How did you decide when it was reasonable to ventilate after smoke? / 烟雾减轻后，你怎样判断何时可以通风？

What local air-quality signal or indoor condition did you rely on? Share the decision process, not a universal threshold, because buildings and local advice differ. 你参考了哪些本地空气质量信息或室内状况？请分享判断过程，不要把单一阈值当成普遍结论。