Indoor air quality and health in schools

We evaluated 1,019 students at 51 elementary schools in the city of Coimbra, Portugal. We applied a questionnaire that included questions regarding the demographic, social, and behavioral characteristics of students, as well as the presence of smoking in the family. We also evaluated the indoor air quality in the schools.

Results:

In the indoor air of the schools evaluated, we identified mean concentrations of carbon dioxide (CO₂) above the maximum reference value, especially during the fall and winter. The CO₂ concentration was sometimes as high as 1,942 ppm, implying a considerable health risk for the children. The most prevalent symptoms and respiratory diseases identified in the children were sneezing, rales, wheezing, rhinitis, and asthma. Other signs and symptoms, such as poor concentration, cough, headache, and irritation of mucous membranes, were identified. Lack of concentration was associated with CO₂ concentrations above the maximum recommended level in indoor air (p = 0.002). There were no other significant associations.

Conclusions:

Most of the schools evaluated presented with reasonable air quality and thermal comfort. However, the concentrations of various pollutants, especially CO₂, suggest the need for corrective interventions, such as reducing air pollutant sources and improving ventilation. There was a statistically significant association between lack of concentration in the children and exposure to high levels of CO₂. The overall low level of pollution in the city of Coimbra might explain the lack of other significant associations.

Air pollution, indoor; Signs and symptoms; respiratory

Pollutants	Sampling period		Δfall/winter – spring/summer (mean)	Maximum reference value according to Portuguese law
Pollutants	Fall/winter	Spring/summer	Δfall/winter – spring/summer (mean)	Maximum reference value according to Portuguese law
CO, ppm	0.42 ± 0.53*	0.14 ± 0.13	0.28	10.7
CO₂, ppm	1578.16* ± 12.49	1152.80 ± 595.41	425.36	984
PM2.5, mg/m³	0.08 ± 0.04	0.10 ± 0.03	−0.02	Not mentioned
PM10, mg/m³	0.12 ± 0.05	0.11 ± 0.03	0.006	0.15
O3, ppm	0.002 ± 0.060	0.0009 ± 0.0040	0.001	0.10
VOCs, ppb	97.82 ± 73.72	90.51 ± 65.66	7.31	260
SO₂, ppm	0.005 ± 0.020	0.004 ± 0.030	0.001	Not mentioned
Formaldehyde, ppm	0.01 ± 0.01*	0.02 ± 0.02	−0.01	0.08

Signs, symptoms, and diseases		School grade						Total
		1st grade			4th grade			Total
		n	% column	% line	n	% column	% line	n	% column
Asthma	No	451	89.3	50.2	448	87.2	49.8	899	88.2
	Yes	54	10.7	45.0	66	12.8	55.0	120	11.8
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Chronic bronchitis	No	495	98.0	49.6	502	97.7	50.4	997	97.8
	Yes	10	2.0	45.5	12	2.3	54.5	22	2.2
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Rales/wheezing	No	420	83.2	48.6	444	86.4	51.4	864	84.8
	Yes	85	16.8	54.8	70	13.6	45.2	155	15.2
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Sneezing attacks	No	382	75.6	50.3	377	73.3	49.7	759	74.5
	Yes	123	24.4	47.3	137	26.7	52.7	260	25.5
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Allergic rhinitis	No	426	84.4	51.0	409	79.6	49.0	835	81.9
	Yes	79	15.6	42.9	105	20.4	57.1	184	18.1
	Total	505	100.0	49.6	514	100.0	50.4	1019	100.0
Breathing difficulties	No	459	90.9	50.1	457	88.9	49.9	916	89.9
	Yes	46	9.1	44.7	57	11.1	55.3	103	10.1
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Stress	No	499	98.8	49.9	502	97.7	50.1	1001	98.2
	Yes	6	1.2	33.3	12	2.3	66.7	18	1.8
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Dizziness	No	497	98.4	49.7	502	97.7	50.3	999	98.0
	Yes	8	1.6	40.0	12	2.3	60.0	20	2.0
	Total	505	100.0	49.6	514	100.0	50.4	1019	100.0
Irritability	No	487	96.4	49.9	489	95.1	50.1	976	95.8
	Yes	18	3.6	41.9	25	4.9	58.1	43	4.2
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Headache	No	472	93.5	50.4	465	90.5	49.6	937	92.0
	Yes	33	6.5	40.2	49	9.5	59.8	82	8.0
	Total	505	100.0	49.6	514	100.0	50.4	1019	100.0
Conjunctival irritation	No	483	95.6	49.8	486	94.6	50.2	969	95.1
	Yes	22	4.4	44.0	28	5.4	56.0	50	4.9
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Insomnia	No	486	96.2	49.7	492	95.7	50.3	978	96.0
	Yes	19	3.8	46.3	22	4.3	53.7	41	4.0
	Total	505	100.0	49.6	514	100.0	50.4	1019	100.0
Cough	No	421	83.4	49.2	434	84.4	50.8	855	83.9
	Yes	84	16.6	51.2	80	15.6	48.8	164	16.1
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0
Lack of concentration	No	402	79.6	50.8	390	75.9	49.2	792	77.7
	Yes	103	20.4	45.4	124	24.1	54.6	227	22.3
	Total	505	100.0	49.6	514	100.0	50.4	1.019	100.0

Respiratory symptoms and diseases	Maximum reference value for carbon dioxide concentration							c2	df	p	OR	95% CI
	Above			Below		Total
	n		%	n	%	n	%
Asthma	Yes	100	11.7	20	12.3	120	11.8	0.046	1	0.831	0.946	0.567-1.579
	No	756	88.3	143	87.7	899	88.2
	Total	856	100.0	163	100.0	1019	100.0
Chronic bronchitis	Yes	18	2.1	4	2.5	22	2.2	0.080	1	0.777	0.854	0.285-2.556
	No	838	97.9	159	97.5	997	97.8
	Total	856	100.0	163	100.0	1019	100.0
Rales/wheezing	Yes	133	15.5	22	13.5	155	15.2	0.442	1	0.506	1.179	0.725-1.917
	No	723	84.5	141	86.5	864	84.8
	Total	856	100.0	163	100.0	1019	100.0
Sneezing attacks	Yes	223	26.1	37	22.7	260	25.5	0.810	1	0.368	1.200	0.807-1.784
	No	633	73.9	126	77.3	759	74.5
	Total	856	100.0	163	100.0	1019	100.0
Allergic rhinitis	Yes	160	18.7	24	14.7	184	18.1	1.457	1	0.227	1.331	0.835-2.122
	No	696	81.3	139	85.3	835	81.9
	Total	856	100.0	163	100.0	1019	100.0
Cough	Yes	141	16.5	23	14.1	164	16.1	0.565	1	0.452	1.200	0.745-1.933
	No	715	83.5	140	85.9	855	83.9
	Total	856	100.0	163	100.0	1019	100.0
Breathing difficulties	Yes	85	9.9	18	11.0	103	10.1	0.187	1	0.666	0.888	0.518-1.522
	No	771	90.1	145	89.0	916	89.9
	Total	856	100.0	163	100.0	1019	100.0

Signs and symptoms	Maximum reference value for carbon dioxide concentration							c2	df	p	OR	95% CI
	Above			Below		Total
	n		%	n	%	n	%
Stress	Yes	14	1.6	4	2.5	18	1.8	0.529	1	0.467	0.661	0.215-2.034
	No	842	98.4	159	97.5	1001	98.2
	Total	856	100.0	163	100.0	1019	100.0
Dizziness	Yes	17	2.0	3	1.8	20	2.0	0.015	1	0.902	1.081	0.313-3.730
	No	839	98.0	160	98.2	999	98.0
	Total	856	100.0	163	100.0	1019	100.0
Irritability	Yes	40	4.7	3	1.8	43	4.2	2.718	1	0.099	2.614	0.799-8.554
	No	816	95.3	160	98.2	976	95.8
	Total	856	100.0	163	100.0	1019	100.0
Headache	Yes	70	8.2	12	7.4	82	8.0	0.123	1	0.726	1.121	0.593-2.118
	No	786	91.8	151	92.6	937	92.0
	Total	856	100.0	163	100.0	1019	100.0
Mucosal irritation	Yes	42	4.9	8	4.9	50	4.9	0.0001	1	0.999	1.000	0.460-2.171
	No	814	95.1	155	95.1	969	95.1
	Total	856	100.0	163	100.0	1019	100.0
Insomnia	Yes	33	3.9	8	4.9	41	4.0	0.393	1	0.531	0.777	0.352-1.714
	No	823	96.1	155	95.1	978	96.0
	Total	856	100.0	163	100.0	1019	100.0
Lack of concentration	Yes	206	24.1	21	12.9	227	22.3	9.888	1	0.002	2.143	1.320-3.478
	No	650	75.9	142	87.1	792	77.7
	Total	856	100.0	163	100.0	1019	100.0

Parents/legal guardians smoking at home	Asthma in children			p	OR	95% CI
Parents/legal guardians smoking at home	Yes	No	TOTAL	p	OR	95% CI
Yes	30 (11.9)	222 (88.1)	252 (100.0)	0.305	1.502	0.687-3.280
No	9 (8.3)	100 (91.7)	109 (100.0)
TOTAL	39 (10.8)	322 (89.2)	361 (100.0)

Sociedade Brasileira de Pneumologia e Tisiologia SCS Quadra 1, Bl. K salas 203/204, 70398-900 - Brasília - DF - Brasil, Fone/Fax: 0800 61 6218 ramal 211, (55 61)3245-1030/6218 ramal 211 - São Paulo - SP - Brazil
E-mail: jbp@sbpt.org.br

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[1] Correspondence to: Ana Maria da Conceição Ferreira Rua 5 de Outubro, São Martinho do Bispo 3000, Coimbra, Portugal Tel. 351 23 980-2430 E-mail: anaferreira@estescoimbra.pt

Brasil

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Indoor air quality and health in schools* * Study carried out at the Coimbra School of Health Technology, Coimbra, Portugal.

Objective:

Methods:

Results:

Conclusions:

Indoor air quality and health in schools^* * Study carried out at the Coimbra School of Health Technology, Coimbra, Portugal.