Bill de Blasio kicked off of his 2020 presidential campaign on Thursday, making the New York City mayor the 24th person to join the crowded Democratic field.

The big picture: Even before his announcement, de Blasio already qualified to participate in the Democratic primary debates, according to a poll from Reuters and Ipsos. The mayor intends to leverage his record of New York achievements such as universal pre-kindergarten and raising the minimum hourly wage. Following the announcement, he will go on a 4-day campaign tour to Iowa and South Carolina, per NBC.

Go deeper: "We know the game is rigged": NYC mayor slams Amazon HQ2 reversal

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Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Global: Total confirmed cases as of 10 a.m. ET: 19,412,292 — Total deaths: 722,066 — Total recoveries — 11,773,112Map.
  2. U.S.: Total confirmed cases as of 10 a.m. ET: 4,945,795 — Total deaths: 161,456 — Total recoveries: 1,623,870 — Total tests: 60,415,558Map.
  3. Politics: Trump says he's prepared to sign executive orders on coronavirus aid.
  4. Public health: Fauci says chances are "not great" that COVID-19 vaccine will be 98% effective
  5. Science: Indoor air is the next coronavirus frontline.
  6. World: Africa records over 1 million coronavirus cases — Gates Foundation puts $150 million behind coronavirus vaccine production.
2 hours ago - Health

Indoor air is the next coronavirus frontline

Illustration: Eniola Odetunde/Axios

A growing body of research has made it clear that airborne transmission of the coronavirus is possible.

Why it matters: That fact means indoor spaces can become hot spots. Those spaces also happen to be where most business and schooling takes place, so any hope for a return to normality will require better ways of filtering indoor air.

The silver linings of online school

Illustration: Annelise Capossela/Axios

Online learning can be frustrating for students, teachers and parents, but some methods are working.

The big picture: Just as companies are using this era of telework to try new things, some principals, teachers and education startups are treating remote learning as a period of experimentation, too.