How the wildfire smoke is affecting Boston's air quality

It’s (mostly) safe to breathe today. The worst of the haze from Canada’s wildfires is over for Greater Boston.

What's happening: The Boston area faced the brunt of the smoke on Tuesday and early Wednesday, prompting the state to issue an air quality alert.

• Winds are pushing the haze farther west and mitigating the impact on us the rest of the week, says Bill Leatham, meteorologist at the National Weather Service Boston.

Why it matters: Breathing unhealthy levels of smoke and other air pollution can increase someone’s risk of developing lung and heart conditions, per the Environmental Protection Agency.

• For those with pre-existing lung and heart conditions, the poor air quality can also trigger asthma and heart attacks, which can be fatal.

Catch up fast: Smoke has triggered air quality alerts for millions of people across the northeastern U.S., writes Axios’ Jacob Knutson.

How it works: The EPA's Air Quality Index (AQI) had Boston at AQI levels ranging from 42 to 92 during the day yesterday.

• An AQI of 0 to 50 is considered "good" air quality, while 51 to 100 is considered "moderate" quality.
• Any value above 100 is considered to be unhealthy, especially for sensitive groups of people.

• At levels between 151 and 300, everyone is recommended to either reduce or avoid intense activities outdoors.

🧠 Be smart: Most of us should be OK today and tomorrow, but the lingering air pollution could still harm elders, young children and people with asthma and other respiratory illnesses, Leatham says.

• They should stay inside for the next couple of days.
• The American Veterinary Medical Association recommends that pet owners keep animals indoors as much as possible and keep windows shut during periods of poor air quality, as they are also affected by air pollution — especially birds.