**6. Materials and methodology of investigation**

The methodology of the study implies the investigation of the levels of indoor air contamina‐ tion with fungi and bacteria. The destination of the investigated indoor spaces was very diverse. The levels of bacteriological contamination were assessed in indoor spaces designated as living spaces, social use spaces like shops, and work and education spaces like schools, offices, and archives.

Quantitative and qualitative assessments were made to evaluate the levels of air contamina‐ tion. Passive and active methods were used to sample the air from the investigated sites. The results were compared to the enforced recommendations in Romania, at this moment.

#### **6.1. Investigated places**

#### *6.1.1. Houses in Bucharest City*

There were 10 investigated apartments, with different numbers of room situated at different floors and with different geographical orientations and different characteristics.

Type of investigated apartments:


For an accurate assessment of the biological contamination of indoor air, the measurements were made three times in a year, in the winter, in the summer, and in the autumn, 3 days consecutively, in the kitchen and in the living room of each investigated apartment.

#### *6.1.2. Schools*

There were two investigated schools, one in Bucharest and one in Giurgiu City.

In the school in Bucharest, the investigations were made


In the school in Giurgiu, investigations were made


*6.1.3. Offices*

Fungi were investigated in eight offices.

#### *6.1.4. Archives*

Fungi were investigated in 10 archive rooms, where the possibility of contamination was presumed.

#### *6.1.5. Shops*

The levels of bacteria in air were investigated (a) in a supermarket in Bucharest City with ground floor and 4 floors and (b) in a shop with only a ground floor.

The investigations were made in the morning when the shop opens and in the evening when the shops were nearly to be closed.

#### **6.2. Sampling methods**

*6.1.2. Schools*

496 Current Air Quality Issues

the school library

**•** in the hall of the school

**•** in a classroom at 8:00 a.m.

**•** in a classroom at 11:00 a.m.

**•** in a classroom at 1:00 p.m.

Fungi were investigated in eight offices.

the shops were nearly to be closed.

**•** in the school hall.

*6.1.3. Offices*

*6.1.4. Archives*

presumed.

*6.1.5. Shops*

There were two investigated schools, one in Bucharest and one in Giurgiu City.

**•** during the school day (at 9.30 a.m.), in a classroom with 23 children

**•** in study room number 1, next to the library with 15 children inside

**•** in study room number 2, next to the library, room that is connected to the hall in front of

Fungi were investigated in 10 archive rooms, where the possibility of contamination was

The levels of bacteria in air were investigated (a) in a supermarket in Bucharest City with

The investigations were made in the morning when the shop opens and in the evening when

ground floor and 4 floors and (b) in a shop with only a ground floor.

**•** in a classroom (at 11:00 a.m.) with 24 children and 1 teacher

**•** in the school library (at 10:00 a.m.) with 3 people inside

**•** in the medical ward, with 8 people inside the room. In the school in Giurgiu, investigations were made

In the school in Bucharest, the investigations were made

**•** in an empty classroom, before 8:00 a.m.

**•** in a classroom with 36 children and 1 teacher

**•** in a classroom with 23 children and 1 teacher

For the bacteriological and fungal evaluation, the sampling methods used were a passive method and an active one [26, 27].

#### *6.2.1. Passive sampling method*

The total number of mesophilic aerobic bacteria, yeast, and molds in the air of selected rooms was determined using the Koch sedimentation method. Bacteria from air were harvested using the gravitational method on the Petri plates with specific growth media. The measurements of levels of bacteria in air were made in several points on each location. The results were expressed as CFU/m3 . The equation used for calculating the results was as follows:

<sup>3</sup> CFU/m = × 10,000/s · /5 *n t*

where n is the number of colonies on the Petri plate, s is the surface of the Petri plate, and *t* is the time of Petri plate exposure. Petri dishes with growth media were exposed for 10 min.

Results obtained by the Koch sedimentation method are less accurate than those from impaction methods with the use of an air sampler. The sedimentation method does not require expensive instrumentation and is cheap and simple. The sedimentation method does not permit exact quantitative determination. Still, this method permit an assessment of the types of microorganisms present in the air and can give an approximation of bacterial and fungal concentration in the air of investigated indoor spaces.

#### *6.2.2. Active sampling method*

This method used an impactor sampler M.A.S.Q.-90, with 2 l/min airflow and a total air volume equal to 200 l.

The following growth media were used [28]:


To obtain the total number of bacteria in the air of investigated rooms, the Petri dishes with growth media were incubated at 37°C for 24 h and then left for another 24 h at room temper‐ ature. To obtain the number of fungi colonies, the Petri dishes were exposed for 10 days at 25°C.

The identification of bacteria types was made by macroscopic estimation (description of colony) and by microscopic estimation.

Diagnosis of filamentous fungi was based on estimation of morphological features of growth on Czapek medium as well as on microscopic observation.

#### **6.3. Indicators used to assessed the air contamination of indoor air**

The following were assessed and counted on a Petri dish:


#### **6.4. References values**

To have a good assessment of the results that were obtained, it was useful to have as references standardized values for the biological contamination of indoor air.

At present, there are no standards or guidelines for microbiological quality of indoor air. Each country has individual regulations and recommendations.

The Commission of the European Communities (CEC) defines the following level of bacterio‐ logical air contamination:0 undetectable, 1-499 CFU/m3 low, 500-999 CFU/m3 medium, >1, 000 CFU/m3 high, and 2, 000 CFU/m3 very high. A value of 10, 000 CFU/m3 of nondescript air‐ borne microbes could therefore be considered a hazardous level for indoor environment [12].

In 2001, the American Industrial Hygiene Association (AIHA) published a proposition of guidelines that stipulate 1, 000 of viable CFU/m3 in air as an upper limit for concentration in indoor environment and for the amount of fungal spores in different indoor environments. It is proposed that the indoor air levels of microorganisms should be less than 500 CFU/m3 for residential buildings and less than 250 CFU/m3 for commercial buildings [29, 30].

According to current Swedish requirements, the number of 500 colony-forming units (CFU) of bacteria and 300 CFU of fungal spores in 1 m3 can be accepted in an indoor environment [31].

The regulation in Brazil stipulates that the upper limit for total amount of airborne microor‐ ganisms (especially fungi) should be 750 CFU/m3 [32, 33].

In Hong Kong, the indoor air levels of microorganism should be less than 1, 000 CFU/m3 of bacteria. The levels are considered excellent if they are less than 500 CFU/m3 [34, 35].

In Taiwan, the indoor air levels of bacteria should not exceeded 500 CFU/m3 and 1, 000 CFU/m3 for fungi [36, 37].

In India, there are no guidelines for the levels of bacteriological contamination of air [38].

In Singapore, the regulation for indoor air quality imposes an upper limit for the concentration of bacteria of 500 CFU/m3 [39].

and 550 CFU/m3

, the minimum value was

for bacteria at 37. The

for

The American Conference of Governmental Industrial Hygienists (ACGIH) stipulates that the counts for total bacteria should not exceed 500 CFU/m3 [40].

WHO (1988) has set a limitation of fungi counts at 500 CFU/m3 [41].

The Korean Indoor Air Quality Control in Public Use Facilities Act prescribes a total airborne bacterial concentration below 800 CFU/m3 for hospitals, nurseries, public nurseries, and hospitals for the elderly and post partum care centers [42, 43]. In Singapore, the regulation for indoor air quality imposes an upper limit for the concentration of bacteria of 500

In Romania, the reference value for indoor air contamination in a house is equal to 2, 500 CFU/ m3 and 550 CFU/m3 for fungi. In schools, the level of bacteriological contamination of air should not exceed 1, 500 CFU/m3 for bacteria at 37°. The presence of coliform bacteria and hemolytic bacteria are not allowed in air inside education units. CFU/m3 [39]. The American Conference of Governmental Industrial Hygienists (ACGIH) stipulates that the counts for total bacteria should not exceed 500 CFU/m 3 [40]. WHO (1988) has set a limitation of fungi counts at 500 CFU/m 3 [41].

for hospitals, nurseries, public nurseries, and hospitals for the elderly and post

The Korean Indoor Air Quality Control in Public Use Facilities Act prescribes a total airborne bacterial

In Romania, the reference value for indoor air contamination in a house is equal to 2,500 CFU/m3

#### **7. Results** partum care centers [42,43].

**6.3. Indicators used to assessed the air contamination of indoor air**

**c.** The presence of *Staphylococcus aureus* and non-*aureus* with and without hemolytic

**d.** The presence of coliform bacteria as an indicator of enteric contamination of air

**f.** The types of fungi as a qualitative assessment of indoor air contamination with fungi

To have a good assessment of the results that were obtained, it was useful to have as references

At present, there are no standards or guidelines for microbiological quality of indoor air. Each

The Commission of the European Communities (CEC) defines the following level of bacterio‐

CFU/m3 high, and 2, 000 CFU/m3 very high. A value of 10, 000 CFU/m3 of nondescript air‐ borne microbes could therefore be considered a hazardous level for indoor environment [12]. In 2001, the American Industrial Hygiene Association (AIHA) published a proposition of guidelines that stipulate 1, 000 of viable CFU/m3 in air as an upper limit for concentration in indoor environment and for the amount of fungal spores in different indoor environments. It is proposed that the indoor air levels of microorganisms should be less than 500 CFU/m3

According to current Swedish requirements, the number of 500 colony-forming units (CFU)

The regulation in Brazil stipulates that the upper limit for total amount of airborne microor‐

In Hong Kong, the indoor air levels of microorganism should be less than 1, 000 CFU/m3 of

In India, there are no guidelines for the levels of bacteriological contamination of air [38].

In Singapore, the regulation for indoor air quality imposes an upper limit for the concentration

bacteria. The levels are considered excellent if they are less than 500 CFU/m3

In Taiwan, the indoor air levels of bacteria should not exceeded 500 CFU/m3

[32, 33].

(colony-forming units/cubic meter,

as quantitative assessment of contami‐

medium, >1, 000

[34, 35].

and 1, 000

for

low, 500-999 CFU/m3

for commercial buildings [29, 30].

can be accepted in an indoor environment [31].

The following were assessed and counted on a Petri dish: **a.** The total number of bacteria, expressed in CFU/m3

**b.** The presence of *Streptococcus* alpha and beta hemolytic

standardized values for the biological contamination of indoor air.

country has individual regulations and recommendations.

logical air contamination:0 undetectable, 1-499 CFU/m3

residential buildings and less than 250 CFU/m3

of bacteria and 300 CFU of fungal spores in 1 m3

ganisms (especially fungi) should be 750 CFU/m3

[39].

for fungi [36, 37].

of bacteria of 500 CFU/m3

**e.** The total number of fungi expressed in CFU/m3

CFU/m3 )

498 Current Air Quality Issues

proprieties

**6.4. References values**

nation

CFU/m3

#### **7.1. Houses in Bucharest City** fungi. In schools, the level of bacteriological contamination of air should not exceed 1,500 CFU/m3 presence of coliform bacteria and hemolytic bacteria are not allowed in air inside education units.

concentration below 800 CFU/m<sup>3</sup>

The highest value for air contamination with germs at 37°C was equal to 21, 466 CFU/m3 in one of the apartments with one room (apartment B). **7. Results 7.1. Houses in Bucharest City** 

In the kitchens, the highest value of contamination identified was equal to 12, 701 CFU/m3 , the minimum value was equal to 201 CFU/m3 , and the highest average value was equal 3, 200 CFU/ m3 (Fig. 1). The highest value for air contamination with germs at 37C was equal to 21,466 CFU/m3 in one of the apartments with one room (apartment B). In the kitchens, the highest value of contamination identified was equal to 12,701 CFU/m3 , the minimum value was equal to 201 CFU/m3 , and the highest average value was equal 3,200 CFU/m3 (Fig. 1).

at 37C).

(Fig. 2).

In the living rooms, the highest identified value of contamination was equal to 21,466 CFU/m3 equal to 210 CFU/m3 , and the highest average value was equal 4,731 CFU/m3 **Figure 1.** Bacteriological contamination of kitchen air (CFU/m3 at 37°C).

Fig. 1. Bacteriological contamination of kitchen air (CFU/m<sup>3</sup>

CFU/m3

**7. Results** 

room (apartment B).

to 201 CFU/m3

[39].

bacteria should not exceed 500 CFU/m

concentration below 800 CFU/m3

**7.1. Houses in Bucharest City** 

partum care centers [42,43].

In the living rooms, the highest identified value of contamination was equal to 21, 466 CFU/m3 , the minimum value was equal to 210 CFU/m3 , and the highest average value was equal 4, 731 CFU/m3 (Fig. 2). Fig. 1. Bacteriological contamination of kitchen air (CFU/m3 at 37C). In the living rooms, the highest identified value of contamination was equal to 21,466 CFU/m3 , the minimum value was equal to 210 CFU/m3 , and the highest average value was equal 4,731 CFU/m3 (Fig. 2).

In Singapore, the regulation for indoor air quality imposes an upper limit for the concentration of bacteria of 500

The American Conference of Governmental Industrial Hygienists (ACGIH) stipulates that the counts for total

The Korean Indoor Air Quality Control in Public Use Facilities Act prescribes a total airborne bacterial

In Romania, the reference value for indoor air contamination in a house is equal to 2,500 CFU/m3

fungi. In schools, the level of bacteriological contamination of air should not exceed 1,500 CFU/m3

presence of coliform bacteria and hemolytic bacteria are not allowed in air inside education units.

The highest value for air contamination with germs at 37C was equal to 21,466 CFU/m3

In the kitchens, the highest value of contamination identified was equal to 12,701 CFU/m3

, and the highest average value was equal 3,200 CFU/m3

3 [41].

for hospitals, nurseries, public nurseries, and hospitals for the elderly and post

(Fig. 1).

and 550 CFU/m3

in one of the apartments with one

, the minimum value was equal

for bacteria at 37. The

for

3 [40].

WHO (1988) has set a limitation of fungi counts at 500 CFU/m

**Figure 2.** Levels of bacteriological air contamination in living rooms (CFU/m3 at 37°C).

Taking into account the moment of the day, the highest bacteriological contamination (average values) was found in the living room, in the evening, and was equal to 6, 665 CFU/m3 in the one room apartment—apartment B (Fig. 3).

at 37C).

in one room

Summer kitchen Summer living room Fall kitchen Fall living room Winter kitchen Winter living room

Fig. 3. Average numbers of germs at 37C in the morning and in the evening in investigated apartments. The indoor air contamination is higher in the fall and in the winter, reaching a level equal to 7,853 CFU/m3 **Figure 3.** Average numbers of germs at 37°C in the morning and in the evening in investigated apartments.

Fig. 4. Average numbers of germs at 37C according to the season in investigated apartments.

In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

apartment—apartment B (Fig. 4).

contamination of air (Fig. 5).

The indoor air contamination is higher in the fall and in the winter, reaching a level equal to 7, 853 CFU/m3 in one room apartment (average values)—apartment B (Fig. 4).

In the living rooms, the highest identified value of contamination was equal to 21, 466

Taking into account the moment of the day, the highest bacteriological contamination (average values) was found in the living room, in the evening, and was equal to 6, 665 CFU/m3

Fig. 3. Average numbers of germs at 37C in the morning and in the evening in investigated apartments. The indoor air contamination is higher in the fall and in the winter, reaching a level equal to 7,853 CFU/m3

**Figure 3.** Average numbers of germs at 37°C in the morning and in the evening in investigated apartments.

Fig. 4. Average numbers of germs at 37C according to the season in investigated apartments.

In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

at 37C).

In Singapore, the regulation for indoor air quality imposes an upper limit for the concentration of bacteria of 500

The American Conference of Governmental Industrial Hygienists (ACGIH) stipulates that the counts for total

The Korean Indoor Air Quality Control in Public Use Facilities Act prescribes a total airborne bacterial

In Romania, the reference value for indoor air contamination in a house is equal to 2,500 CFU/m3

fungi. In schools, the level of bacteriological contamination of air should not exceed 1,500 CFU/m3

presence of coliform bacteria and hemolytic bacteria are not allowed in air inside education units.

The highest value for air contamination with germs at 37C was equal to 21,466 CFU/m3

In the kitchens, the highest value of contamination identified was equal to 12,701 CFU/m3

, and the highest average value was equal 3,200 CFU/m3

3 [41].

for hospitals, nurseries, public nurseries, and hospitals for the elderly and post

(Fig. 1).

(Fig. 2).

at 37C).

at 37°C).

3 [40].

WHO (1988) has set a limitation of fungi counts at 500 CFU/m

, and the highest average value was

, the minimum value was

Minimum values Maximum values Average values

in the

in one room

Summer kitchen Summer living room Fall kitchen Fall living room Winter kitchen Winter living room

Morning ‐ kitchen Morning ‐ living rooms Evening Kitchen Evening ‐ living rooms

in one of the apartments with one

, the minimum value was equal

and 550 CFU/m3

for bacteria at 37. The

for

, the minimum value was equal to 210 CFU/m3

Fig. 2. Levels of bacteriological air contamination in living rooms (CFU/m3

**Figure 2.** Levels of bacteriological air contamination in living rooms (CFU/m3

one room apartment—apartment B (Fig. 3).

apartment—apartment B (Fig. 4).

contamination of air (Fig. 5).

In the living rooms, the highest identified value of contamination was equal to 21,466 CFU/m3

, and the highest average value was equal 4,731 CFU/m3

Fig. 1. Bacteriological contamination of kitchen air (CFU/m3

(Fig. 2).

CFU/m3

500 Current Air Quality Issues

equal 4, 731 CFU/m3

equal to 210 CFU/m3

0

5000

10000

15000

20000

25000

CFU/m3

**7. Results** 

room (apartment B).

to 201 CFU/m3

[39].

bacteria should not exceed 500 CFU/m

concentration below 800 CFU/m3

**7.1. Houses in Bucharest City** 

partum care centers [42,43].

In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological **Figure 4.** Average numbers of germs at 37°C according to the season in investigated apartments.

contamination of air (Fig. 5).

contamination of air (Fig. 5).

3500

Fig. 4. Average numbers of germs at 37C according to the season in investigated apartments.

4000 In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological contamination of air (Fig. 5). Fig. 4. Average numbers of germs at 37C according to the season in investigated apartments.

In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

2‐Room Apartment with linked

2‐Room Apartment with linked

2‐Room Apartment with linked

2‐Room Apartment with separate rooms C

rooms E

rooms F

rooms D

In connection to the type of apartment, bacteriological contamination is higher in the apartments with two linked rooms. **Figure 5.** Number of germs at 37°C in houses according to the smoking habit.

Fig. 5. Number of germs at 37C in houses according to the smoking habit.

Bacteriological contamination is also presented in the three-room apartment (Figs. 6 and 7).

Fig. 6. Number of germs at 37C and the type of apartment (apartments with two rooms).

Kitchen Living Room

In connection to the type of apartment, bacteriological contamination is higher in the apart‐ ments with two linked rooms. Bacteriological contamination is also presented in the threeroom apartment (Figs. 6 and 7). Fig. 5. Number of germs at 37C in houses according to the smoking habit. In connection to the type of apartment, bacteriological contamination is higher in the apartments with two linked rooms.

In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

Fig. 4. Average numbers of germs at 37C according to the season in investigated apartments.

Bacteriological contamination is also presented in the three-room apartment (Figs. 6 and 7).

**Figure 6.** Number of germs at 37°C and the type of apartment (apartments with two rooms).

Fig. 6. Number of germs at 37C and the type of apartment (apartments with two rooms).

Fig. 6. Number of germs at 37C and the type of apartment (apartments with two rooms).

Contamination of air with staphylococci reached the highest value equal to 7,988 CFU/m3 in the kitchen and 10,157 **Figure 7.** Number of germs at 37°C and the type of apartment (apartments with three rooms).

in the living room (Figs. 8 and 9).

CFU/m3

Fig. 7. Number of germs at 37C and the type of apartment (apartments with three rooms).

Contamination of air with staphylococci reached the highest value equal to 7, 988 CFU/m3 in the kitchen and 10, 157 CFU/m3 in the living room (Figs. 8 and 9).

).

Fig. 4. Average numbers of germs at 37C according to the season in investigated apartments.

Fig. 5. Number of germs at 37C in houses according to the smoking habit.

Bacteriological contamination is also presented in the three-room apartment (Figs. 6 and 7).

Fig. 6. Number of germs at 37C and the type of apartment (apartments with two rooms).

contamination of air (Fig. 5).

CFU/m3

in the living room (Figs. 8 and 9).

In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

In connection to the type of apartment, bacteriological contamination is higher in the apartments with two linked rooms.

**Figure 8.** Contamination with staphylococci in kitchen air (CFU/m3 ).

Fig. 8. Contamination with staphylococci in kitchen air (CFU/m3

In connection to the type of apartment, bacteriological contamination is higher in the apart‐ ments with two linked rooms. Bacteriological contamination is also presented in the three-

In connection to the type of apartment, bacteriological contamination is higher in the apartments with two linked rooms.

In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

In connection to the type of apartment, bacteriological contamination is higher in the apartments with two linked rooms.

2‐Room Apartment with linked

2‐Room Apartment with linked

2‐Room Apartment with linked

3‐Room Apartment with linked

3‐Room Apartment with linked

3‐Room Apartment with linked

3‐Room Apartment with separate rooms G

rooms I

rooms J

rooms H

in the kitchen and 10,157

in

2‐Room Apartment with separate rooms C

rooms E

rooms F

rooms D

In connection to the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

Fig. 4. Average numbers of germs at 37C according to the season in investigated apartments.

Fig. 5. Number of germs at 37C in houses according to the smoking habit.

Bacteriological contamination is also presented in the three-room apartment (Figs. 6 and 7).

Fig. 4. Average numbers of germs at 37C according to the season in investigated apartments.

Fig. 6. Number of germs at 37C and the type of apartment (apartments with two rooms).

Fig. 6. Number of germs at 37C and the type of apartment (apartments with two rooms).

Fig. 7. Number of germs at 37C and the type of apartment (apartments with three rooms). Contamination of air with staphylococci reached the highest value equal to 7,988 CFU/m3

Contamination of air with staphylococci reached the highest value equal to 7, 988 CFU/m3

in the living room (Figs. 8 and 9).

**Figure 7.** Number of germs at 37°C and the type of apartment (apartments with three rooms).

Kitchen Living Room

Bacteriological contamination is also presented in the three-room apartment (Figs. 6 and 7).

**Figure 6.** Number of germs at 37°C and the type of apartment (apartments with two rooms).

Kitchen Living Room

Fig. 5. Number of germs at 37C in houses according to the smoking habit.

room apartment (Figs. 6 and 7).

contamination of air (Fig. 5).

CFU/m3

the kitchen and 10, 157 CFU/m3

0

500

1000

1500

2000

2500

3000

in the living room (Figs. 8 and 9).

contamination of air (Fig. 5).

502 Current Air Quality Issues

The ratio between staphylococci/germs at 37C is around 40% in the kitchen and over 50% in the living rooms (Fig. 10). **Figure 9.** Contamination with staphylococci in living rooms air (CFU/m).

Fig. 9. Contamination with staphylococci in living rooms air (CFU/m).

Fig. 10. Ratio between staphylococci/germs at 37 in investigated houses.

*niger*, *Rhizopus*, *Mucor*, *Cladosporium herbarum*, and *Fusarium*.

children and 1 teacher, the value identified was 140 CFU/m3

measured were 2,802 CFU/m3

0 10

and 10,859 CFU/m3

7.2. Schools

CFU/m3

was 25 CFU/m3

The ratio between staphylococci/germs at 37°C is around 40% in the kitchen and over 50% in the living rooms (Fig. 10).

20 30 40 50 60 The assessment of the fungal contamination showed that in many homes, the level of fungal contamination was very high in all investigated rooms. The levels of fungi were between 635 and 10, 859 CFU/m3 . The highest values measured were 2, 802 CFU/m3 in the living room, 2,

The assessment of the fungal contamination showed that in many homes, the level of fungal contamination was

% in the kitchen % in the living room

In a school in Bucharest, the following results were obtained: in an empty classroom, before 8:00 a.m., the value identified

in the kitchen, 7,675 CFU/m3

; in a classroom (at 11:00 a.m.) with 24 children and 1 teacher,

in the bedroom (highest overall). The species of fungi identified were *Penicillium*, *Aspergillus* 

; during the school day (at 9.30:00 a.m.) in a classroom with 23 children, the value identified was 67

. The highest values

in the bathroom,

% in the kitchen % in the living room

; in a classroom with 23

very high in all investigated rooms. The levels of fungi were between 635 and 10,859 CFU/m3

in the living room, 2,302 CFU/m3

; in a classroom with 36 children and 1 teacher, the value identified was 229 CFU/m3

**Figure 10.** Ratio between staphylococci/germs at 37° in investigated houses.

Fig. 10. Ratio between staphylococci/germs at 37 in investigated houses.

302 CFU/m3 in the kitchen, 7, 675 CFU/m3 in the bathroom, and 10, 859 CFU/m3 in the bedroom (highest overall). The species of fungi identified were *Penicillium*, *Aspergillus niger*, *Rhizopus*, *Mucor*, *Cladosporium herbarum*, and *Fusarium*. very high in all investigated rooms. The levels of fungi were between 635 and 10,859 CFU/m3 . The highest values measured were 2,802 CFU/m3 in the living room, 2,302 CFU/m3 in the kitchen, 7,675 CFU/m3 in the bathroom, and 10,859 CFU/m3 in the bedroom (highest overall). The species of fungi identified were *Penicillium*, *Aspergillus niger*, *Rhizopus*, *Mucor*, *Cladosporium herbarum*, and *Fusarium*.

; during the school day (at 9.30:00 a.m.) in a classroom with 23 children, the value identified was 67

The assessment of the fungal contamination showed that in many homes, the level of fungal contamination was

#### **7.2. Schools** 7.2. Schools In a school in Bucharest, the following results were obtained: in an empty classroom, before 8:00 a.m., the value identified was 25 CFU/m3

In a school in Bucharest, the following results were obtained: in an empty classroom, before 8:00 a.m., the value identified was 25 CFU/m3 ; during the school day (at 9.30:00 a.m.) in a classroom with 23 children, the value identified was 67 CFU/m3 ; in a classroom with 36 children and 1 teacher, the value identified was 229 CFU/m3 ; in a classroom with 23 children and 1 teacher, the value identified was 140 CFU/m3 ; in a classroom (at 11:00 a.m.) with 24 children and 1 teacher, the value identified was 1, 465 CFU/m3 with 38 CFU/m3 *Streptococcus* alphahemolytic present; in the school library (at 10:00 a.m.) with 3 people inside, the biological contamination of air was equal to 45 CFU/m3 ; in study room number 1, next to the library with 15 children inside, the level of air contamination was equal to 89 CFU/m3 ; in study room number 2, next to the library, the room connected to the hall in front of the school library, the level of biological air contamination was equal to 427 CFU/m3 ; the level of air contamination in the school hall was equal to 180 CFU/m3 ; in the medical ward, with 8 people inside the room, the level of biological air contamination was equal to 60 CFU/m3 , 1 CFU/m3 *Streptococcus* alpha hemolytic, and 1 CFU/m3 *Streptococcus* beta hemolytic present (Fig.11). CFU/m3 ; in a classroom with 36 children and 1 teacher, the value identified was 229 CFU/m3 ; in a classroom with 23 children and 1 teacher, the value identified was 140 CFU/m3 ; in a classroom (at 11:00 a.m.) with 24 children and 1 teacher, the value identified was 1,465 CFU/m3 with 38 CFU/m3 *Streptococcus* alpha-hemolytic present; in the school library (at 10:00 a.m.) with 3 people inside, the biological contamination of air was equal to 45 CFU/m3 ; in study room number 1, next to the library with 15 children inside, the level of air contamination was equal to 89 CFU/m3 ; in study room number 2, next to the library, the room connected to the hall in front of the school library, the level of biological air contamination was equal to 427 CFU/m3 ; the level of air contamination in the school hall was equal to 180 CFU/m3 ; in the medical ward, with 8 people inside the room, the level of biological air contamination was equal to 60 CFU/m3 , 1 CFU/m3 *Streptococcus* alpha hemolytic, and 1 CFU/m3 *Streptococcus* beta hemolytic present (Fig.11).

In a school in Giurgiu City, the following results were obtained: at 8:00 a.m., a number of 1, 259 CFU/m3 was identified; at 11:00 a.m., a number of 1, 732 CFU/m3 was identified; at 1:00 p.m., a level of biological air contamination equal to 472 CFU/m3 was identified. In the school hall, the level of air contamination was equal to 2, 202 CFU/m3 , the level of contamination of the air with *S.* non-*aureus* was equal to 1, 259 CFU/m3 at 8:00 a.m. and 11:00 a.m., and 472 CFU/ m3 at 1:00 p.m.; the level of contamination with *Streptococcus* alpha-hemolytic was equal to 157

; in a classroom with 23

; in study room number 1,

was identified; at

, 1 CFU/m3 *Streptococcus* alpha

; in a classroom (at 11:00 a.m.) with 24 children and 1 teacher,

with 38 CFU/m3 *Streptococcus* alpha-hemolytic present; in the school library (at

In a school in Bucharest, the following results were obtained: in an empty classroom, before 8:00 a.m., the value identified

; in a classroom with 36 children and 1 teacher, the value identified was 229 CFU/m3

10:00 a.m.) with 3 people inside, the biological contamination of air was equal to 45 CFU/m3

8 people inside the room, the level of biological air contamination was equal to 60 CFU/m3

hemolytic, and 1 CFU/m3 *Streptococcus* beta hemolytic present (Fig.11).

; during the school day (at 9.30:00 a.m.) in a classroom with 23 children, the value identified was 67

In a school in Giurgiu City, the following results were obtained: at 8:00 a.m., a number of 1,259 CFU/m3 **Figure 11.** Level of bacteriological contamination of air in a school in Bucharest City.

Fig. 11. Level of bacteriological contamination of air in a school in Bucharest City.

Fig. 11. Level of bacteriological contamination of air in a school in Bucharest City.

can be dangerous for children health (Fig.12).

11:00 a.m., a number of 1,732 CFU/m3

7.2. Schools

CFU/m3

was 25 CFU/m3

equal to 427 CFU/m3

children and 1 teacher, the value identified was 140 CFU/m3

the value identified was 1,465 CFU/m3

CFU/m3 at 11:00 a.m. In a classroom and in the school hall, at 1:00 p.m., coliform bacteria were identified as an indicator of enteric contamination of air. The level of contamination with coliform bacteria was equal to 315 CFU/m3 . The detected levels of coliform bacteria can be dangerous for children health (Fig.12). In a school in Giurgiu City, the following results were obtained: at 8:00 a.m., a number of 1,259 CFU/m3 was identified; at 11:00 a.m., a number of 1,732 CFU/m3 was identified; at 1:00 p.m., a level of biological air contamination equal to 472 CFU/m3 was identified. In the school hall, the level of air contamination was equal to 2,202 CFU/m3 , the level of contamination of the air with *S.* non-*aureus* was equal to 1,259 CFU/m3 at 8:00 a.m. and 11:00 a.m., and 472 CFU/m3 at 1:00 p.m.; the level of contamination with *Streptococcus* alpha-hemolytic was equal to 157 CFU/m3 at 11:00 a.m. In a classroom and in the school hall, at 1:00 p.m., coliform bacteria were identified as an indicator of enteric contamination of air. The level of contamination with coliform bacteria was equal to 315 CFU/m3 . The detected levels of coliform bacteria CFU/m3 was identified. In the school hall, the level of air contamination was equal to 2,202 CFU/m3 , the level of contamination of the air with *S.* non-*aureus* was equal to 1,259 CFU/m3 at 8:00 a.m. and 11:00 a.m., and 472 CFU/m3 at 1:00 p.m.; the level of contamination with *Streptococcus* alpha-hemolytic was equal to 157 CFU/m3 at 11:00 a.m. In a classroom and in the school hall, at 1:00 p.m., coliform bacteria were identified as an indicator of enteric contamination of air. The level of contamination with coliform bacteria was equal to 315 CFU/m3 . The detected levels of coliform bacteria can be dangerous for children health (Fig.12).

was identified; at 1:00 p.m., a level of biological air contamination equal to 472

**7.3. Offices**  The levels of fungal contamination were between 734 and 4,034 CFU/m3 . The fungi species identified were *Penicillium* spp., *A. niger*, *A. flavus*, *Aspergillus versicolor*, *Mucor*, and *Cladosporium*. **Figure 12.** Levels of bacteriological air contamination in a school in Giurgiu City.

pollution with fungi, the following types of fungi were identified: *Penicillium* spp., *A. niger*, *A. flavus*, *A.* 

Fig. 12. Levels of bacteriological air contamination in a school in Giurgiu City.

#### **7.4. Archives**  The levels of fungal contamination were between 655 and 1,490 CFU/m3 **7.3. Offices**

302 CFU/m3

**7.2. Schools**

259 CFU/m3

m3

in the kitchen, 7, 675 CFU/m3

*niger*, *Rhizopus*, *Mucor*, *Cladosporium herbarum*, and *Fusarium*.

**Figure 10.** Ratio between staphylococci/germs at 37° in investigated houses.

*Mucor*, *Cladosporium herbarum*, and *Fusarium*.

measured were 2,802 CFU/m3

504 Current Air Quality Issues

and 10,859 CFU/m3

7.2. Schools

CFU/m3

was 25 CFU/m3

equal to 427 CFU/m3

8:00 a.m., the value identified was 25 CFU/m3

the value identified was 1,465 CFU/m3

teacher, the value identified was 140 CFU/m3

contamination of air was equal to 45 CFU/m3

in the school hall was equal to 180 CFU/m3

and 1 teacher, the value identified was 229 CFU/m3

children and 1 teacher, the value identified was 140 CFU/m3

and 1 teacher, the value identified was 1, 465 CFU/m3

classroom with 23 children, the value identified was 67 CFU/m3

hemolytic, and 1 CFU/m3 *Streptococcus* beta hemolytic present (Fig.11).

Fig. 10. Ratio between staphylococci/germs at 37 in investigated houses.

level of biological air contamination was equal to 427 CFU/m3

the level of biological air contamination was equal to 60 CFU/m3

hall, the level of air contamination was equal to 2, 202 CFU/m3

the air with *S.* non-*aureus* was equal to 1, 259 CFU/m3

hemolytic, and 1 CFU/m3 *Streptococcus* beta hemolytic present (Fig.11).

(highest overall). The species of fungi identified were *Penicillium*, *Aspergillus niger*, *Rhizopus*,

in the bedroom (highest overall). The species of fungi identified were *Penicillium*, *Aspergillus* 

; during the school day (at 9.30:00 a.m.) in a classroom with 23 children, the value identified was 67

The assessment of the fungal contamination showed that in many homes, the level of fungal contamination was

% in the kitchen % in the living room

very high in all investigated rooms. The levels of fungi were between 635 and 10,859 CFU/m3

in the living room, 2,302 CFU/m3

; in a classroom with 36 children and 1 teacher, the value identified was 229 CFU/m3

In a school in Bucharest, the following results were obtained: in an empty classroom, before

In a school in Bucharest, the following results were obtained: in an empty classroom, before 8:00 a.m., the value identified

hemolytic present; in the school library (at 10:00 a.m.) with 3 people inside, the biological

next to the library, the room connected to the hall in front of the school library, the level of biological air contamination was

; the level of air contamination in the school hall was equal to 180 CFU/m3

number 2, next to the library, the room connected to the hall in front of the school library, the

In a school in Giurgiu City, the following results were obtained: at 8:00 a.m., a number of 1,

p.m., a level of biological air contamination equal to 472 CFU/m3 was identified. In the school

at 1:00 p.m.; the level of contamination with *Streptococcus* alpha-hemolytic was equal to 157

was identified; at 11:00 a.m., a number of 1, 732 CFU/m3 was identified; at 1:00

15 children inside, the level of air contamination was equal to 89 CFU/m3

10:00 a.m.) with 3 people inside, the biological contamination of air was equal to 45 CFU/m3

next to the library with 15 children inside, the level of air contamination was equal to 89 CFU/m3

8 people inside the room, the level of biological air contamination was equal to 60 CFU/m3

in the bathroom, and 10, 859 CFU/m3 in the bedroom

in the kitchen, 7,675 CFU/m3

with 38 CFU/m3 *Streptococcus* alpha-hemolytic present; in the school library (at

; during the school day (at 9.30:00 a.m.) in a

; in a classroom (at 11:00 a.m.) with 24 children and 1 teacher,

; in a classroom (at 11:00 a.m.) with 24 children

; in study room number 1, next to the library with

; in the medical ward, with 8 people inside the room,

; in a classroom with 23 children and 1

with 38 CFU/m3 *Streptococcus* alpha-

, 1 CFU/m3 *Streptococcus* alpha

; in a classroom with 36 children

; in study room number 2,

; in the medical ward, with

; in study room number 1,

; in a classroom with 23

. The highest values

in the bathroom,

% in the kitchen % in the living room

; the level of air contamination

, 1 CFU/m3 *Streptococcus* alpha

, the level of contamination of

at 8:00 a.m. and 11:00 a.m., and 472 CFU/

; in study room

*versicolor*, *Mucor*, *Cladosporium*. The levels of fungal contamination were between 734 and 4, 034 CFU/m3 . The fungi species identified were *Penicillium* spp., *A. niger*, *A. flavus*, *Aspergillus versicolor*, *Mucor*, and *Cladospo‐ rium*.

. By a qualitative assessment of air

#### **7.4. Archives**

The levels of fungal contamination were between 655 and 1, 490 CFU/m3 . By a qualitative assessment of air pollution with fungi, the following types of fungi were identified: *Penicilli‐ um* spp., *A. niger*, *A. flavus*, *A. versicolor*, *Mucor*, *Cladosporium*.

#### **7.5. Shops**

In a supermarket with ground floor and 4 floors, the levels of bacteriological contamination are shown in Table 1.


**Table 1.** Levels of bacteriological air contamination in a supermarket in Bucharest City (M = morning, E = evening)

The highest levels of contamination were registered in the evening and were equal to 13, 836 bacteria at 37°/m3 air at the ground floor and 13, 509 bacteria at 37°/m3 air at the third floor. In the second and fourth floors, in the evening, the level of bacteria in air were equal to 10, 917 bacteria at 37°/m3 air and 10, 352 bacteria at 37°/m3 air. In the first floor, in the evening, levels of bacterial contamination equal to 9, 259 bacteria at 37°/m3 air were registered. The levels of air contamination were the lowest in the first floor (Fig. 13).

floor <sup>M</sup> 6,155.45 4,276.33 299.75 226.25 182.5 0 <sup>E</sup>10,916.75 8,705.5 339 286.25 549.16 0

floor <sup>M</sup> 6,946 4,914.25 280.25 141 273.5 0 <sup>E</sup>13,509.25 10,800.5 419.5 316 775.5 0

The highest levels of contamination were registered in the evening and were equal to 13,836 bacteria at 37/m3 air at the ground floor and 13**,**509 bacteria at 37/m<sup>3</sup> air at the third floor. In the second and fourth floors, in the Fig. 13. Levels of bacteriological contamination of air in a supermarket—average values. The highest levels of contamination were registered in the evening and were equal to 13,836 bacteria at 37/m3 at the ground floor and 13**,**509 bacteria at 37/m<sup>3</sup> air at the third floor. In the second and fourth floors, in the **Figure 13.** Levels of bacteriological contamination of air in a supermarket—average values.

the first floor, in the evening, levels of bacterial contamination equal to 9,259 bacteria at 37/m3 air were

 air—average values. The contamination of air, in the case of the supermarket with a ground floor and other four floors, with staphylococci was high in the evening. The highest levels were registered in the third floor with a contamination

the first floor, in the evening, levels of bacterial contamination equal to 9,259 bacteria at 37/m3

registered. The levels of air contamination were the lowest in the first floor (Fig. 13).

registered. The levels of air contamination were the lowest in the first floor (Fig. 13).

evening, the level of bacteria in air were equal to 10,917 bacteria at 37/m3

Fig. 13. Levels of bacteriological contamination of air in a supermarket—average values.

evening, the level of bacteria in air were equal to 10,917 bacteria at 37/m3

**7.4. Archives**

506 Current Air Quality Issues

**7.5. Shops**

**Average values**

Ground floor

Second floor

Fourth floor

bacteria at 37°/m3

are shown in Table 1.

**Total number of bacteria at 37°/m3 air**

The levels of fungal contamination were between 655 and 1, 490 CFU/m3

*um* spp., *A. niger*, *A. flavus*, *A. versicolor*, *Mucor*, *Cladosporium*.

**Total number of staphylococci/m3 air**

assessment of air pollution with fungi, the following types of fungi were identified: *Penicilli‐*

In a supermarket with ground floor and 4 floors, the levels of bacteriological contamination

**Hemolytic staphylococci/m3 air**

M 5, 140.75 3, 296 161.25 197.72 328.75 3.24

E 13, 836.00 10, 397.25 404.5 240.75 964.25 0

E 9, 258.75 7, 316 372 232.5 569.33 0

M 6, 155.45 4, 276.33 299.75 226.25 182.5 0

E 10, 916.75 8, 705.5 339 286.25 549.16 0

E 13, 509.25 10, 800.5 419.5 316 775.5 0

M 6, 473.75 4, 292.75 301.25 189.97 228 0

E 10, 352.25 7, 759.75 405.25 267.78 560 0

**Table 1.** Levels of bacteriological air contamination in a supermarket in Bucharest City (M = morning, E = evening)

air and 10, 352 bacteria at 37°/m3

air contamination were the lowest in the first floor (Fig. 13).

The highest levels of contamination were registered in the evening and were equal to 13, 836 bacteria at 37°/m3 air at the ground floor and 13, 509 bacteria at 37°/m3 air at the third floor. In the second and fourth floors, in the evening, the level of bacteria in air were equal to 10, 917

of bacterial contamination equal to 9, 259 bacteria at 37°/m3 air were registered. The levels of

First floor M 3, 919.25 2, 015.5 137.5 170.55 213.66 0

Third floorM 6, 946 4, 914.25 280.25 141 273.5 0

*Staphylococcus aureus/m3*

 *air*

**α Hemolytic streptococci/m3 air**

air. In the first floor, in the evening, levels

. By a qualitative

**β Hemolytic streptococci/m3 air**

air and 10,352 bacteria at 37/m3

air were

air and 10,352 bacteria at 37/m3

air. In

air

air. In

air, the

air, and the first floor

burden equal to 10,801 bacteria at 37/m3 air, followed by the ground floor with 10,397 bacteria at 37/m<sup>3</sup> second floor with 8,706 bacteria at 37/m3 air, the fourth floor with 7,760 bacteria at 37/m3 **Figure 14.** Total number of staphylococci/m3 air—average values.

Fig. 14.Total number of staphylococci/m3

with 7,316 bacteria at 37/m3

Second

Third

Fourth

floor (Fig.14). Hemolytic staphylococci/m3 air and *S. aureus*/m<sup>3</sup> air were identified in the same amount in the evening at al floors. α Hemolytic streptococci/m3 air were identified in the highest levels in the evening at the ground floor. In the evening, at the other floors, the levels were almost equal. β Hemolytic streptococci/m3 air were identified at the ground floor only. In a shop with only a ground floor, the levels of bacteriological contamination are presented in Table 2. Table 2. Levels of bacteriological air contamination in a shop with only a ground floor in Bucharest City (M = morning, E = evening) The contamination of air, in the case of the supermarket with a ground floor and other four floors, with staphylococci was high in the evening. The highest levels were registered in the third floor with a contamination burden equal to 10, 801/m3 air, followed by the ground floor with 10, 397/m3 air, the second floor with 8, 706/m3 air, the fourth floor with 7, 760/m3 air, and the first floor with 7, 316/m3 air. It can be seen that the levels of air contamination were the lowest in the first floor (Fig.14).

air. It can be seen that the levels of air contamination were the lowest in the first

Hemolytic staphylococci/m3 air and *S. aureus*/m3 air were identified in the same amount in the evening at al floors.

α Hemolytic streptococci/m3 air were identified in the highest levels in the evening at the ground floor. In the evening, at the other floors, the levels were almost equal.

β Hemolytic streptococci/m<sup>3</sup> air were identified at the ground floor only.

In a shop with only a ground floor, the levels of bacteriological contamination are presented in Table 2.


**Table 2.** Levels of bacteriological air contamination in a shop with only a ground floor in Bucharest City (M = morning, E = evening)

Fig. 15. Levels of bacteriological contamination of air in shop with only a ground floor. In the shop with only a ground floor, the levels of air contamination registered higher values in the evening than in the morning measurements for mesophilic bacteria, total number of staphylococci, hemolytic staphylococci, *S.* **Figure 15.** Levels of bacteriological contamination of air in shop with only a ground floor.

contaminations were higher in the fall and winter, especially in the one room apartment—apartment B.

in the living room with average values between 2,406 and 7,903 CFU/m3

The highest levels of staphylococci in air were, in the summer, between 26,125 CFU/m3

in the kitchen and 55,000 CFU/m3

Another study performed in Torun University in Poland [45] had the following results: The levels of air contamination with bacteria were between 7 and 3,313 CFU/m3

. The air pollution with fungi ranged between 0 and 893 CFU/m3

in the bathroom with average values between 4,308 CFU/m3

*aureus*, and α hemolytic streptococci (Fig.15). **8. Discussions** In the investigated houses, the highest value for air contamination with germs, at 37C, was found in one of the apartments with one room (apartment B). Regarding the time of the day, the highest level of bacteriological contamination was found In the shop with only a ground floor, the levels of air contamination registered higher values in the evening than in the morning measurements for mesophilic bacteria, total number of staphylococci, hemolytic staphylococci, *S. aureus*, and α hemolytic streptococci (Fig.15).

in the evening, in the one room apartment—apartment B. Taking into account the time of the year, the indoor air

Considering the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

The air pollution with fungi was visualized as a layer on the Petri dish in the kitchen and bathroom, and in the living room

in the afternoon. The outdoor fungal background ranged between 217 and 3,750 CFU/m3

Another study that investigated the levels of biological contamination of indoor air in eight libraries of the Jimma

#### contamination of air where there were smokers present. Considering the type of the apartments, in apartments with more than one room, bacteriological contamination is at the **8. Discussions**

and 6,300 CFU/m3

and 6,421 CFU/m3

were between 10,250 CFU/m3

.

CFU/m3

study.

highest level in the apartment with two linked rooms.

the maximum level registered was equal to 1,820 CFU/m3

between 53 and 5,673 CFU/m3

air ranged from 10 to 310 CFU/m3

University in Addis Ababa [46] had the following results:

The levels of bacteria were between 367 and 2,595 CFU/m3

The levels of fungi were between 524 and 1,992 CFU/m3

The ratio between staphylococci/germs at 37C is around 40% in the kitchen and over 50% in the living rooms. In a previous study [44], the levels of bacteriological and fungal pollution of indoor air were as follows: In summer, the maximum levels of bacteria were equal to 57,500 CFU/m3 in the kitchen and bathroom and 32,500 CFU/m3 in the living room with average values between 6,090 and 13,241 CFU/m3 . In winter, the maximum levels of bacteria were equal to 12,600 CFU/m3 in the kitchen, 50,400 CFU/m3 In the investigated houses, the highest value for air contamination with germs, at 37°C, was found in one of the apartments with one room (apartment B). Regarding the time of the day,

and 7,200 CFU/m3

air at different sample site. The amount of bacteria found in the outdoor

in the bathroom,

in the living room and 55,000

. In winter, the maximum values

as the background and

.

.

.

in the morning and 0 and 1,373 CFU/m<sup>3</sup>

with an average value equal to 1,476. CFU/m3

with an average value equal to 1,087 CFU/m3

.

. The fungi species identified were the same like in the present

in the bathroom, with the average values between 3,219

the highest level of bacteriological contamination was found in the evening, in the one room apartment—apartment B. Taking into account the time of the year, the indoor air contamina‐ tions were higher in the fall and winter, especially in the one room apartment—apartment B.

α Hemolytic streptococci/m3

β Hemolytic streptococci/m<sup>3</sup>

**Total number of bacteria at 37°/m3 air**

in Table 2.

508 Current Air Quality Issues

**Average values**

Ground floor

E = evening)

air were identified in the highest levels in the evening at the

*Staphylococcus aureus/m3*

 *air*

3108

in the kitchen and bathroom and 32,500

in the bathroom,

in the living room and 55,000

. In winter, the maximum values

as the background and

.

.

.

in the morning and 0 and 1,373 CFU/m3

with an average value equal to 1,476. CFU/m3

with an average value equal to 1,087 CFU/m3

.

and 7,200 CFU/m3

air at different sample site. The amount of bacteria found in the outdoor

in the kitchen, 50,400 CFU/m3

.

. The fungi species identified were the same like in the present

in the bathroom, with the average values between 3,219

**α Hemolytic streptococci/m3**

**air**

**β Hemolytic streptococci/m3**

**air**

air were identified at the ground floor only.

**Hemolytic staphylococci/m3**

**air**

M 2, 398.16 1, 323.2 78 47.3 86.5 0 E 3, 107.5 2, 217.85 90.08 164.76 75.65 0

**Table 2.** Levels of bacteriological air contamination in a shop with only a ground floor in Bucharest City (M = morning,

**Levels of mesophilic bacteria/m3 air average values** Levels of mesophilic bacteria ‐ average values

In a shop with only a ground floor, the levels of bacteriological contamination are presented

ground floor. In the evening, at the other floors, the levels were almost equal.

**air**

**Total number of staphylococci/m3**

Fig. 15. Levels of bacteriological contamination of air in shop with only a ground floor.

**Figure 15.** Levels of bacteriological contamination of air in shop with only a ground floor.

2398

contaminations were higher in the fall and winter, especially in the one room apartment—apartment B.

The ratio between staphylococci/germs at 37C is around 40% in the kitchen and over 50% in the living rooms. In a previous study [44], the levels of bacteriological and fungal pollution of indoor air were as follows:

in the living room with average values between 2,406 and 7,903 CFU/m3

*aureus*, and α hemolytic streptococci (Fig.15).

contamination of air where there were smokers present.

highest level in the apartment with two linked rooms.

the maximum level registered was equal to 1,820 CFU/m3

between 53 and 5,673 CFU/m3

air ranged from 10 to 310 CFU/m3

University in Addis Ababa [46] had the following results:

The levels of bacteria were between 367 and 2,595 CFU/m3

The levels of fungi were between 524 and 1,992 CFU/m3

In summer, the maximum levels of bacteria were equal to 57,500 CFU/m3

in the bathroom with average values between 4,308 CFU/m3

In winter, the maximum levels of bacteria were equal to 12,600 CFU/m3

in the living room with average values between 6,090 and 13,241 CFU/m3

The highest levels of staphylococci in air were, in the summer, between 26,125 CFU/m3

in the kitchen and 55,000 CFU/m3

Another study performed in Torun University in Poland [45] had the following results: The levels of air contamination with bacteria were between 7 and 3,313 CFU/m3

. The air pollution with fungi ranged between 0 and 893 CFU/m3

**8. Discussions**

CFU/m3

**8. Discussions**

CFU/m3

study.

and 6,300 CFU/m3

and 6,421 CFU/m3

were between 10,250 CFU/m3

.

In the shop with only a ground floor, the levels of air contamination registered higher values in the evening than in the morning measurements for mesophilic bacteria, total number of staphylococci, hemolytic staphylococci, *S.*

Morning Evening

In the shop with only a ground floor, the levels of air contamination registered higher values in the evening than in the morning measurements for mesophilic bacteria, total number of staphylococci, hemolytic staphylococci, *S. aureus*, and α hemolytic streptococci (Fig.15).

In the investigated houses, the highest value for air contamination with germs, at 37°C, was found in one of the apartments with one room (apartment B). Regarding the time of the day,

In the investigated houses, the highest value for air contamination with germs, at 37C, was found in one of the apartments with one room (apartment B). Regarding the time of the day, the highest level of bacteriological contamination was found in the evening, in the one room apartment—apartment B. Taking into account the time of the year, the indoor air

Considering the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological

Considering the type of the apartments, in apartments with more than one room, bacteriological contamination is at the

The air pollution with fungi was visualized as a layer on the Petri dish in the kitchen and bathroom, and in the living room

in the afternoon. The outdoor fungal background ranged between 217 and 3,750 CFU/m3

Another study that investigated the levels of biological contamination of indoor air in eight libraries of the Jimma

Considering the smoking habit of the inhabitants, apartments with one and two rooms had a higher bacteriological contamination of air where there were smokers present.

Considering the type of the apartments, in apartments with more than one room, bacteriolog‐ ical contamination is at the highest level in the apartment with two linked rooms.

The ratio between staphylococci/germs at 37°C is around 40% in the kitchen and over 50% in the living rooms.

In a previous study [44], the levels of bacteriological and fungal pollution of indoor air were as follows:

In summer, the maximum levels of bacteria were equal to 57, 500 CFU/m3 in the kitchen and bathroom and 32, 500 CFU/m3 in the living room with average values between 6, 090 and 13, 241 CFU/m3 .

In winter, the maximum levels of bacteria were equal to 12, 600 CFU/m3 in the kitchen, 50, 400 CFU/m3 in the bathroom, and 6, 300 CFU/m3 in the living room with average values between 2, 406 and 7, 903 CFU/m3 .

The highest levels of staphylococci in air were, in the summer, between 26, 125 CFU/m3 in the living room and 55, 000 CFU/m3 in the bathroom with average values between 4, 308 CFU/m3 and 7, 200 CFU/m3 . In winter, the maximum values were between 10, 250 CFU/m3 in the kitchen and 55, 000 CFU/m3 in the bathroom, with the average values between 3, 219 and 6, 421 CFU/m3 .

The air pollution with fungi was visualized as a layer on the Petri dish in the kitchen and bathroom, and in the living room the maximum level registered was equal to 1, 820 CFU/m3 . The fungi species identified were the same like in the present study.

Another study performed in Torun University in Poland [45] had the following results:


Another study that investigated the levels of biological contamination of indoor air in eight libraries of the Jimma University in Addis Ababa [46] had the following results:


The microbiological quality of air in the investigated rooms in the Bucharest school as well as in the Giurgiu school changed significantly during the school day. The highest levels were found around 11:00 a.m. in classrooms with large numbers of persons inside. Most of the levels identified in the study were under the limit of 1, 000 CFU/m3 , with the exceptions of one measurement in the school in Bucharest and four measurements in the school in Giurgiu City. Also, the presence of *Streptococcus* beta hemolytic and coliform bacteria in classrooms air represents a threat to the health of children. This threat appears to be greater in the school in Giurgiu City.

The fungi levels identified in offices and archives were over the limit accepted in Romania. Isolated fungi species include *Cladosporium*, *A. flavus*, *A. niger*, and *Penicillium* sp.

In the case of the shop with only a ground floor and the supermarket, it is obvious that the size of the shop, the numbers of floors, and the numbers of departments in the shop can induce a high bacteriological contamination of air due to the high number of people visiting the shops. The air contamination in the supermarket was found to be higher at the ground floor and at the third and fourth floors. The high level of bacteriological contamination at the ground floor is probably due to the large number of visitors, while at the third and fourth floor it is probably due to the accumulation of bacteria coming from the first and second floors. In the shop with only a ground floor, the levels of air contamination in the evening were lower than in the morning. It is probable that this type of shop has better ventilation. High levels of staphylococci and the presence of *Streptococcus* in air can be dangerous for human health, and it is necessary to have a very strong disinfection action.

## **9. Conclusions**

From this study, several conclusions can be drawn:

