Air Pollution, Heath, and the Role of EVs

How much does poor air quality affect our health and do EVs really make a difference?




You see it, you smell it, you know it’s there, a disconcerting certain something in the air that all too many assume to be an unchangeable fact of urban life, and resign themselves to it. It’s vehicle exhaust, and it contributes to air pollution-related illness, disease, and early deaths of millions worldwide, slowly. The World Health Organization reports that in 2012 around 7 million people died as a result of exposure to air pollution, linking it to 1 in 8 global deaths annually.1

“Few risks have a greater impact on global health today than air pollution; the evidence signals the need for concerted action to clean up the air we all breathe” said Dr Maria Neira, Director of WHO’s Department for Public Health, Environmental and Social Determinants of Health in a release by the WHO. “The risks from air pollution are now far greater than previously thought or understood, particularly for heart disease and strokes.”

Air pollution is the world’s single largest environmental health threat. Are there other options; what can be done; is it all in the hands of governments or industry, and what can individuals do?


Air pollution’s major effects on health

A breakdown of air pollution’s estimated impact on life expectancy seen in terms of minutes of life lost per day can be striking. Research findings from an authoritative study published in the New England Journal of Medicine, indicate that for every increase of 10 μg/m3 in the annual mean concentration of PM2.5 (fine particulate matter penetrating into the lungs and bloodstream), average life expectancy decreased by 15 minutes per day.2 Extrapolating from this, living in London shaves roughly 7.5 minutes per day off Londoners’ lives; Taipei takes off 13.5 minutes of life per day; Taichung, Tainan, or Hong Kong cuts off 28 minutes per day; and living in Beijing takes away closer to an hour of life per day. In total, these daily amounts can be estimated to remove months to years off of a lifespan.

Air pollution is a major risk factor for cancer, the leading cause of death in Taiwan. Every 13 minutes, a cancer death occurs in Taiwan, and 1 in 5 of those is from lung cancer, the most common form. A 2013 European found that for every increase of 5 μg/m3 in the mean concentration of PM2.5, the incidence of lung cancer rose 18%.

The specialized cancer agency of the World Health Organization, the International Agency for Research on Cancer (IARC), classifies outdoor air pollution as a Group 1 carcinogen, and classes PM2.5, separately, as a Group 1 carcinogen as well, similar to asbestos and tobacco. Short-term spikes can trigger asthma attacks, strokes, and heart failure among groups most sensitive, according to the American Lung Association.

Vehicle emissions are a major source of air pollution and the number one source of urban street-level pollution affecting health, constituting a significant risk factor for cardiopulmonary disease, stroke, lower respiratory tract disease, cancers, and asthma. The most severe effects of air pollution are typically cumulative and long-term, and less perceptible day-by-day, outside of sensitive groups. Taiwan’s aging population is particularly vulnerable, and, at the other end of the spectrum, up to 20% of first graders in Taipei suffer from asthma, according to the Taiwan Association of Asthma Education.

“As urban air quality declines, the risk of stroke, heart disease, lung cancer, and chronic and acute respiratory diseases, including asthma, increase. When dirty air blankets our cities the most vulnerable urban populations – the youngest, oldest and poorest – are the most impacted,” said Flavia Bustreo, WHO Assistant Director General.

In addition to vehicle-based air pollution, traffic noise pollution is an aggravator of mental stress, taxing on the nervous system, and a detriment to well-being when prolonged and inescapable. Though the bulk of previous research defines pollution’s impact on the heart and lungs, newer research also explores links to brain disease.

Talk of decreased lifespan may be written off by those who are healthy now, or who see the loss of months or years at the end of their lives as a distant and barely imaginable prospect. But what is truly at hand, is not just shortened lifespans, but the loss of quality of life during what should otherwise be memorable years, before ending in periods of struggle with a debilitating condition that shifts the number of good healthy years down. Life is nothing without health, and most people are aware that quality matters more than quantity.


Pollution from space, as captured by the NASA Earth Observatory


Air pollution: what it is and where it comes from

The primary outdoor pollution sources are vehicle emissions, energy generation via fossil fuels, manufacturing and industry, and the burning of materials (biomass in all forms, including crops, trash, paper, and wood for heating and cooking). Transportation consumes the largest share of liquid fossil fuels, and vehicle emissions represent the greatest source of urban street-level pollution affecting health.

Vehicles collectively generate substantial amounts of particulate matter (PM2.5, PM10), including partially combusted hydrocarbons (HC), black carbon (BC), and nitrogen oxides (NO2, NOx), sulfur dioxide (SO2), carbon monoxide (MO), and ozone forming compounds. Experts are most concerned about the level of PM2.5, fine airborne particles 1/30th–1/60th the diameter of human hair, which travel into the lungs and bloodstream.

“Excessive air pollution is largely a by-product of unsustainable policies in transport, energy, waste management, and industry. Healthier strategies will also be more economical in the long term due to healthcare cost savings as well as climate gains,” said Dr Carlos Dora, WHO Coordinator for Public Health, Environmental and Social Determinants of Health, in a report.

The proportions and ratios of emission sources vary from region to region. For China, often referred to as the world’s factory, manufacturing and energy generation account for a higher portion of emissions than in Taiwan, where vehicle emissions constitute a greater portion of overall emissions affecting health.

When we look at the three major sources of air pollution – transportation, energy generation, and industry – what may not be immediately apparent is the disproportional effect just one has on the greatest number of people. Air pollutants emitted in close proximity to a population have greater impact. Emissions from power plants and industry are typically generated at a distance from population centers. Vehicles, however, are under our noses and in great numbers. Air pollution’s effect on humans is largely localized, unlike climate pollutants like CO2 which contribute to global warming wherever they are released. Though airborne PM2.5 can travel many kilometers and remain in the air for weeks, proximity plays a role in terms of intensity, and thus vehicle-filled cities are never immune to their emissions. Dilution and dispersion of particles typically increase with distance, unless becoming trapped. Vehicles are the major source of urban street-level emissions affecting health in large population centers around an increasingly urbanized world. Estimating and appreciating the economic cost of vehicle air pollution to society, including healthcare costs, is essential. Economists refer to these as “unpriced externalities”, costs that society picks up the tab for, but which vehicle manufacturers are not held accountable for.


Indoor vs. outdoor pollution, and close traffic, a special danger

Both indoor and outdoor air pollution affect our health, but what is striking and only more recently acknowledged, is that heading indoors does less to protect health than previously thought. PM2.5, finds its way indoors where it remains trapped. Staying inside, where indoor and outdoor sources combine, unfortunately, often does not pose less risk than being outdoors away from traffic.

As surprising as it is that PM2.5 levels indoors are often not significantly different from outdoors levels, it does not prepare one for the fact that in some cases, they can be worse. PM2.5 measurements recently gathered on a busy street in Taipei hovered around 56 μg/m3 (US AQI 150), yet in a nearby café, the concentration rose to 150 μg/m3 (US AQI 200). There are several factors for this: PM2.5 easily enters gaps in the construction of most homes, and once inside, tends to remain trapped, unable to be dispersed. In many cases, interior sources (cooking without a ventilator chief among them), pose an added threat, compounding with other trapped particles.

It is well established that living within 300 meters of major roadways affects lung function, and at 75 meters the change is dramatic. Assuming that it is possible to escape outdoor air pollution by simply heading indoors is wrong.


Pollution in Chinese city


Do EVs make a difference?

Emissions from motor vehicles are the main source of air contaminants in urban areas, according to the US Environmental Protection Agency. Vehicles represent the single largest source of urban street-level emissions affecting health. Gross polluters (with visual tailpipe smoke) can constitute 100x as much pollution as a properly regulated new vehicle, but the collective effect of all internal combustion engine (ICE) vehicles, even when properly maintained, poses a substantial threat. In terms of vehicle types, top individual polluter types remain diesels and old motor scooters, but no combustion engine is safe when considering its effects in aggregate, particularly in high-density urban areas.

The internal combustion engine is simply a very inefficient means of converting BTUs into motion. Power plants are vastly more efficient than ICEs in turning fuel into motion, even when accounting for transmission losses. EVs waste almost nothing in heat and noise, while ICEs waste most fuel energy as heat and noise. An EV can be up to 85% efficient, whereas a gas ICE, on average, has only 20% thermal efficiency.

Though all EVs have zero tailpipe emissions, pollution is of course still generated at the power plant, but what is key to note is that in the overwhelming majority of cases, the amount of pollution is less, and often greatly so. Equally important, power plants are typically never located in the middle of large populations, reducing the impact of their emissions. Furthermore, EVs, provide the essential partner to a zero-carbon future as they may be supplied with electricity from renewables. Whereas, gas vehicles, over time, become dirtier via wear and tear on the engine and other components, EVs in fact become cleaner as the grid incorporates more renewable energy sources. No gas vehicle will ever run on renewables.

Even as EVs begin to displace ICE vehicles today, it is expected to take two decades, at a minimum, to reach 50% displacement even under aggressive mandates. It is therefore key that more EVs enter the fleet now. Electricity grids everywhere will switch to cleaner sources of power. To play a game of chicken or egg, waiting for 100% renewables first before engaging with EVs would be counterproductive. Given that the benefits to zero tailpipe emission vehicles are immediate, and ICE fleet displacement takes many years, starting to switch now is wise.

The myth of the “long tailpipe”

In comparing EVs to ICEs, there exists a misconception that EVs simply move the source of pollution elsewhere, and the overall impact of pollution remains the same. This idea is known as the “long tailpipe”. EVs, however, are not simply shifting an equal amount of pollution elsewhere. The emissions profile of an electric vehicle, even when factoring in the source of electricity generation, is, with very few exceptions, significantly lower than an ICE, as is their overall liftime carbon footprint. It is true that the cleaner the energy source, the cleaner the EV, but even in regions where coal is favored, EVs are still typically cleaner for populations, more efficient, and far cheaper to use per km driven, than equivalent-sized gas vehicles.

The ICE engine is reaching its peak refinement period, with only sparse incremental gains left yet to achieve. Constant tightening of vehicle emissions is a difficult proposition compared to regulating emissions on power plants whose numbers are several orders of magnitude less than vehicles. Policing a billion tailpipes is a vastly more complex affair than controlling emissions at power plants. A modern and efficient power plant, such as a combined cycle gas-turbine plant, or a renewable energy site, provides instantaneous reduction of emissions at the source and for all the EVs.


Scapegoating China

But isn’t the worst air pollution mostly coming from China? It seems a common practice across Asia to blame China, the behemoth in the region, and presume it to be driving a disproportionate amount of air pollution into surrounding nations. China is indeed the single largest CO2 emitter globally, however, it is critical to distinguish CO2, a global warming greenhouse gas (GHG) from air pollutants like PM2.5, NO2, and SO2, which impact human health. China’s emissions of those air pollutants is indeed very significant but chiefly affects populations locally, not internationally. China’s emissions of CO2, in the levels now present, strongly contribute to global warming, but not a decline in health. CO2’s effect on health begins at 600 ppm, but atmospheric levels everywhere are at 400 ppm.

With very few exceptions, the vast majority of pollution within a country affecting local populations is from local sources, and not from abroad. In Taiwan, under certain conditions, some 30% of PM2.5, can be from China, however, the remaining 70%, the lion’s share, is entirely from local sources. Foremost among them affecting the most citizens’ health, is vehicle emissions.


Air pollution and weather

Concentrations of air pollution are greatly affected by meteorology, air currents, and local topographies, causing variations in readings day-to-day, and hour-by-hour, but actual emission sources are well understood. Emission sources are mostly consistent throughout the year, with the same number of vehicles running, industry at a given output, and repeating power demand and traffic patterns. Therefore, to think of pollution like the weather, as local news reports often have the effect of suggesting, embeds it with a degree of unpredictability, a randomness that belies the true constant nature of the sources, be they vehicle use, energy demand, or industry. Weather affects pollution to the extent that it might be dispersed, or trapped, by inversion layers and local topographies, but source output is predictable. We should not regard pollution like the weather, becoming alarmed only on the worst days, but instead, address its constant output, and demystify it.


Differentiating air pollutants from climate pollutants

Many air pollutants such as PM, SO2, NOx, and CO are emitted from the same sources as climate pollutants (GHGs: greenhouse gasses) like CO2. GHGs must be dramatically cut to mitigate climate change. Since the burning of fossil fuels is the primary source of both air and climate pollutants, measures to cut air pollution also address climate change. There is a need to jointly asses them, in line with one of the fundamental messages of the Intergovernmental Panel on Climate Change (IPCC) which emphasized that the co-control of air pollution and GHG emissions creates co-benefits

When air quality improves, health costs from pollution-related diseases decline, productivity grows, life expectancy increases, and quality of daily life improves. Reducing air pollution also brings major climate change benefits, helping nations meet the climate objectives of COP21. However, there is significant lag time between the implementation of GHG reduction measures and seeing the benefits thereof. Climate change models indicate that even if all fossil fuel usage ceased immediately, global warming would still continue unabated for some fifty years. In the talk of decarbonizing the economy, this critical point can go lost. The effects of a century and a half of burning fossil fuels do not end in step with the cessation or reduction of their use, but continue on, reverberating over a half century or more, before a plateau and decline in their effects. Even once the anthropogenic causes of GHG emissions are eliminated, their effects linger. Therefore, the primary benefit to reducing air pollution is in improving quality of life today followed by essential outcomes that ensure a habitable world exists for our grandchildren.

EVs both improve our air and have a much lower “cradle to grave” carbon footprint. Though it is difficult to motivate people to act on behalf of future generations, by successfully dealing with air pollution now and improving quality of life today, we can avoid some of the worse effects of climate change in the future, leaving behind a habitable world. There is much synergistic win-win opportunity to an integrated approach, as reducing air pollution is effectively synonymous with fighting climate change.


Summary and recommendations: driving electric, air filtration, and more

It cannot be emphasized enough that one of the single greatest routes individuals (and thereby nations) can take to mitigate the dramatic effects of air pollution, sufficiently illustrated in this article, is to vote with what they buy, and make the switch to clean EVs as soon as possible. EVs are a vital partner in the energy usage relationship, helping to improve air quality where it matters most, and giving transport a way to partner in moving off fossil fuels.

Air quality measurements have revealed that the difference between indoor and outdoor air, unfortunately, is not as substantial as once assumed. Use of a basic PM2.5 indoor air purifier is recommended, as we typically spend over 85% of our lives indoors, a quarter of it sleeping. An air purifier must have a HEPA filter which, by definition, filters 99.97% of fine particulates, to cut PM2.5 to a negligible amount. A PM2.5 monitor may be used to confirm levels are kept within WHO recommendations, i.e. at or below 10 μg/m3.

The first automaker to supply in-cabin PM2.5 air filtration is Tesla, a feature that the traditional auto industry will be loath to offer, as it is a tacit admission of the health threat represented by their 1.2 billion cars. In-cabin HEPA air filtration should become a widely available option. To the extent that gas and diesel vehicles manufacturers are complicit in creating air pollution, it will take nothing less than the auto-buying public coming to expect both EVs and in-cabin HEPA filtration from them.

Surgical masks, frequently worn in Asia, were never intended for nor suited towards protection from air pollutants like PM2.5. Only certified N95 respirators (or higher) may protect the wearer from PM2.5, if properly-sized and correctly worn, with zero air gaps. Compliance rates are low due to this, but N95 masks with exhale valves increase comfort and are recommended in severe outdoor air pollution.

Engine idling in non-carbureted vehicles (i.e. fuel-injected) is unnecessary, wasteful, and contributes significantly to pollution, fuel consumption, and engine wear. Stopping engine idling, in cars, trucks, and motorcycles, is low-hanging fruit. In Taiwan, for every kilometer a vehicle travels, at least 80 seconds are wasted idling, accounting for some 20% of fuel usage. Scooters waiting more than 10 seconds at a stoplight, and cars waiting longer than 20 seconds, can turn the ignition off, and save the air, fuel, engine wear, and money.

Personally use and support the wide adoption of EVs and renewable energy, as well as electric public transport, vehicle shares, walking, cycling, and don’t forget e-cycling – pedal- assist e-bicycles are a most efficient means of transport. Set an example. Be vocal about your expectations of city and national governments. They can’t do it alone. It is up to all of us to create a movement, and demonstrate receptivity and demand. We know what the solutions entail, and the remaining hurdles are largely no longer technological ones, but mostly educational, social, and political. We can design, engineer, and right act our way out of this. The costs of not doing so, are foolishly, nihilistically high, for us in this world today, and for our children. Most often, the greatest change we can make is to vote with what we drive or ride, and how we conduct our lives.



[Non-medical professional disclaimer; article draws heavily on reports by the WHO and IARC]

1. “World Health Organization: 7 Million Premature Deaths Annually Linked to Air Pollution”

2. “Fine-Particulate Air Pollution and Life Expectancy in the United States” C. Arden Pope, III, Ph.D., Majid Ezzati, Ph.D., Douglas W. Dockery, Sc.D. New England Journal of Medicine. 22.01.09


Writer David Edward Lane
Illustrator Natasha Chiang
Photographers NASA Earth Observatory, Erhard Renz
David Pan
Weeknight magazine is published in two editions, the English and Chinese & English.