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ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI – FASCICLE II
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ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI
MATHEMATICS, PHYSICS, THEORETICAL MECHANICS
FASCICLE II, YEAR X (XLI) 2018, No. 2
STUDY OF AIR QUALITY IN THE MUSEUM ENVIRONMENT.
GALATI STUDY CASE
Adrian Roșu1, Daniel-Eduard Constantin1, Arseni Maxim1, Mihaela
Timofti1, Mirela Voiculescu1, Bogdan Roșu1, Valentina Calmuc1, Alexandru
Iulian Chelmus2
1"Dunarea de Jos", University of Galati, Faculty of Sciences and Environment, European Center of
Excellence for the Environment, Str. Domneasca, Nr.111, Galati 800008, Romania
2 National Institute of Optoelectronic - INOE 2000, Bucharest, Romania
e-mail address: adrian_rosu_90@yahoo.ro
Abstract
It is known that the conservation of cultural heritage requires that atmospheric parameters as temperature,
humidity or radiation be constant and have well-defined values. Small deviations may irreversibly damage
paintings, sculptures, jewels, textiles, etc. Also, air pollution (i.e. increased concentration of trace gases) may
affect negatively the quality of artworks through direct and indirect corrosion effects. To our knowledge, such
measurements have not been performed in local museums, for a sufficiently long time. This is the first study
where we present measurements of temperature, humidity, and radiation, together with air quality measurements
inside the Visual Art Museum of Galati city (45° 26′ N, 28° 2′ ″ E), Romania. The results will be used in the
future for the implementation of conservation and protection measures of artworks in museums.
Keywords: air pollution, artworks conservation, indoor pollution level, museum, cultural heritage
1. INTRODUCTION
The impact of pollution was first studied to investigate its effect on the human health [1], but
starting with the 90s, the effect of pollutants on the cultural heritage has come to the attention of
conservators and restorers [2]. Nowadays, particular attention is given to the preservation of mobile and
immobile heritage assets. Due to the increase of polluting sources and air quality degradation, the
degradation of artworks is difficult to monitor. [3]. Besides pollution, improper microclimate conditions
of exposition or storage spaces have an important impact on the conservation status of various art works.
Microclimate monitoring, together with studies conducted on the effects of indoor air pollution on
objects, have received an increasing interest over the last decade [4. 5].
Means for identifying risks and evaluating the degradation rate are based on a complex, long-
term monitoring process developed in the areas of interest. Results of such measurements can lead to
relevant decisions and actions to minimize the possible damage caused by temperature, humidity,
pollutants, and light on the objects exhibited in museums. Nowadays, the long-term monitoring is
more accessible and precise, due to the development of intelligent sensorsSuch measurements are
useful for finding the best conservation plan for the multitude of vulnerable organic materials, such as
leather, wood, paper, silk, used to create heritage assets [6].
Temperature and relative humidity variations have the greatest effect on the conservation
status of an object. These may induce stress and sometimes may trigger irreversible changes in the
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physical and chemical properties, with the final result of permanent damaging of the artwork.
However, a constant but inappropriate microclimate may also be just as damaging [7]. The process of
degradation is progressive and cumulative; therefore, on the one hand, museums must, respect
rigorous conditions regarding indoor microclimate [8], and on the other, they must take into account
the atmospheric pollution. The lifetime of pollutants in the air may vary from minutes to days [1].
High traffic and industry development contribute significantly to air pollution in urban areas, due to
the production of particles and gaseous pollutants, such as nitrogen oxides, sulfur dioxide and ozone
[4]. The depositing of atmospheric particles on surfaces of artistic interest can cause an unaesthetic
impact while chemical reactions can damage them [3].
Most museums are historic buildings, whose structural characteristics affect the air exchange
between outside and inside [8]. Also, their historic character sometimes does not allow the
implementation of modern heating and ventilation solutions for the preservation of exposed heritage
objects because these changes could affect the original appearance of the building. Depending on the
possible sources of pollution in the building, in order to protect the artworks, the air inside needs to be
recirculated as much as possible, and the incoming air flux from outside is kept to the minimum [4].
2. METHODS AND DATA
2.1 Site
The main objective of the experimental study was to evaluate the air composition inside the
museum in the period 9 – 11 October 2018, using AEROQUAL monitors. The Museum of Visual Art
(MVA) in Galați city, located at 45° 26′ N, 28° 2′ ″ E (see Fig.1. a), was chosen for the study. One of
the four stations that compose the local NAQMN (National Air Quality Monitoring Network), GL-2 is
located relatively close to the museum (Fig.1. a). This contributed to choosing the museum for our
monitoring campaign since the GL-2 air quality monitoring station can provide information about the
outdoor atmospheric loading. Moreover, MVA is one of the few institutions in Galați city that has
many valuable artwork and heritage objects. Another objective was to study the contribution and the
impact of the air coming inside the museum that is richer in air pollutants because of the heavy road
traffic from one of the main roads that pass by the MVA.
i
Fig.1. a. Location of MVA and GL-2 air quality monitoring stations. b. Locations of AEROQUAL
monitors inside the MVA.
The equipment was based on 3 AEROQUAL compact air monitoring stations (shown in
Fig.2.) that were placed inside the museum, on the ground and the first floors (see Fig.1. b and Fig.2.).
The monitoring stations were placed close to the entrance of each floor. A parallel survey of the
number of people entering and exiting the museum was performed hourly. Data of each atmospheric
b)
Museum of
Visual Art Galați
a)
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parameter recorded by the outdoor air quality monitoring station GL-2 was used in the analysis of the
indoor measurement data.
2.2. Equipment
The characteristics of each sensor that composes the monitoring station are presented in Table
1, together with the corresponding working time.
Table 1 Characteristics of the AEROQUAL sensors used in the monitoring campaign at MVA.
Sensor used
Trace
gas/Parameter
Range
Resolution
Measurement
method
Time interval
Ozone Sensor
O3
0 - 0.5
ppm
0.001 ppm
Gas Sensitive
Semiconductor
(GSS)
10 - 11 Oct. 2018 12 AM – 12 PM
Sulfur Dioxide Sensor
SO2
0 - 10
ppm
0.01 ppm
Gas Sensitive
Semiconductor
(GSS)
9 Oct. 2018 3 PM – 11PM
10 Oct. 2018 12 AM – 11PM
11 Oct. 2018 12 AM – 5 PM
Nitrogen Dioxide
NO2
0 - 1
ppm
0.001 ppm
Gas Sensitive
Semiconductor
(GSS)
9 Oct. 2018 3 PM – 11PM
10 Oct. 2018 12 AM – 11PM
11 Oct. 2018 12 AM – 5 PM
Particulate Matter
Sensor
PM10 and PM2.5
0.001 –
1 ppb
0.001 ppb
Laser particle
counter (LPC)
11 Oct. 201810 AM – 5 PM
Temperature and
Relative Humidity
Sensor
T
RH
40 -
123.8
oC/
0 - 100%
RH
0.01 oC
0.03 % RH
(CMOSens®
technology
(CMOS)
9 Oct. 2018 3 PM – 11PM
10 Oct. 2018 12 AM – 11PM
11 Oct. 2018 12 AM – 5 PM
Fig.2. Installing the AEROQUAL monitors with different sensor type inside the MVA
The electrochemical method is used by the NO2, SO2, O3 sensors as a redox reaction caused
by the effects of electric current, usually through an electrode, in an enclosure called an
electrochemical cell (shown in Fig.3. a). The reaction of the environment with the electrode causes
changes in the state of oxidation that lead to a variation in its resistance to the electrical current, this
variation of resistance leads to a variation in the amount of current, which is proportional to the
LPC sensor
(PM10 and
PM2.5.)
SO2 sensor
NO2 sensor
Temperature and humidity
sensor
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amount of chemical compound with which it has reacted with the electrode. The signal of the
electrode is translated into concentrations through a transducer (processor).
The LPC(Light Particle Counter) sensor (Fig.3. b) used for quantifying PM10 and PM2,5, this
sensor uses a method that is based either on light scattering or light beam obfuscation. A high-
intensity light source is used to illuminate the particle as it passes through the detection chamber. The
particle passes through the light source (usually a laser or halogen light) and if light scattering is used,
the redirected light is detected by a CCD detector. If the light blocking (obturation) is used, the light
loss is detected. The amplitude of the light scattered or blocked by light is measured, and the particles
are counted and sorted into standardized counting sizes.
Fig.3. a. The principle of the electrochemical sensors (adapted after [10]. b. The principle of the LPC
sensors adapted after [11].
The CMOS technology of the temperature and humidity sensor has two modes of operation,
in which either the temperature or the humidity is converted into a digital code representing a
frequency ratio between two oscillators. This ratio is determined by the ratios of the timing
capacitances and bias currents in both oscillators. The reference oscillator is biased by a current
whose temperature dependency is complementary to the proportional absolute temperature (PTAT)
current. For the temperature measurement, this results in an exceptional normalized sensitivity of
about 0.01%/°C at the accepted expense of reduced linearity. The humidity sensor is a capacitor,
whose value varies linearly with relative humidity (RH) with a normalized sensitivity of 0.03%/%
RH.
3. RESULTS AND DISCUSSION
The following air quality parameters were monitored inside the Museum: NO2, SO2, O3,
PM10, PM2.5, Temperature, and Relative Humidity). Additionally, measurements for the same period
from the outdoor monitoring station GL-2 were obtained from [12]. The direct comparison of data
showed no conclusive results so all the data were normalized to the maximum in order to obtain a
more clear picture. Also, the number of people entering and exiting the museum every hour was
considered in order to have some information of air flow from outdoor to indoor. During the
campaign, all concentrations for all monitored atmospheric pollutants were smaller than the legal
limits.
The variation of NO2 and SO2 in Fig.4. show that the concentration of both trace gases
increased indoors after approximately one hour after opened the door of the museum, which allows
the outside air to enter inside the building. Also, the peaks of indoor NO2 follow the outdoor NO2
maxima in most cases, except the afternoon of Oct 10th. This suggests that the reasons for increased
NO2 inside the Museum are indeed the door opening, and not a poor insulation, allowing polluted air
from outside to creep inside. NO2 peaks can be observed around 9 AM, 10 AM and 6 PM, when the
maximum flow of outdoor air occurs during visitors entering and exiting the museum.
The indoor SO2 level to increased exposure to inflowing polluted air from outside is also
clear since the indoor SO2 does not follow strictly the SO2 concentration given by the GL2 station.
b)
a)
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Their outside concentration shows practically no significant peaks, but a relatively constant level.
Thus both NO2 and SO2 in the Museum respond to the incoming flux from outside. A solution to this
would be a two-step entrance.
Fig.4. Variation of NO2 and SO2 indoor (blue, cross, purple, cross) and outdoor GL-2 measurements
(red, plus, blue, asterisk) and the flux of people (green, circle) entering and exiting MVA.
The ozone sensor was used in the period 10 – 11 October at the monitor located at ground
level near the entrance. The sensor is less sensible and the results are not reliable as the sensor
recorded very small concentration of ozone inside the museum during visiting hours only after
approximately one hour when outdoor air entered the museum as a cause of door opening. The ozone
recorded data is presented in Fig.5. A more sensitive technique like chemiluminescence or DOAS is
needed in order to obtain more accurate and conclusive results.
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0
0.2
0.4
0.6
0.8
1
1.2
3 PM
4 PM
5 PM
6 PM
7 PM
8 PM
9 PM
10 PM
11 PM
Number of people
NO2 ppm
Hour
09.10.2018
NO2_outdoor_GL2 (x67.22)
NO2_indoor(x3.04)
Flux of people
SO2_indoor (x0.28)
SO2_outdoor_GL2(x7.18)
0
0.5
1
1.5
2
2.5
0
0.2
0.4
0.6
0.8
1
1.2
12 AM
1 AM
2 AM
3 AM
4 AM
5 AM
6 AM
7 AM
8 AM
9 AM
10 AM
11 AM
12 PM
1 PM
2 PM
3 PM
4 PM
5 PM
6 PM
7 PM
8 PM
9 PM
10 PM
11 PM
Number of people
NO2 ppm
Hour
10.10.2018
NO2_indoor (x2.12)
NO2_outdoor_GL2 (x53.51)
Flux of people
SO2_indoor(x0.32)
SO2_outdoor_GL2(x8.07)
0
1
2
3
4
5
6
7
8
9
10
0
0.2
0.4
0.6
0.8
1
1.2
12 AM
1 AM
2 AM
3 AM
4 AM
5 AM
6 AM
7 AM
8 AM
9 AM
10 AM
11 AM
12 PM
1 PM
2 PM
3 PM
4 PM
5 PM
Number of people
NO2 ppm
Hour
11.10.2018
NO2_indoor(x3.43)
NO2_outdoor_GL2(x94.29)
Flux of people
SO2 _indoor (x1.07)
SO2_outdoor_GL2(x7.18)
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Fig.5. Variation of the indoor (blue, cross) and outdoor (red, plus)O3 and the flux of people (green,
diamond)
Fig.6. Variation of the indoor (blue, cross) and outdoor (red, plus) PM10 concentrations, indoor
PM2.5 (purple, asterisk), and the flux of people (green, diamond). No data was available for GL -2
measured PM2.5
The sensor used for recording of particulate matter was used only on 11 October from 10 AM
to 5 PM. The data is presented in Fig.6, which shows no clear effect on the indoor concentration of
the particulate matter when the outdoor air is entering the museum. The outdoor and indoor trends of
the particulate matter (PM10, PM2.5) are decreasing during measurements.
0
0.5
1
1.5
2
2.5
0
0.2
0.4
0.6
0.8
1
1.2
12 AM
1 AM
2 AM
3 AM
4 AM
5 AM
6 AM
7 AM
8 AM
9 AM
10 AM
11 AM
12 PM
1 PM
2 PM
3 PM
4 PM
5 PM
6 PM
7 PM
8 PM
9 PM
10 PM
11 PM
Number of people
O3 ppm
Hour
10.10.2018
O3_indoor(X0.0001)
O3_outdoor_GL2(x77)
Flux of people
0
1
2
3
4
5
6
7
8
9
10
0
0.2
0.4
0.6
0.8
1
1.2
12 AM
1 AM
2 AM
3 AM
4 AM
5 AM
6 AM
7 AM
8 AM
9 AM
10 AM
11 AM
12 PM
Number of people
O3 ppm
Hour
11.10.2018
O3_indoor(X0.0001)
O3_outdoor_GL2(x77)
Flux of people
0
0.2
0.4
0.6
0.8
1
1.2
0
0.5
1
1.5
2
2.5
10 AM
11 AM
12 PM
1 PM
2 PM
3 PM
4 PM
5 PM
Number of people
PM10\PM2.5 ppm
Hour
11.10.2018
PM10_indoor(x0.04)
PM10_outdoor_GL2(x44.64)
Flux of people
PM2.5_indoor(x0.04)
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Fig.7. Variation of the indoor (blue, cross) and outdoor (red, plus) measurements for Temperature
(left) and Humidity (right) and the flux of people (green, diamond)
Data for temperature and relative humidity are presented in Fig.7. and show that the museum
has a very good air conditioning system. The indoor parameters are constant, despite incoming people
(thus exposure to potential variations). The drop in humidity on Oct 11-that may be associated with a
response to incoming airflow, but this the humidity obviously restored rapidly.
CONCLUSIONS
The results of the experimental study performed in the Visual Art Museum of Galați in the
period 9 – 11 October 2018 showed that the indoor level of NO2 and SO2 may change in response to
the door opening. The other sensors (O3, PM10, PM2.5) measurements are more or less conclusive on
how the airflow from the outside can influence the quality of the air inside the museum. Results on
temperature and relative humidity sensors showed a steady state with no major variation of air inside
the museum. Thus, due to an input of air pollutants (NO2 and SO2) and a relatively high humidity
(more than 40%) indirect influence to the cultural heritage objects can occur by the formation of small
acid particles that can cause damage to wood, leather and pigments [13]. In order to obtain more
information, a more accurate and advanced technique as chemiluminescence (with a higher
measurement resolution and a lower limit of detection) or LP DOAS (Long Path Differential Optical
Absorption Spectroscopy) must be applied [14].
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0.7
0.75
0.8
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
3 PM
4 PM
5 PM
6 PM
7 PM
8 PM
9 PM
10 PM
11 PM
Number of people
Temp (°C)
Hour
09.10.2018
Temp_indoor(°C x24.2)
Temp_outdoor (°C x 22.78)
Flux of people
0
0.5
1
1.5
2
2.5
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
12 AM
2 AM
4 AM
6 AM
8 AM
10 AM
12 PM
2 PM
4 PM
6 PM
8 PM
10 PM
Number of people
Temp (°C)
Hour
10.10.2018
Temp_indoor(°C x23.48)
Temp_outdoor (°C x 17.94)
Flux of people
0
1
2
3
4
5
6
7
8
9
10
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
12 AM
1 AM
2 AM
3 AM
4 AM
5 AM
6 AM
7 AM
8 AM
9 AM
10 AM
11 AM
12 PM
1 PM
2 PM
3 PM
4 PM
5 PM
Number of people
Temp (°C)
Hour
11.10.2018
Temp_indoor(°C x24.2)
Temp_outdoor (°C x 21.88)
Flux of people
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0.7
0.75
0.8
0.85
0.9
0.95
1
1.05
3 PM
4 PM
5 PM
6 PM
7 PM
8 PM
9 PM
10 PM
11 PM
Number of people
RH (%)
Hour
09.10.2018
RH_indoor(% x48.46)
RH_outdoor (% x 76)
Flux of people
0
0.5
1
1.5
2
2.5
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
1.05
12 AM
2 AM
4 AM
6 AM
8 AM
10 AM
12 PM
2 PM
4 PM
6 PM
8 PM
10 PM
Number of people
RH(%)
Hour
10.10.2018
RH_indoor(% x47.15)
RH_outdoor (% x 98)
Flux of people
0
1
2
3
4
5
6
7
8
9
10
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
12 AM
1 AM
2 AM
3 AM
4 AM
5 AM
6 AM
7 AM
8 AM
9 AM
10 AM
11 AM
12 PM
1 PM
2 PM
3 PM
4 PM
5 PM
Number of people
RH (%)
Hour
11.10.2018
RH_indoor(% x46.20)
RH_outdoor (% x 96)
Flux of people
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Acknowledgment
This work was supported by a grant of the Romanian Ministery of Research and Innovation,
CCCDI - UEFISCDI, project number PN-III-P1-1.2-PCCDI-2017-0878/NR. 55PCCDI ⁄ 2018, within
PNCDI III.
References
1. Stefano Paolo Corgnati, Valentina Fabi, Marco Filippi. A methodology for microclimatic
quality evaluation in museums: Application to a temporary exhibit. Building and
Environment, Volume 44, Pages 1253-1260, ISSN 0360-1323, 2009.
2. Hua Li, Tafeng Hu 1, Wenting Jia , Junji Cao, Suixin Liu, Rujin Huang, Tao Ma, Na Xi.
Evaluation of Policy Influence on Long-Term Indoor Air Quality in Emperor Qin’s Terra-
Cotta Museum, China. Atmosphere, Volume 6, Pages 474-489, ISSN 2073-4433, 2016.
3. Anna Worobiec, Lucyna Samek, Agnieszka Krata, Katleen Van Meel, Barbara Krupinska,
Elżbieta Anna Stefaniak, Paweł Karaszkiewicz, René Van Grieken. Transport and deposition
of airborne pollutants in exhibition areas located in historical buildings–study in Wawel
Castle Museum in Cracow, Poland. Journal of Cultural Heritage, Volume 11, Issue 3, Pages
354-359, ISSN 1296-2074, 2010.
4. Paul Lankester and David Thickett. Climate for Collections Standards and Uncertainties
2013. Edited by Jonathan Ashley-Smith, Andreas Burmester and Melanie Eibl, Chapter
Delivering damage functions in enclosures, Doerner Institut London; pp. 339, ISBN: 978-3-
00-042252-2, 2013.
5. Susana Lopez-Aparicio, Terje Grøntoft, Elin Dahlin, Air quality assessment in cultural
heritage institutions using ewo dosimeters, 9th Indoor Air Quality meeting (IAQ) Chalon-sur-
Saône, France, 21-23, ISSN: 1581-9280, April 2010.
6. Elin DAHLIN, Preventive conservation strategies for organic objects in museums, historic
buildings and archives, 5th conference report “cultural heritage research: a Pan European
challenge”. Krakovia. 16-18th de May, 2002.
7. Stefano Paolo Corgnati, Valentina Fabi, Marco Filippi. A methodology for microclimatic
quality evaluation in museums: Application to a temporary exhibit, Building and
Environment, Volume 44, Issue 6, Pages 1253-1260, ISSN 0360-1323, 2009.
8. Joanna Ferdyn-Grygierek. Indoor environment quality in the museum building and its effect
on heating and cooling demand, Energy and Buildings, Volume 85, Pages 32-44, ISSN 0378-
, 2014.
9. Eder, C., Valente, V., Donaldson, N., Demosthenous, A. A cmos smart temperature and
humidity sensor with combined readout. Sensors, 14(9), 17192-17211, 2014.
10. Omar, F. S., Duraisamy, N., Ramesh, K., & Ramesh, S. Conducting polymer and its
composite materials based electrochemical sensor for Nicotinamide Adenine Dinucleotide
(NADH). Biosensors and Bioelectronics, 79, 763-775, 2016.
11. https://en.wikipedia.org/wiki/File:Particlecounter.jpg
12. www.calitateaer.ro (accessed on 12.10.2018)
13. Camuffo, Dario. Microclimate for cultural heritage: conservation, restoration, and
maintenance of indoor and outdoor monuments. Elsevier, 2013.
14. Pttts Jr, J. N., Wallington, T. J., Biermann, H. W., & Winer, A. M. Identification and
measurement of nitrous acid in an indoor environment. Atmospheric Environment
(1967), 19(5), 763-767, 1985.