Vegetation and vehicle emissions around primary schools across urban Australia: associations with academic performance.

BACKGROUND: Evolving evidence suggests that vegetation surrounding schools is beneficial to children's academic performance, however vehicle emissions are adversely related. Little is known about concurrent impacts of vegetation and vehicle emissions on academic performance. This study examined associations of vegetation and vehicle emissions near urban Australian primary schools with children's academic performance. METHODS: Vegetation within schoolyards and Euclidean buffers (100, 300 and 1000 m) was assessed using the Normalized Difference Vegetation Index (NDVI). Weighted road density (WRD) was computed for each buffer as a vehicle emissions proxy. Cross-sectional associations and mediating pathways between vegetation and vehicle emissions and standardized average academic scores in Literacy (Reading, Writing, Language Conventions) and Mathematics for Grades 3 and 5 attending 3745 primary schools in urban areas (population ≥10,000) of Australia in 2018 were assessed using generalised linear models adjusted for school socio-educational status. RESULTS: Significant positive associations were found between vegetation and Reading in Grades 3 and 5, Mathematics in Grade 3 (all buffers), Writing in Grade 3 (100 and 300 m), and Language Conventions in Grades 3 and 5 (most buffers). Increased vehicle emissions were negatively associated with Reading and Mathematics in Grades 3 and 5 (most buffers), and Language Conventions in Grade 3 (300 and 1000 m) and Grade 5 (100-1000 m). Within 300 m, vehicle emissions partially mediated associations between vegetation with Mathematics in Grade 3 (proportion mediated, 21%), Reading and Language Conventions in Grade 5 (15%, 37% respectively). CONCLUSIONS: Our findings contribute to growing evidence that vegetation around primary schools is associated with higher achievement in Literacy and Mathematics, with partial mediation by vehicle emissions. Future studies should conduct on-site measurement of vehicle emissions and audit vegetation around schools to confirm findings and inform urban/school planners and school leaders on designing and modifying school environments to support learning.

Associations of traffic-related air pollution and greenery with academic outcomes among primary schoolchildren.

BACKGROUND: There is preliminary evidence that greenery/greenspace around schools may be positively associated with children's cognitive development and academic outcomes, whereas traffic-related air pollution (TRAP) may have a detrimental effect. Few studies have examined pathways between both exposures and academic outcomes. This study aimed to assess associations between greenery, road traffic density (a proxy for TRAP) surrounding primary (elementary) schools, and academic achievement of primary schoolchildren in Melbourne, Australia. METHODS: This cross-sectional study examined mean academic scores in Years 3 and 5 for primary schools (n = 851) in Greater Melbourne. Scores were from the 2018 'National Assessment Program - Literacy and Numeracy' (NAPLAN) in five domains: 'Reading'; 'Writing'; 'Spelling'; 'Grammar & Punctuation' and 'Numeracy'. Greenery was measured within school boundaries and surrounding Euclidean buffers (100, 300, 1000 and 2000 m) using the Normalized Difference Vegetation Index (NDVI). Measured TRAP proxies were weighted road density (WRD) within the buffers and distance to a major road. Generalised Linear Models were used to examine associations of greenery and TRAP with academic scores (adjusted for school socio-educational status), and to identify mediating pathways. RESULTS: Greenery was positively associated with Reading scores in Year 3 (all buffers except 2000 m) and in Year 5 (all buffers), with Numeracy in Years 3 and 5 (all buffers) and with Grammar & Punctuation in Year 5 (all buffers). WRD was inversely associated with Reading scores in Year 5 (all buffers), with Numeracy in Year 3 (all buffers) and Year 5 (300 and 1000 m buffers), and with Grammar & Punctuation in Year 3 (100 and 300 m buffers) and Year 5 (all buffers). Distance to a major road was not associated with any score. TRAP partially mediated associations of greenery within 300 m with Numeracy in Year 3 and Grammar & Punctuation in Year 5, and within 2000 m for Reading in Year 5. CONCLUSIONS: Preliminary evidence indicated that greenery around primary schools was positively associated with Reading, Numeracy and Grammar & Punctuation scores, with TRAP mediating some associations. Further research is required to improve TRAP exposure assessment around schools to verify these findings and inform town/school planners and educators regarding optimal school locations and environments for promoting learning.