en: A Stage One alert is declared when ozone readings exceed 0.20 parts per million during a one-hour period . A Stage 1 episode is declared when ozone levels reach 0.20 parts per million .
ms: Amaran Tahap Satu diisytiharkan apabila bacaan ozon melebihi 0.20 bahagian per juta dalam tempoh satu jam. Episod Tahap 1 diisytiharkan apabila tahap ozon mencapai 0.20 bahagian per juta.