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You might want to consider doing some research before just mindlessly dismissing what other people say. “Mobile sources of air pollution from cars, trucks, shi

You might want to consider doing some research before just mindlessly dismissing what other people say. “Mobile sources of air pollution from cars, trucks, ships, emissions from construction equipment, and tire and brake wear on roadways are the biggest root cause of poor air quality in the city, and addressing these should result in positive air quality trends.” https://sfgov.org/scorecards/environment/days-epa-air-quality-index-rating-good https://sfgov.org/scorecards/environment/days-epa-air-qualit...

hajile 6y ago
That is grossly misleading because one of those things is very much not like the others. Ships measure fuel in tons per hour. It only takes a few hundred transport ships to put out as much pollution as every car on the planet and there are hundreds of thousands of them with their collective output dwarfing cars and trucks combined by several orders of magnitude. If we really wanted to cut transportation pollution fast, we'd internationally mandate turbosails on all transport ships as current models cut fuel consumption by 25% or more. Stepping aside from ships, big rigs are the overwhelmingly biggest NOx contributors (even beating out industrial and power plants). Stepping back though, transportation in ALL its forms still only contributes around 1/4 of the US greenhouse emissions.
- akamaka 6y ago
  What’s misleading about it? We are talking about the health effects on people living in cities in California, not about cargo ships burning dirty fuel in the middle of the ocean or general global greenhouse gas emissions. It is a true statement that vehicle traffic is a major source of harmful pollution in US cities.
seanmcdirmid 6y ago
When there is a forest fire going on? If your AQI is at 800 because a forest fire is raging nearby, driving less isn't going to change that number at all. You simply have bigger problems than auto exhaust at that point.
- akamaka 6y ago
  Do you imagine that there is some hard limit beyond which adding more pollution won’t make any difference to someone’s health? Or is the relationship more linear, where every additional particle inhaled will cause more damage?
  - seanmcdirmid 6y ago
    If you don’t get rid of the forest fire, you are screwed either way. Driving less maybe takes you from 60 to 30, it won’t have any impact at 800. Driving less is a good thing, it’s just not something that is going to help with forest fire pollution. Think about the difference between peeing or not into a clear body of water and a muddy swamp. Either way, you don’t want to drink from the muddy swamp.

hajile 6y ago

That is grossly misleading because one of those things is very much not like the others. Ships measure fuel in tons per hour. It only takes a few hundred transport ships to put out as much pollution as every car on the planet and there are hundreds of thousands of them with their collective output dwarfing cars and trucks combined by several orders of magnitude. If we really wanted to cut transportation pollution fast, we'd internationally mandate turbosails on all transport ships as current models cut fuel consumption by 25% or more. Stepping aside from ships, big rigs are the overwhelmingly biggest NOx contributors (even beating out industrial and power plants). Stepping back though, transportation in ALL its forms still only contributes around 1/4 of the US greenhouse emissions.

akamaka 6y ago
What’s misleading about it? We are talking about the health effects on people living in cities in California, not about cargo ships burning dirty fuel in the middle of the ocean or general global greenhouse gas emissions. It is a true statement that vehicle traffic is a major source of harmful pollution in US cities.

seanmcdirmid 6y ago

When there is a forest fire going on? If your AQI is at 800 because a forest fire is raging nearby, driving less isn't going to change that number at all. You simply have bigger problems than auto exhaust at that point.

akamaka 6y ago
Do you imagine that there is some hard limit beyond which adding more pollution won’t make any difference to someone’s health? Or is the relationship more linear, where every additional particle inhaled will cause more damage?
- seanmcdirmid 6y ago
  If you don’t get rid of the forest fire, you are screwed either way. Driving less maybe takes you from 60 to 30, it won’t have any impact at 800. Driving less is a good thing, it’s just not something that is going to help with forest fire pollution. Think about the difference between peeing or not into a clear body of water and a muddy swamp. Either way, you don’t want to drink from the muddy swamp.