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Should public transportation be free in cities with bad air quality?

The views expressed are those of the author and are not necessarily those of Scientific American.

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This weekend, Parisians and those visiting the city will enjoy free public transportation as they move from Versailles to La Tour Eiffel. This initiative comes as much of Northern France experiences dangerously high levels of local air pollution, leaving local governments desperate to get cars off the road.

According to air quality measurements across the country, concentrations of PM10 (particulate matter with diameters of less than 10 microns) are alarmingly high.  The country has recommended that residents avoid being outdoors, stay away from intense physical activity, and reduce driving speeds (or avoid driving completely, if possible). In Lower Normandy, air pollution levels have hit record levels.

France is not alone in their struggle with air pollution. In China, air quality concerns have reached a point where some companies are looking to compensate employees for living in these polluted environments. Yesterday, Panasonic announced that it would give its expat workers a wage premium to compensate for the country’s hazardous air pollution levels.

One of the primary hazardous air pollutants in both France and China is particulate matter (PM), a mix of liquid and solid particles that can contain sulfates, nitrates, ammonium, carbon, metals, and an array of allergens. PM is described by the size of the particles, measured in micrometers or microns. PM10 is shorthand for particulate matter that is less than 10 microns in diameter. In Europe, 50-70% of PM10 is actually PM2.5. That is, very mix of very fine particles less than 2.5 microns in diameter.

Both PM10 and PM2.5 are regulated in much of the world. The World Health Organization (WHO) sets recommended concentration levels according to the potential health impacts of different pollutants. In the case of particulate matter, these impacts include asthma and other respiratory illnesses, lung cancer and cardiopulmonary mortality. Globally, an estimated 800,000 early deaths occur each year as the result of combustion-related emissions (both particulate matter and ozone).

While these particles can come from non-human sources (e.g. volcanoes), anthropogenic sources are the major contributors in cities. PM10 primarily comes from combustion – in car engines (both diesel and petrol), power plants (coal, lignite, heavy oil and biomass), and other industrial activities (for example mining, the manufacturing of cement, and smelting). Therefore, it makes sense that Paris is trying to get cars of the road as a quick fix to current air quality concerns.

This brings about the question – should public transportation be free in cities that are chronically plagued with air quality troubles?

Using centralized public transportation can help regions to more directly control local air pollution. Cities plagued with air quality problems can switch to cleaner diesel buses and electric trains. Thousands of government-owned buses are certainly easier to clean up than tens of thousands of privately-owned vehicles.

Furthermore – as the French have realized – the same public transportation system can be used to encourage people to keep their cars off the road (and the pollution out of the air) in the first place.

Photo credit:

1. Photo of Eiffel Tower by DavidDennisPhotos via Creative Commons.

2. Photo of Beijing in 2005 after two days of rain and during a smoggy day by Bobak via Wikimedia Commons.

Melissa C. Lott About the Author: An engineer and researcher who works at the intersection of energy, environment, technology, and policy. Follow on Twitter @mclott.

The views expressed are those of the author and are not necessarily those of Scientific American.

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Comments 14 Comments

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  1. 1. Johnny Chimpo 10:34 am 03/14/2014

    Why not simply increase the tax on fuel?

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  2. 2. SAULT18 11:30 am 03/14/2014

    Tax the fuel to pay for the free public transportation. I thought Europe was doing this in some form or another, but it apparently isn’t enough. I’m also surprised that Paris’ air quality is so bad. While I saw tons of cars there a few years ago, the air was fairly clean and I did not see any major industrial sources of pollution either. Maybe I just got lucky and they have poor air circulation during certain times of the year.

    Electric cars, better and more extensive bike lanes, and cleaner fuels can help mitigate their air pollution problems as well.

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  3. 3. MoEnergySci 1:15 pm 03/14/2014

    Some cities use congestion charges that assess a fee on cars that travel in the city center. That would be a more direct approach to addressing the local air pollution question. It would also help to avoid disproportionate taxes on long-haul trucking, etc.

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  4. 4. jtdwyer 4:46 pm 03/14/2014

    As I understand, some cities are simply located in areas that do not allow the dispersal of atmospheric pollution (i.e., the L.A. basin). Perhaps those cities should also strive to significantly _reduce_ their populations!
    Also – it should be clear that public transportation should be paid by those who benefit from it, whether they use it or not – the federal government does not need to be paying for the transportation of those who live in areas that cannot manage their pollution!

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  5. 5. SAULT18 5:13 pm 03/14/2014


    Everybody benefits from the cleaner air and lower traffic congestion that public transit provides.

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  6. 6. kjetilk 5:45 pm 03/14/2014

    I live in Oslo, Norway, where we already have heavy taxes on fuels, and let me first state that I’m perfectly OK with the general taxation level we have here (which isn’t as bad as some make it out to be, I paid 29% on my USD 100000 salary), in my opinion fuel taxation fails to acheive the desired outcome. Reliable, highly available and punctual public transport is a must. I think it makes sense to have free public transport in pressure areas, not necessarily to combat air polution directly, but rather to save the costs and the grief of having to collect the fees (people who are tasked with this, I’m sorry to say, usually forget I’m their customer).

    For example, to my previous workplace, I should have had a 40 minute commute each way by public transport. That would have been acceptable, and I decided to give it a try for one month, and in that month, it only worked out once. It was rarely below an hour, and often it would take the double of that. Compared to the car that took 20-25 minutes, and the bicycle, that took 35 minutes downhill and 45 minutes uphill, but the season is limited. The trouble is that the time I could spend with my wife and kids is priceless. Essentially, a tax then is about comparing something that has a price tag with something that’s priceless. If you can at all afford it, the car wins. And if you can’t afford it, then it means that your productivity is going down, which is a bad deal both for the person and society.

    Thus, I think taxation on fuel is not the right way to approach this problem. One has to figure out a way to fund reliable public transport first, so it becomes a viable option for everyone.

    Taxation isn’t evil by itself in my book. As I said, I think taxation makes sense in many cases, but not in this one.

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  7. 7. MoEnergySci 5:48 pm 03/14/2014

    Completely agree that reliable public transportation is the key. If you know that you can get to work or to your child’s school in a certain amount of time, then you can plan around that. When the time that it takes is variable to the point where you can no longer plan your day effectively, then you go back to your car.

    For big cities (that are relatively compact), a combination of public transportation and electric vehicles (or other vehicles without local air emissions) could be the key.

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  8. 8. Jerzy v. 3.0. 5:38 am 03/17/2014

    I also have a horror of living in a city where Greens are fighting cars – but not providing alternative. Public transport is rare. Suburbs and neighboring towns, where many people live, are not served at all outside working hours. There are bike paths, but they turn into death traps when there is frost. And nobody actually thought about time it takes to bike from one end of the town to another.

    Problem is, that it is easy to raise taxes, but buying buses and building suburban railways is too difficult for most city councils.

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  9. 9. Jerzy v. 3.0. 5:45 am 03/17/2014

    ‘For big cities (that are relatively compact), a combination of public transportation and electric vehicles (or other vehicles without local air emissions) could be the key.’

    In my city, this is unfortunately a trap. Greens who run the city council live in the compact city center. So the public transport is limited to the centre. They don’t realize that most people live in suburbs and neighboring satelite towns and must get in and out, and between them, too.

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  10. 10. rshoff2 6:49 pm 03/17/2014

    Public transportation should be free. Period. It’s public. It’s not a money maker. When we look to public services to ‘pay for themselves’ we are losing the focus of the entire purpose of a public service. It benefits all of us in many, and sometimes different, ways.

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  11. 11. rshoff2 6:51 pm 03/17/2014

    Jerzy – I live in a region where we have no ‘urban’ run transportation system. It’s all county and regional. Therefore, it is very inconvenient to get around the city without a car. But if you want to leave the city with out a car, no problem. But why would I want to do that?

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  12. 12. rshoff2 6:58 pm 03/17/2014

    @Jerzy – I completely sympathize with your feeling on the war on cars issues. Cars aren’t going away. They will change. They will become more expensive and more efficient. But we will adjust. And cars will make a resurgence (if they ever really decline). When that happens, we will have irreperably bastardized our transpiration system to the point that nothing works. No roads, no rail, no busses, no transportation. Yet consultants get paid to express opinions about why nothing works. China will be driving the new energy efficient cars while we are reduced to rickshaws.

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  13. 13. rshoff2 6:59 pm 03/17/2014

    transpiration = transportation (of course).

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  14. 14. Jerzy v. 3.0. 5:53 am 03/18/2014

    Net income from tickets in public transport is usually insignificant in the city budget. Aother reason for free public transport – but first make this transport functional, of course.

    I am not sure if we understood each other. 100,000s of people want to leave every big city without the car, every day and often twice a day. They are people who LIVE in the suburbs and satelite towns. Otherwise, they must bring their cars to the city to work, shop, play, entertain themselves, visit friends.

    That is why a public transport should cover ENTIRE urban agglomeration, ESPECIALLY outskirts and satellite towns. And not just during rush hours, fainting to one slow bus per hour in the evenings and weekends. Unfortunately most cities fail here.

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