A scramble for N95 masks in Singapore as the haze situation worsens, with one retail chain imposing daily purchase limits to ensure all customers can have access. But even with a big spike in demand for masks, merchants have pledged not to raise prices. One environment expert says while N95 masks are effective against haze particles, reusable masks can do the same job. However, he warns against reusing a N95 mask as it might have been saturated with particles captured over time. Meanwhile, vending machines dispensing free N95 masks are emptying out faster than authorities can restock them.