In developed countries, the two most deadly sources of indoor pollution are _____?

ترقی یافتہ ممالک میں، اندرونی آلودگی کے دو سب سے مہلک ذرائع کونسے ہیں؟

radon and cigarette smoke

pesticides and cleaning agents

radiation from electronic equipment and pesticides

pesticides and cigarette smoke

All of these

Cigarette smoke and radon are two of the most common indoor hazards.

Most people spend upward of 90% of their time indoors. Without proper ventilation, many pollutants can accumulate indoors.