Teach­ers, leave them win­dows open

Marlborough Express - - FRONT PAGE -

Win­dows in New Zealand pri­mary schools should be opened more of­ten to com­bat air pol­lu­tion, a new study has found.

‘‘There is a need … to re­duce ex­po­sure to in­door air pol­lu­tion at schools,’’ re­ported lead au­thor Dr Julie Ben­nett.

She and col­leagues tested the in­door and out­door air qual­ity at an un­named Welling­ton pri­mary school in Oc­to­ber 2016. It was a clas­sic class­room from the 1970s – a one-storey, pre­fab­ri­cated, weath­er­board build­ing prob­a­bly de­signed to be tem­po­rary but still go­ing.

The sin­gle class­room tested was not in­su­lated, the roof was cor­ru­gated steel and the floor car­peted. Heat came from an elec­tric fan heater and ven­ti­la­tion was sup­pos­edly pro­vided by open win­dows on both sides. A busy road passed the school gates.

But the win­dows weren’t opened enough and var­i­ous types of air pol­lu­tion built up over the day.

The re­searchers mea­sured the lev­els and sources of car­bon diox­ide, ni­tro­gen diox­ide, par­tic­u­late mat­ters 2.5 and 10, tem­per­a­ture, hu­mid­ity and other fac­tors.

They found that in­door PM10 lev­els were ‘‘sig­nif­i­cantly … higher’’ than out­door con­cen­tra­tions. Anal­y­sis found the PM10 prob­a­bly came from soil brought into the school room on shoes.

PM2.5 lev­els were also found to be sig­nif­i­cantly higher in­doors than out. PM2.5 was thought to come from the ex­hausts of pass­ing ve­hi­cles.

PM10 is par­tic­u­late mat­ter 10 mi­crom­e­ters or less in di­am­e­ter, while PM2.5 is par­tic­u­late mat­ter 2.5 mi­crom­e­ters or less in di­am­e­ter and of­ten de­scribed as ‘‘fine par­ti­cles’’, ac­cord­ing to the Aus­tralian Na­tional Pol­lu­tant In­ven­tory. About 40 fine par­ti­cles could be placed on the width of a hu­man hair.

Th­ese tiny par­ti­cles are drawn deep into the lungs and some­times into the blood.

‘‘Poor in­door air qual­ity im­pacts stu­dents’ cog­ni­tive func­tion and de­vel­op­ment, com­fort, con­cen­tra­tion and per­for­mance,’’ wrote Ben­nett, a re­search fel­low at the De­part­ment of Pub­lic Health at the Uni­ver­sity of Otago, Welling­ton cam­pus.

Ben­nett and col­leagues cited in­ter­na­tional stud­ies show­ing pri­mary school chil­dren ex­posed to high lev­els of traf­fic-re­lated air pol­lu­tion had slower cog­ni­tive de­vel­op­ment than chil­dren at­tend­ing lower pol­luted schools. A re­cent study from Barcelona found pri­mary chil­dren ex­posed to air pol­lu­tion while at school had in­creased be­havioural prob­lems.

A study of air qual­ity in 51 Por­tuguese schools re­ported high lev­els of car­bon diox­ide im­pacted cog­ni­tive func­tion and there­fore learn­ing.

Res­pi­ra­tory and car­dio­vas­cu­lar sys­tems were also af­fected, es­pe­cially in chil­dren.

Asthma, a res­pi­ra­tory con­di­tion, causes hospi­tal­i­sa­tion and school ab­sen­teeism. The link be­tween air pol­lu­tion and car­dio­vas­cu­lar health got less at­ten­tion in the re­search lit­er­a­ture but ‘‘may be as sig­nif­i­cant as on lung health’’, Ben­nett and her seven coau­thors re­ported in the jour­nal At­mo­spheric Pol­lu­tion Re­search.

Ben­nett’s team also found el­e­vated lev­els of car­bon diox­ide in the class­room. This al­most cer­tainly came from chil­dren and teach­ers breath­ing.

Many of th­ese prob­lems could be ad­dressed if win­dows were opened more of­ten, es­pe­cially to cre­ate cross ven­ti­la­tion. Sev­eral in­ter­na­tional stud­ies have shown that high ven­ti­la­tion rates in class­rooms im­prove chil­dren’s health and school at­ten­dance. Ben­nett wrote that about 90 per cent of New Zealand class­rooms are de­signed to be ven­ti­lated by win­dows.

Many new class­rooms and some re­fur­bished ones have sys­tems that au­to­mat­i­cally open win­dows or sky­lights for ven­ti­la­tion.

Schools should also drop car­pets, as they col­lect dust and are harder to clean than hard floors, Ben­nett said in an in­ter­view. Al­though a case study of a sin­gle class­room, Ben­nett ex­pected ‘‘most schools would have sim­i­lar re­sults to this’’.

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