.7 | 38.5 | 7.0 |
occupants can be divided into environmental (temperature, thermal radiation, humidity, airspeed) and personal factors (personal activity and condition, clothing).
The literature on thermal comfort usually focuses on humidity and temperature and their influence on personal well-being. One approach to defining a comfort zone and setting appropriate limits is using the standards defined in the ISO 7730-1994 [
Outside the comfort zone, May and June had the lowest temperatures, with daily averages of approximately 18˚C. August had the lowest average daily relative humidity (approximately 20%) and a high average daily temperature (above 27˚C). Approximately 62% of the data lie within the comfort zone.
The monthly average noise levels are calculated in the same manner as the temperature and relative humidity averages and are shown in
According to Willich et al. [
Period | Floor 1 | Floor 2 | Floor 3 | Floor 4 | ||||
---|---|---|---|---|---|---|---|---|
Period average (dBA) | Standard deviation (dBA) | Period average (dBA) | Standard deviation (dBA) | Period average (dBA) | Standard deviation (dBA) | Period average (dBA) | Standard deviation (dBA) | |
May | 61.5 | 3.4 | 58.9 | 3.4 | 58.2 | 4.1 | 68.5 | 5.6 |
June | 60.8 | 3.7 | 59.3 | 3.8 | 58.9 | 3.8 | 68.0 | 5.7 |
July | 61.3 | 4.3 | 59.5 | 3.5 | 58.4 | 4.1 | 68.6 | 5.9 |
August | 63.0 | 4.3 | 61.0 | 3.3 | 58.1 | 3.7 | 68.1 | 6.2 |
September | 63.0 | 4.5 | 60.8 | 3.5 | 58.8 | 3.9 | 67.8 | 6.1 |
hearing damage but not from cardiovascular risks. Noise is a frequent burden in daily life, particularly in metropolitan areas and work sites.
Other studies have observed the harmful effects caused by exposure to high noise levels, demonstrating the need for proper standards to preserve public health [
The average PM10 concentrations during the study period are shown in
The indoor PM10 data exhibited similar behavior, with the highest averages in the driest months, most noticeably on the first and second floors. However, the activities performed within the environment also influence the PM10 concentration. Manipulating objects (books, magazines and newspapers), displacing people and cleaning activities can all generate and resuspend particulate matter and contribute to an increased internal PM10 concentration (i.e., the internal PM10 concentration depends on both the external environment and the internal activities).
The equipment (Hi-Vol) used by Bruno et al. [
The WHO updated its Air Quality Guidelines in 2005 [
The monthly average particulate matter concentrations (PM10) obtained in this study were calculated from measurements taken over 8 hours. The indoor PM10 was usually below the 50 μg/m3 value recommended by the WHO.
The monthly average CO2 concentrations in the library are shown in
Period | Floor 1 | Floor 2 | Floor 3 | Floor 4 | ||||
---|---|---|---|---|---|---|---|---|
Period average (µg/m3) | Standard deviation (µg/m3) | Period average (µg/m3) | Standard deviation (µg/m3) | Period average (µg/m3) | Standard deviation (µg/m3) | Period average (µg/m3) | Standard deviation (µg/m3) | |
May | 25.9 | 10.0 | 30.6 | 15.2 | 20.2 | 8.2 | 24.4 | 5.3 |
June | 20.8 | 5.6 | 25.0 | 5.6 | 25.0 | 5.6 | 25.0 | 5.6 |
July | 26.5 | 7.2 | 29.0 | 8.4 | 30.3 | 8.4 | 23.3 | 8.4 |
August | 51.9 | 10.5 | 35.0 | 12.0 | 19.8 | 7.0 | 43.7 | 6.4 |
September | 46.7 | 17.5 | 46.7 | 12.0 | 18.5 | 4.5 | 53.7 | 4.5 |
The mean daily peak CO2 concentration was 600 ppm, with a standard deviation of 30 ppm. ASHRAE Standard 62.1-2010 [
In a building with constant occupancy, the daily maximum CO2 concentration is related to the building's air exchange rate. The relationship between the CO2 concentration and the air exchange rate was extensively discussed by Persily and Dols [
To understand people’s opinions regarding the air quality of the library, eighteen people (nine users and nine employees) were interviewed. Each interviewee was asked the following two questions: What do you think about the thermal comfort of the library? What symptoms have you experienced because of the air quality of the library?
The answers provided by respondents are summarized in
According to Witterseh et al. [
Temperature and humidity have a strong and significant impact on the perception of indoor air quality; at a constant pollution level, the perceived air quality decreases with increasing air temperature and humidity [
Over the specific period of the study, the library exhibited low indoor levels of PM10 and CO2 and acceptable ranges of temperature and humidity. In the warmer months of the year (between November and March), the site is considered to be too hot. The noise levels are below standard values but may be considered to be high for a location that people visit to read and study.
The “Amadeu Amaral” Public Library has never been located in a building designed specifically to be a library. The library has changed locations many times and has always been located in a space inappropriate for the needs of a library. Currently, the library is located in an adapted building that was originally designed to be a museum. The library is located in the downtown area, which is easy for the public to access. However, the excessive noise level caused by the vehicular traffic surrounding this location is disturbing.
Assessing the Indoor Air Quality (IAQ) of a place that many people frequent daily contributes to the understanding of the most frequent complaints of its occupants. Investigating these complaints often includes air sampling, which must be carefully conducted if representative data are to be collected. From the information obtained from these measurements, actions to improve local conditions can be taken.
According to Jones [
The authors are grateful to FAPESP and CNPq for their support for this research. The authors especially thank the staff and administration of the “Amadeu Amaral” Public Library, who made this study possible.
Guilherme C. do Nascimento,Wiclef D. Marra Júnior,Fernanda S. Peiter, (2016) Indoor Environmental Quality in a Public Library in Sao Carlos, SP, Brazil. Open Access Library Journal,03,1-9. doi: 10.4236/oalib.1102685