It is too soon to get an accurate gauge of how many renters withheld their April rent and what the fallout would be for landlords.

But Mr. Salerno said in an interview on Thursday that he did not care about losing his rental income in April, nor did he care to calculate the amount that he would not be collecting from his 80 apartments. He said he had about 200 to 300 tenants in total.

He is likely forgoing hundreds of thousands of dollars in income by canceling April rent.

His only interest, he said, was in alleviating stress for his renters, even those who were still employed and now working from home.

“My concern is everyone’s health,” said Mr. Salerno, 59, whose rent gesture was first reported by the local news site Greenpointers.com. “I told them just to look out for your neighbor and make sure that everyone has food on their table.”

Mr. Salerno said a handful of his tenants messaged him last month saying that they could not afford rent. Three renters from Ireland packed up a few belongings and moved back home, he said.

When Mr. Gentile spotted the sign last week, he said he was surprised but not shocked. For the nearly four years Mr. Gentile has lived in the apartment, Mr. Salerno has been a model landlord.

Emergencies are fixed almost immediately, he said, such as a water leak in Mr. Gentile’s ceiling that was fixed, patched and painted within several hours.