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. 2026 Aug 18;23(8):1070.
doi: 10.3390/ijerph23081070.

Effects of Recent Air Pollution Exposure on Children's Neurocognitive Functions and the Possible Link with Endothelial Function

Hanne Hendrickx  1   2 , Annelies Van Eyck  1   3 , Kristien Wouters  4   5 , Julie Degraeve  3 , Kevin Lamote  1 , Roeland Samson  2 , Stijn Verhulst  1   3
Affiliations

Effects of Recent Air Pollution Exposure on Children's Neurocognitive Functions and the Possible Link with Endothelial Function

Hanne Hendrickx et al. Int J Environ Res Public Health. .

Abstract

Air pollution poses a major health risk, particularly in children, who spend considerable time in school. We monitored air pollution in school environments and investigated its impact on cardiovascular and neurocognitive outcomes. Seven elementary schools in Antwerp, Belgium, including one open-air school, participated in a longitudinal study. Indoor and outdoor particulate matter (PM) and outdoor NO2 concentrations were measured. Endothelial function and attentional outcomes were assessed repeatedly (n = 3) in 138 healthy children (mean age of 10.3 ± 0.5 years, 55.8% male). Mixed effect models were used to investigate the association between PM and NO2 exposure and endothelial and attentional outcomes. This study considered median PM concentrations during the 4 h of the study visits (direct exposure), those during the 24 h (acute exposure) and 1 week preceding the study visits (recent exposure), and monthly NO2 concentrations. Models were adjusted for sex, age, BMI-z, and visit. Increased direct (4 h) indoor PM exposure was associated with reduced microvascular dilatation, while selective and sustained attention improved with direct and recent PM exposure, respectively. No associations were found with NO2. Exclusion of the open-air school slightly altered the findings. Larger longitudinal studies with improved exposure assessment are needed to clarify the effects of PM exposure and the influence of (open-air) school environments on children's learning and development.

Keywords: air pollution; endothelial function; neurocognition; pediatrics; schoolchildren.

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Conflict of interest statement

The authors have no conflicts to declare.

Figures

Figure 1
Figure 1
Participating schools. Study area with specific location of the participating schools (blue dots on the left side, S1–S7 on the right). LEZ = Low emission zone. Source background map (left): Grootschalig Referentie Bestand (GRB) Vlaanderen, Digitaal Vlaanderen (Agentschap Digitaal Vlaanderen), reproduced under the Flemish Government Open Data License.
Figure 2
Figure 2
Indoor PM2.5 and outdoor PM1, PM2.5, and PM10 concentrations preceding visits two and three. Percentile boxplots of PM concentrations are shown for each exposure window per school, linked to the second and third visits (black/white boxplots for visit 2 and grey boxplots for visit 3). Whiskers represent P10–P90 range. Participants in school S2 were spread over two days for each visit (S2A and S2B). PM concentrations are expressed in µg/m3.
Figure 3
Figure 3
Monthly average NO2 concentrations across the different schools. School S1–S7 are depicted, of which S1–S4 are city-centered schools and S5 is the open-air school. The exact location of the different schools can be found in Figure 1. Each study visit is indicated as X on the graphs. NO2 = average NO2 concentrations (µg/m3).
Figure 4
Figure 4
Associations between blood pressure parameters and air pollutant concentrations. Linear mixed models were fitted separately for each air pollutant variable and adjusted for visit, age, sex, and BMI z-score. Sys BP = Systolic blood pressure; Dia BP = diastolic blood pressure; PP = pulse pressure. PM2.5 i = indoor PM2.5; PM1 o, PM2.5 o, PM10 o = outdoor PM. Statistical significance is indicated as: *** = p < 0.001, ** = p < 0.01, * = p < 0.05, and · = p < 0.1.
Figure 5
Figure 5
Associations between endothelial function parameters and air pollutant concentrations. Linear mixed models were fitted separately for each air pollutant variable and adjusted for visit, age, sex, BMI-z, and temperature. RHI = Reactive Hyperemic Index; Max RH = maximal dilatation; tpr = time-to-peak response. PM2.5 i = indoor PM2.5; PM1 o, PM2.5 o, PM10 o = outdoor PM. Statistical significance is indicated as: *** = p < 0.001, ** = p < 0.01, * = p < 0.05, and · = p < 0.1.
Figure 6
Figure 6
Associations between neurocognitive function parameters and air pollutant concentrations. Linear mixed models were fitted separately for each air pollutant variable and adjusted for visit, age, sex, and BMI-z. RT = Response time; ACC = accuracy. Stroop task is for selective attention measurement; CPT = continuous performance test for sustained attention measurement. PM2.5 i = indoor PM2.5; PM1 o, PM2.5 o, PM10 o = outdoor PM. Statistical significance is indicated as: *** = p < 0.001, ** = p < 0.01, * = p < 0.05, and · = p < 0.1.
Figure 7
Figure 7
Associations between blood pressure parameters and indoor PM2.5 without open-air school. Analysis was repeated without the open-air school. Linear mixed models were fitted for indoor PM2.5 variables and were adjusted for visit, age, sex, and BMI-z. Sys BP = Systolic blood pressure; Dia BP = diastolic blood pressure; PP = pulse pressure. Statistical significance is indicated as: *** = p < 0.001, ** = p < 0.01, * = p < 0.05, and · = p < 0.1.
Figure 8
Figure 8
Associations between endothelial function parameters and indoor PM2.5 without open-air school. Analysis was repeated without the open-air school. Linear mixed models were fitted for indoor PM2.5 variables and were adjusted for visit, age, sex, BMI-z, and temperature. RHI = Reactive Hyperemic Index; Max RH = maximal dilatation; tpr = time-to-peak response. Statistical significance is indicated as: *** = p < 0.001, ** = p < 0.01, * = p < 0.05, and · = p < 0.1.
Figure 9
Figure 9
Associations between neurocognitive function parameters and indoor PM2.5 without open-air school. Analysis was repeated without the open-air school. Linear mixed models were fitted for indoor PM2.5 variables and were adjusted for visit, age, sex, and BMI-z. RT = Response time; ACC = accuracy. Stroop task is for selective attention measurement; CPT = continuous performance test for sustained attention measurement. Statistical significance is indicated as: *** = p < 0.001, ** = p < 0.01, * = p < 0.05, and · = p < 0.1.
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