Recently, I found myself locking horns with a SMART train believer. They had fully bought into Measure Q, which passed by a narrow margin based, amongst other wording, on the premise:
"To... fight global warming...all funds supporting these environmentally responsible transportation"
My adversary, perturbed by my failure to buy into this green train, and pointing to conclusive analysis that showed that the train will certainly increase CO2 emissions asked:
“I'm also wondering if you looked at the emissions issue pertaining to other greenhouse gasses like NOx. I just want to make sure you are not being selective about the facts you are sharing.”
This seemed like a fair question. So I started to dig. Many readers may already be aware Nitrogen Oxides only represent 5% of man made greenhouse gas emissions, while CO2 dwarfs this at 82% of anthropological greenhouse gas emissions. But Nitrogen oxides are far more harmful…
Googling "Nitrogen Oxides, living near effect on health" turns up a litany of studies and articles documenting the high impact these gases have on the respiratory system – particularly on children.
How Much NOx Do Cars In Marin Emit?
Looking at EMFAC / CARB for gasoline cars (LDAs) in Marin in 2017, aggregate speed and season, emissions of NOx are 0.088g NOx per vehicle mile. A caveat – to increase accuracy one one might aggregate cars and light trucks to weight the distribution of gasoline, diesel, hybrid and electric vehicles - a mix which is steadily improving for cars and that will be unique to Marin.
How Much NOx Will the SMART Train Emit?
According to SMART, for a roundtrip between Larkspur and Cloverdale - 140 miles - emissions of NOx and NMHC would be 1,175g, which translates to 8.4g per mile. The actual number would be higher when this is translated to revenue miles to take into account deadhead miles .
Source: Page 17, table 3: SMART Vehicle Study
Compare this with car NOx emissions of 0.088g per mile (Source California Air Resources Board EMFAC data for average car on the road in Marin in 2017). That makes SMART 95 times higher NOx emissions than gasoline cars, and this gap is only widening as cars are becoming cleaner much faster than trains.
Applying the APTA mode shift factor of 42% of train riders will be former car occupants, this means SMART would need 227 average daily riders (per train) to breakeven and reduce NOx emissions. Even the New Jersey Hudson Line running alongside Manhattan in a dense urban area has an average ridership of only 33 riders. Portland’s light rail is under 25. To presume that SMART - a train serving rural and suburban Marin - would come close, let alone exceed a ridership of 227 is to be spinning a fairy tale.
It's worth mentioning some caveats in these calculations:
- deadhead miles (positioning, maintenance) are not considered would make the SMART emissions worse;
- SMART emissions include NMHC (non methane hydrocarbons) while the car figures do not (EMFAC does not appear to show NMHC figures or combined NOx/NMHC figures).
So once again the evidence shows that not only will SMART certainly raise CO2 emissions significantly, it will very likely do the same for the highly toxic and greenhouse gas of Nitrogen Oxide.
What if Measure Q Had Been Accurate?
If Measure Q had accurately reflected that the train is certain to increase CO2 and NOx emissions would it have passed? The old saying goes “all that glitters is not gold”. Perhaps it should be updated in a world rightly obsessed with fighting climate change to “all that glitters is not green”.