Deadly NOx pollution

 From The Australian Broadcasting Corporation (ABC)

Imagine you're stopped at the lights and two cars pull up beside you. One is a compact SUV, the other a beefy four-wheel drive that weighs twice as much.

The off-roader has a petrol engine, while the SUV has the low idling growl of a diesel.

You'd probably guess the big car is polluting more. 

And you're right, but also wrong.

The smaller car emits less carbon dioxide (CO2) but it also produces more of another form of car pollution — one that has a much greater immediate public health impact than the CO2.

Nitrogen dioxide (NO2) and nitric oxide (NO) are collectively known as the oxides of nitrogen, or "NOx".

Mostly invisible and regularly ignored, NOx is linked to hundreds of premature deaths each year from conditions such as heart and lung diseases.  

Despite this health toll, drivers are generally unable to find out exactly how much NOx their car emits. 

Now, new publicly available data is exposing which popular models pump out more NOx than others.

It comes as a long-anticipated standards update goes into force today that more than halves how much NOx new diesel models sold in Australia may emit.

Here's how these changes may affect your next car — and the air you breathe. 

Unlike with CO2, you won't find a point-of-sale windshield sticker or a vehicle emissions guide that lists NOx pollution.

Cars sold in Australia must emit less NOx than mandated maximums, under rules last updated nine years ago.

These rules are enforced by laboratory testing of new models. Tyres are spun on a giant treadmill while exhaust gases are funnelled, split, and measured.

But lab-testing doesn't necessarily show how much cars pollute on the road.

The Australian Automobile Association (AAA) recently strapped emissions measurement systems onto more than 100 of the most popular cars, utes [pick-up trucks] and vans. They drove these modified vehicles around Geelong in real traffic conditions, following strict protocols for speed and acceleration.

Their testing revealed many cars consumed more fuel and emitted more pollution than lab tests showed.

And some of the biggest discrepancies were for NOx emissions.

The petrol cars were generally under the limit. Two of the 90 petrol cars tested emitted more NOx than the mandated maximum of 60 milligrams per kilometre.

But most of the diesel cars flunked the test.

Seventeen of the 24 diesels tested emitted more than the cut-off limit for commercial or passenger models, which is 280 milligrams per kilometre and 180mg/km respectively (two to three times higher than the limit for petrol cars).

On average, diesel vehicles exceeded their mandated maximums by almost 40 per cent [and remember, the emissions standard for commercial vehicles is 3 - 4 times higher than for petrol cars]

And this wasn't for a new emissions standard. The maximum had been in place since 2016.

Dots on a graph may not look too dangerous, but incremental changes in NOx emissions have a measurable impact on public health, when multiplied by the millions of cars.

If you stand beside a busy road and count the passing cars, about one in every 10 vehicles burn diesel.

Diesel vehicles are less common than petrol ones but emit far more NOx (based on the AAA's data, about 20 times more).

NOx exposure is associated with the majority of deaths from traffic pollution, so the relatively few diesel cars have a disproportionately high public health impact.

Research led by the University of Tasmania's Centre for Safe Air estimates particulate and NOx pollution from traffic leads to more than 1,800 earlier than expected deaths a year.

"Motor vehicles are one of the most important sources of air pollution in Australia," the Centre's director Fay Johnston said.

NO2 is a reddish-brownish gas with an acrid odour, while NO is colourless and odourless.

A near-invisible haze of NOx spreads outwards from highways and suburban streets. Levels drop at about 100 metres to 200m from the source, but remain high in busy traffic areas.

Breathed in, long-term exposure to NOx can damage the lungs and lead to diseases like bronchitis and asthma. It generally inflames and stresses cells in the body, which is linked with heart disease.

"We can measure the increased rates of deaths when NOx pollution is higher," Professor Johnston said.

Despite this high public health impact, Australia has delayed tightening vehicle NOx pollution regulations and is now about a decade behind Europe, the UK and the US.

The AAA's results show a 2024 Toyota LandCruiser Prado (GXL) diesel and a 2024 Mitsubishi Pajero Sport (GSR) diesel have very similar fuel consumption and CO2 emissions.

But the Pajero's NOx emissions are about 17 times higher than the Land Cruiser's.

The reason for this is "after treatment", or the process of cleaning exhaust gases after they come out of the engine.

The most effective method is to inject a nitrogen-rich additive, like AdBlue, into the hot exhaust gases, which converts the NOx into nitrogen gas (N2), water (H2O) and CO2. This is known as selective catalytic reduction (SCR).

The 2022 Toyota Land Cruiser Prado uses SCR, while the 2024 Mitsubishi Pajero Sport does not.

SCR is so effective that it can make a diesel emit as much NOx as a petrol car — and even less than some petrol cars.

Essentially all diesels now sold in Europe use SCR to comply with emissions standards, Shawn Kook, director of the UNSW engine research laboratory, said.

Europe's had these standards since 2015. 

"The technology and products are there," Professor Kook said.

"It is just that [adding this technology] will add costs to car makers."

AdBlue is stocked at petrol stations around Australia. (Getty: John Keeble)

1800 dead per year!  Imagine if it was terrorists or murders!  Over the last 12 months, there were 1361 road deaths in Australia.   There were 227 murders.   

GWR's battery-electric train--the verdict

 I talked about this before.  This new video gives more useful detail.

• GWR has been investigating battery-electric trains to replace diesel on branch lines.
• Straight-out electrification is expensive.  The overhead wires and the catenary posts are costly.  On high-volume routes, this cost is worth it. But on less-used lines it is not.
• On this route, the diesel train produces 960 kg of carbon dioxide vs 235 kg per day for the battery units (a 75% reduction)  With renewable energy sources for the electricity, this could be reduced to 26 kg/day (a 97% reduction)
• The charging rail is on the ground, but is only activated when the train is over it (much safer!)
• It reaches full charge in 4 minutes (for 5 miles of travel).  The charger is connected to a bank of batteries (on the ground) which is connected to the national grid.  This stops the massive drain of power from tripping the local grid.
• So, unlike an overhead-wire electrification, it's just one charging station, which means there is no need for catenary posts and adjacent electrical infrastructure.  It's all off-the-shelf equipment, and can be installed with ease, even while services are running.
• Even with current battery technology, the batteries only need to be swapped out once in the unit's operating life, and can then be recycled.
• It's been tested under all sorts of conditions: rain, ice, leaves on the line, snow and baking heat, with full heating on, and it's worked without problems.
• It's far more efficient than diesels in terms of power usage, with 79% efficiency, with an electricity consumption of 2.4 kW per carriage per mile, and is obviously much quieter than a diesel.
• Diesels are more expensive on fuel and maintenance, but were cheapest on infrastructure. Overhead electrification was most expensive on infrastructure, but on a par with battery-trains on other costs.  Costs per train-mile:  £5/ train-mile, diesels £4/train-mile, battery-trains £2.52/train-mile.
• The batteries have a possible range of at least 80 miles (130 km).  [Though, by my calculations, that would take an hour to charge].  It is possible, though less efficient, to charge the batteries via the overhead cable, i.e., this battery-electric train could run along mixed electrified and unelectrified track.

Land transport contributes +-20% to CO2 emissions, and more to NOx, which are much more potent greenhouse gases.  Cars and light trucks make up most of this, but diesel for rail is not insignificant.  And it's horribly polluting.   

See also my articles on battery-electric trains.

NO2 pollution plummets in Paris

 From Brent Toderian

Air pollution has dropped significantly in #Paris in the last 15 years. Mayor @annehidalgo.bsky.social’s leadership has traded car space for green space, safe bike space, kid space.. and traded pollution for people.

Good trade.

 

The best climate news

 I've mentioned this before.  

On February 17, CCNow held a joint press briefing with Scientific American on a little-known scientific development that carries paradigm-shifting implications for how people think and feel about the climate crisis and how governments and societies respond to it.

Most journalists have long echoed what we thought was the scientific consensus: Even if greenhouse gas emissions stop, global temperatures will keep rising for 30 to 40 more years, mainly because of carbon dioxide’s long lifetime in the atmosphere. But in fact the latest science doesn’t say that. The lag time for temperature rise would actually be as little as 3 to 5 years, as was noted in the latest IPCC report last August and explained in a Scientific American article last October.

The phrasing employed by the IPCC scientists is, unfortunately, not easy for non-scientists to decipher, but the following is a lay person’s guide. The key graph is the bottom of the two graphs in Figure 1.5, and the key sentence is the fourth sentence in the box of text to the right of that graph. That sentence reads: “Temperatures continue to increase slightly after the elimination of CO2 emissions (blue line) in response to constant non-CO2 forcing.” A more reader friendly way to phrase this would be—we’ve added emphasis and extra wording here with italics–“Temperatures continue to increase only slightly after the elimination of CO2 emissions (blue line)…” Here, “only slightly” refers to the 3 to 5 years of additional warming that Michael Mann cited, while “elimination” refers to the hypothetical case of humanity halting all greenhouse gas emissions overnight.

You can visualize this potential halt in temperature rise by looking at the solid blue line in the bottom of the two graphs, which proceeds in an almost perfectly straight line from left to right, depicting how temperatures would remain virtually flat out to the year 2100. Be careful to follow the solid blue line and not the dotted blue line or the dashed blue line, which depict radically different scenarios.

I thought the chart very useful.

Source: The Best Climate Science You’ve Never Heard Of

The top chart shows "forcing" in watts per square metre.  Forcing is the energy flux (how much energy accumulates, netting out the inflow (from the sun) and radiation from the earth.)  As forcing becomes more positive, global temperatures rise.  (Read the Wikipedia article for a more scientific definition and explanation.)  The temperatures on Earth rise and fall following radiative forcing, with a lag.    

The bottom chart shows the temperature, with the left axis the temperature change since 2020, and the right the temperature above pre-industrial averages.  The dashed blue line shows how temperatures will go on rising if the trend since 1980 (± 0.2 degrees C) continues.  The blue line (close to horizontal in the bottom chart, falling in the top) shows the temperature/forcing if we suddenly stopped emitting CO2, but kept on emitting methane (CH4)  and Nox (NO2).  The pink/purple line shows what would happen if we stopped emitting all greenhouse gases (mainly CO2, NO2 and CH4).  The green line shows the temperature (lower chart) and forcings (upper chart) if we stop emitting CO2 and also stop emitting aerosols.  Aerosols reflect incoming sunlight (including infra-red) back into space, so they reduce global warming.  The dotted line shows what happens with a 50-year phaseout of CO2 emissions, but all other forcings (CH4, NO2 and aerosols) constant.  A 50-year phaseout implies net-zero by 2070, not 2050.

The key points from this analysis are:

• If we stop emitting greenhouse gases, forcings stop rising within 3 to 5 years.  See how in the top chart, forcings jump sharply(green line) if we stop both CO2 and aerosols but not other GHGs, then declines steadily.   Temperatures jump (bottom chart) but then rise only slowly.
• If we stop all GHG emissions (CO2, NO2, CH4) but continue with aerosols, both forcings and temperatures peak immediately, and in fact temeratures start to fall, by about 0.4 degrees from 2020 levels.
• If we cut CO2 emissions to zero over the next 50 years, the rise in global temperatures since pre-industrial times is just a whisker over 1.5 degrees.

Some people will interpret this good news as meaning that we need take no action to cut emissions, that everything will be all right.  This is wrong. Look again at the dashed blue line.  If we take no action, temperatures will go on rising by 0.2 degrees a decade.   

The clear implication of this research is that the sooner we cut emissions, the sooner global temperatures will stop rising.  We won't have to wait decades for the global climate system to respond.  If we transition electricity generation to renewables and our vehicle fleet to electric engines, the world will be able to cut emissions by 50%.  We should do that as soon as possible.

Pollution makes Covid much worse

Dense smog in Milan.
The heavily polluted northern Italian city and the surrounding region have been hard hit by the coronavirus outbreak.
Photograph: Flavio Lo Scalzo/Reuters

There are three new reports linking air pollution with higher death rates from the coronavirus.

The first, from Climate News Network:

In research which could, if confirmed by further studies, have fundamental implications not only for health but also for the climate crisis, scientists at the University of Cambridge say they have found an association between living in parts of England with high levels of air pollution and Covid-19 severity.

Because of the urgent need to share information relating to the pandemic, the researchers say, they have decided to publish their report on medRxiv, the preprint server for health sciences, even though it has not yet been peer-reviewed. However, they say, this preliminary data is supported by that from other countries.

The initial symptoms of Covid-19 include fever, but do not always include breathing difficulties. But, the researchers point out, some patients do go on to develop very serious respiratory problems. Although most experience only mild illness, around a quarter of patients admitted to hospital need intensive care treatment because of viral pneumonia with respiratory complications.

Research suggests that this probably stems from an overactive immune response, they say − but it is not clear why some patients are at greater risk of severe disease.

Previous studies have suggested that people over the age of 60 or with underlying health conditions, including cardiovascular disease, diabetes, chronic respiratory disease and cancer, are at highest risk of severe disease or death.

Long-term exposure to air pollutants, including nitrogen oxides and ground-level ozone from car exhaust fumes or burning fossil fuels is a known risk factor for these health conditions.

Such pollutants can also cause a persistent inflammatory response and increase the risk of infection by viruses that target the respiratory tract.

[Read more here]

The other two are from The Guardian.

High levels of air pollution may be “one of the most important contributors” to deaths from Covid-19, according to research.

The analysis shows that of the coronavirus deaths across 66 administrative regions in Italy, Spain, France and Germany, 78% of them occurred in just five regions, and these were the most polluted.

The research examined levels of nitrogen dioxide, a pollutant produced mostly by diesel vehicles, and weather conditions that can prevent dirty air from dispersing away from a city. Many studies have linked NO2 exposure to health damage, and particularly lung disease, which could make people more likely to die if they contract Covid-19.

“The results indicate that long-term exposure to this pollutant may be one of the most important contributors to fatality caused by the Covid-19 virus in these regions and maybe across the whole world,” said Yaron Ogen, at Martin Luther University Halle-Wittenberg in Germany, who conducted the research. “Poisoning our environment means poisoning our own body, and when it experiences chronic respiratory stress its ability to defend itself from infections is limited.”

[Read more here]


And, coronavirus detected on particles of air pollution.

Coronavirus has been detected on particles of air pollution by scientists investigating whether this could enable it to be carried over longer distances and increase the number of people infected.

The work is preliminary and it is not yet known if the virus remains viable on pollution particles and in sufficient quantity to cause disease.

The Italian scientists used standard techniques to collect outdoor air pollution samples at one urban and one industrial site in Bergamo province and identified a gene highly specific to Covid-19 in multiple samples. The detection was confirmed by blind testing at an independent laboratory.

Previous studies have shown that air pollution particles do harbour microbes and that pollution is likely to have carried the viruses causing bird flu, measles and foot-and-mouth disease over considerable distances.

The potential role of air pollution particles is linked to the broader question of how the coronavirus is transmitted. Large virus-laden droplets from infected people’s coughs and sneezes fall to the ground within a metre or two. But much smaller droplets, less than 5 microns in diameter, can remain in the air for minutes to hours and travel further.

[Read more here]

What can we do about air pollution?  It's easy to think we have to wait for batteries to fall in cost so that we can use them to "firm" electricity generation and facilitate the switch to EVs.  Actually, batteries are falling in cost very fast.   Yet it is possible to cut emissions from electricity generation by 80%, even without using batteries, though batteries help, by providing overcapacity in renewables in a continent-wide grid with backup from gas-fired peaker plants.  I discuss this fully here.  Renewables are much cheaper than coal, so we'd actually save money. Plus, if we banned all cars without an electric motor, even if they are not full EVs, but hybrids (HEVs) or plug-in hybrids (PHEVs), we could cut emissions from transport by 50% to 80%.   And with steel, we can also reduce emissions by using green hydrogen or green methane instead of coking coal.

If we wanted to, we could cut the worst air pollution (from petrol/diesel engines) by 25% over the next five years, and 50% over the next 10, just by banning the sale of new cars without electric engines.  Car prices would rise by only $1500-$2000.  The average car lasts 10 years,  but the switch could be accelerated by  a "cash for clunkers" program.  Plug in hybrids (PHEVs) cost around $5000 more than petrol cars, but they cut emissions and pollution by 80%.   A tax incentive of $2000 per car will make HEVs as cheap as petrol cars, and PHEVs only $3000 more expensive.  Since petrol consumption will be much reduced, these higher costs will be offset by reduced fuel charges.  Actually, we can cut emissions by even more, because in 10 years' time, batteries will cost 10% of what they do now, and PHEVs and full EVs will be concomitantly cheaper.

The question is, do we really want to cut air pollution?  Or are we going to go on listening to the urgent entreaties of legacy car makers who have dragged their feet in this transition?  Are we going to force a shift in electricity generation away from coal, or are we going to continue to phiff and phaff?  Are we going to introduce a carbon tax to encourage iron and steel and cement producers to reduce emissions?

It's up to us.  There are no technological and only small cost impediments to us doing these things.  Only politics and corruption stop us.

Pollution falls over NE United States

Thanks to the lockdown, nitrogen dioxide pollution has fallen over the NE USA to the lowest level since 2005.  (Report from Space.com)

Notice how bad the pollution is around New York.  There is a reason why the death toll there has been so appalling: air pollution dramatically increases the death rate from the coronavirus.  As the Australian government says:

The main effect of breathing in raised levels of nitrogen dioxide is the increased likelihood of respiratory problems. Nitrogen dioxide inflames the lining of the lungs, and it can reduce immunity to lung infections. This can cause problems such as wheezing, coughing, colds, flu and bronchitis.

And it can triple or quadruple the death rate from coronavirus.

We could significantly reduce NO2 air pollution (which comes mostly from cars, lorries and buses) just by mandating that all new cars sold must have an electric engine.  They don't have to be full-on EVs.  Even an "old-fashioned" hybrid (HEV) uses 40-50% less petrol (gasoline) than a conventional (ICE) car.  A plug-in hybrid (PHEV) is even more efficient.  It depends on the car and the kind of driving you do, but the Chevrolet Volt can get more than 100 m.p.g. (2.4 litres/100 km), in some cases as high as 150 m.p.g.  The average car in the US achieves 24.9 m.p.g. (9.4 litres/100 km)    This suggests that PHEVs could cut emissions 75%, or more if their batteries allow for a 30 miles plus electric range.

We could ban the sales of ICEVs tomorrow, and sweeten the deal with a $1500 cashback if you buy any car with an electric engine.  And within 5 years we would have cut lethal NO2 by 50%.

See also:

Toyota's biggest selling hybrid isn't the Prius

The EV bridge

The hybrid solution

Cutting car emissions by 50%. Cheaply & cleanly