Year long monitoring of indoor air quality and ventilation in school classrooms in Victoria, Australia

Figures & data

Figure 1. Typical equipment set up in the classroom.

Table 1. Instrument specifications.

Type of instrument	Parameter	Measuring range and accuracy
HOBO MX1102	Air temperature (°C)	±0.21°C from 0° to 50°C
	Relative humidity (%)	±2% from 20% to 80%
	CO2 concentration (ppm)	±50 ppm ±5% of reading at 25°C
Aerocet Handheld Particle Counter Model 531S	PM2.5 PM10	± 10% ± 10%
TSI Dust Trak 8533 Aerosol Monitor	PM2.5 PM10	Particle size range 0.1–15 µm Aerosol concentration range 0.001–150 mg/m^3 Resolution ±0.1% of reading or 0.001 mg/m^3 (whichever is greater)
Testo 480	Air temperature (°C) Relative humidity (%) CO2 concentration (ppm) Globe temperature (°C) Air velocity (ms^−1)	0 to +50°C, ±0.5°C 0 to 100RH%, ±(1.8RH% + 0.7% or measured value) 0 to +10,000, ±(75 ppm CO2 + 3% of measured value) 0 to +120°C, Class 1 0 to +5 ms^−1, ±(0.03 ms^−1–4% of measured value)

Table 2. School classroom characteristics.

School	Classroom	A (m^2)	CH (m)	V (m^3)	Construction	Ventilation
S1	S1A	75.5	2.3–3.3	202.4	Ground floor location; standalone building; metal cladding walls with insulation; perforated metal ceiling; east and west windows; loop pile carpet tile floors	Relocatable classroom, Openable windows – west rear windows are always kept close (windowpanes are covered with student work); east front windows and doors were at times kept open; split air conditioning system; ceiling fans
	S1B	75.5	2.3–3.3	202.4	Ground floor location; standalone building; metal cladding walls with insulation; perforated metal ceiling; east and west windows; loop pile carpet tile floors
S2	S2A	81.0	2.6	210.6	First level location; fibre cement cladding walls; clear single glazed north-east windows with micro-venetian blinds; loop pile carpet tile floors	Openable windows – windows closed in S2A and mostly open in S2B, doors open in S2A and S2B; cassette type (ceiling mounted) split air conditioning – reverse cycle; supplementary floor mounted electric convection heater.
	S2B	81.0	2.6	210.6	First level location; fibre cement cladding walls; clear single glazed north-east windows with micro-venetian blinds; loop pile carpet tile floors
S3	S3A	58.7	3.0	176.2	First level location, brick veneer walls; clear single glazed north windows; loop pile carpet tile floors	Openable windows – windows and doors closed in S3A, windows and door open in S3B; cassette type (ceiling mounted) split air conditioning – reverse cycle; supplementary floor mounted electric convection heater; ceiling fans
	S3B	54.9	3.0	164.7	First level location, brick veneer; clear single glazed south windows; loop pile carpet tile floors
S4	S4A	80.0	2.7	216.0	First level location, brick veneer walls; clear single glazed south windows; loop pile carpet floor finish	Openable windows – windows closed, doors sometimes open to the corridor in S4A and S4B; cassette type (ceiling mounted) split air conditioning – reverse cycle
	S4B	81.3	2.7	219.5	First level location, fibre cement cladding walls; clear single glazed north windows; loop pile carpet floor finish
S5	S5A	61.7	2.9	178.0	Ground floor location; brick veneer walls; no windows; loop pile carpet floor finish	Classrooms not provided with windows, south facing doors are often open to external corridor; cassette type (ceiling mounted) split air conditioning – reverse cycle; ceiling fans
	S5B	63.0	3.10	195.4	Ground floor location; brick veneer walls; no windows; loop pile carpet floor finish

Figure 2. Variations of air temperature in the school classrooms for four school terms during school hours (9:00am–3:30pm).

Figure 3. Variations of relative humidity in the school classrooms for four school terms during school hours (9:00am–3:30pm).

Figure 4. CO₂ concentration levels in the school classrooms for four school terms during school hours (9:00am–3:30pm).

Figure 5. Hourly average CO₂ concentration levels for S3B.

Figure 6. Hourly average CO₂ concentration levels for S4A.

Table 3. Calculated air change rates.

				Air change rates (h^−1)
School	Classroom	V (m^3)	N	T1	T2	T3	T4
S1	S1A	202.4	27	1.48	1.23	1.11	1.32
	S1B	202.4	26	1.44	1.31	1.19	1.26
S2	S2A	210.6	22	1.17	0.86	1.01	1.03
	S2B	210.6	22	2.25	1.71	1.28	1.74
S3	S3A	176.2	15	1.73	1.44	1.32	1.13
	S3B	164.7	26	3.12	2.94	2.85	3.02
S4	S4A	216.0	27	0.83	0.72	0.70	1.03
	S4B	219.5	27	0.88	0.87	0.99	1.14
S5	S5A	178.0	22	2.21	3.02	4.83	2.26
	S5B	195.0	17	1.46	2.37	3.59	1.61

Table 4. Calculated ventilation rate values per student.

			Ventilation rate (Ls^−1 ·p)
School	Classroom	N	T1	T2	T3	T4
S1	S1A	27	3.1	2.6	2.3	2.8
	S1B	26	3.1	2.8	2.6	2.7
	Average		3.1	2.7	2.5	2.8
S2	S2A	22	3.1	2.3	2.7	2.7
	S2B	22	6.0	4.5	3.4	4.6
	Average		4.5	3.4	3.1	3.7
S3	S3A	15	5.6	4.7	4.3	3.7
	S3B	26	5.5	5.2	5.0	5.3
	Average		5.6	4.9	4.7	4.5
S4	S4A	27	1.9	1.6	1.6	2.3
	S4B	27	2.0	1.9	2.2	2.6
	Average		2.0	1.8	1.9	2.5
S5	S5A	22	5.0	6.8	10.9	5.1
	S5B	17	4.6	7.6	11.5	5.1
	Average		4.8	7.2	11.2	5.1

Figure 7. PM₁₀ levels in the schools during four school terms.

Figure 8. PM_2.5 levels in the schools during four school terms.

Figure 9. PM₁₀ indoor–outdoor ratio.

Figure 10. PM_2.5 indoor–outdoor ratio.

Data availability

All data generated or analysed during this study are included in this article (and its supplementary information files).