For two Delhi teenagers, that change in colour is the most visible sign of what their Rs 140 filter is designed to do: trap some of the fine particles that children would otherwise breathe in while sitting through lessons. New Delhi: Switch on the fan and the white fabric swells like a balloon. Leave it in use for a few weeks and it can turn grey, sometimes black.
Be respectful · TOI community guidelines In classrooms measuring roughly 600-700 sq ft, the model can reduce PM2.5 levels by 50-55% in the first hour and around 90% after several hours of use, Aggarwal said. In a 200 sq ft room, the team estimated a reduction of around 90% within an hour.
If the windows are open, you can’t expect to get those results,” he said. Krish Aggarwal, a Class XII student at Sanskriti School, and Samarth Meattle, a Class XI student at Vasant Valley School, started Project Vayu with a question that had as much to do with school budgets as with Delhi’s air: what could classrooms that could not afford air purifiers use instead? Their answer was something many schools already had — a fan. “A classroom is harder to control, with doors opening and closing through the day.