In 2015, it was disclosed that the water supplied at several Hong Kong public housing estates contained dangerous amounts of lead. The level of lead in the water samples taken from the area exceeded the World Health Organization’s guideline of 10 micrograms for drinking water. Lead poisoning can cause multi-organ failure and damage the nervous system. This unexpected incident resulted in a significant increase in household purchases of water filters. Which determinants of demand were the most likely factors in the households’ decisions to purchase water filters? How would these purchases affect the demand curve for water filters?