The local election season is heating up, and we've got you covered on the storylines you need to know.

💰 Billionaire Michael Bloomberg has an interest in San Francisco politics, having recently contributed $1 million to Mayor London Breed's reelection campaign.

• Even with this boost from Bloomberg, Breed still trails competitor Daniel Lurie by millions. (SF Standard)

🗳️ Mayoral candidate Mark Farrell, meanwhile, has spoken out against a new political action campaign that has labeled him "MAGA Mark."

• Farrell has called it a "smear campaign," and "dirty politics and name calling..." (SF Examiner)

📚 Over in District 11, frontrunner supervisor candidate Michael Lai is defending some of the practices at his early education company, Tinycare, amid claims by former teachers about low wages and less than ideal working conditions.

• Lai sold Tinycare to Higher Ground Education last year. (Mission Local)

Elsewhere in the city...

🏡 SF supervisors approved an ordinance this week that seeks to ban the sale and use of rent-fixing software in an attempt to reduce rent prices in the city. (Mission Local)

⚖️ District Attorney Brooke Jenkins has charged the 17-year-old boy suspected of shooting 49ers rookie Ricky Pearsall in Union Square with attempted murder, robbery and other offenses.

• The boy made his first court appearance yesterday. (SF Chronicle)

🥼 UCSF officials want to build a proton-beam therapy center for cancer treatment at the old Potrero Power Station near its Mission Bay campus. (SF Examiner)

👀 Sheryl Davis, executive director of the city's Human Rights Commission, has requested a spending audit of the Dream Keeper Initiative, a program designed to support the city's Black residents. (SF Standard)

Smoke from the massive 2018 California wildfire significantly worsened asthma symptoms among kids in the Bay Area, according to a new study.

Why it matters: Wildfires have become more frequent and extreme worldwide due to climate change.

• Researchers have found that wildfire smoke and carbon dioxide can damage the lungs, contribute to cardiovascular issues and trigger strokes.
• That compounds adverse health effects that many communities in the U.S., especially of color, already experience from air pollution.

Driving the news: To study the effects of the Camp Fire — the deadliest and most destructive in modern California history — researchers used map data from platform Komodo Health and analyzed health outcomes and hospital visits from 1.6 million pediatric asthma patients in the San Francisco Bay area.

By the numbers: They found rates of asthma exacerbation, such as worse coughing or more shortness of breath, increased 76% in the 14 days after the fire started.

• The rates increased 95% for "Hispanic/Latino" kids, 75% for Asian American and Pacific Islander children, 63% for Black children and 55% for white children.
• Overall, the wildfires were linked to 27% more emergency visits to a doctor from child asthmatics.

Flashback: The Bay Area's air quality index was over 150, which is classified as "unhealthy," for 12 consecutive days, peaking higher than 250 in San Francisco, according to an article in the Bulletin of the American Meteorological Society.

What they're saying: The researchers say the data points to how authorities could address the issue, including targeted distribution of protective equipment like masks and air filters, or investment in clean-air shelters.

What we're watching: The effects of this year's fire season on air quality.

Go deeper

A single percentage point might not seem like much, but it can save San Francisco-area buyers thousands of dollars a year on their mortgage payments.

By the numbers: If you bought a median-priced ($1.51 million) San Francisco-area home in July and put 20% down, you'd be paying an estimated $8,835 per month for your mortgage at an 8% interest rate, compared to $8,010 at 7%, per Redfin.

• That's a difference of $9,900 per year.

The other side: When you put it in a chart like this, it's easy to see why homeowners with those 3% rates won't be moving anytime soon.

After five years living in San Francisco, I finally took a ride on the Boat Tram and my life has changed.

State of play: I have been indoctrinated into the world of Boat Tram. I am obsessed with it. I shall now measure my days as BBT and ABT (Before Boat Tram and After Boat Tram).

Catch up quick: There were 12 open-topped boat trams built in Blackpool, England, in the 1930s, and only eight of them have survived. Three remain in Blackpool, two live in museums (cue Indiana Jones voice) and the remaining three are here in San Francisco.

The vibe: The beautiful streetcar is a perfect SF ride on a sunny day. I rode all the way from Fisherman's Wharf to the Castro (a trip that took roughly 80 minutes) and I loved every wind-swept moment.

Thought Bubble: I sat next to a local who has lived in SF for 40 years but never taken a ride. They were giggling delightedly the whole way.

Stop by: The Boat Tram is riding San Francisco's iconic F route between the Castro and Embarcadero every Sunday and Monday until October. MTA says service will wrap up around Fleet Week.

Pro tip: Check the live streetcar map to find the tram's location and the other historic streetcars in service on any given day, in real time!

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