How Pollutants Can Affect Human Health

Relationships between exposure to pollutants and the consequent health effects have been
extensively researched over several decades and have resulted in the introduction of numerous
standards, targets and guidelines aimed at minimising risk at both local and regional levels.
The success of these measures continues to be very mixed. In some regions considerable
progress has been made to introduce cleaner fuels and reduce overall emissions from transport
vehicles and industry. In most cases this has resulted in a beneficial impact on air quality.
Other parts of the world still face an uphill battle, and may be held back by a number of factors
including poverty, reliance on dirty energy sources, broad-acre burning or ineffectual government
administration.
The interactions between airborne pollutants and human health are complex and are influenced
by exposure levels, duration of exposure and the inherent toxicity of individual pollutants. In
many situations the youngest and oldest sections of the population are most vulnerable.
An unavoidable consequence of global population growth has been increased urbanisation.
Regardless of how rich or how poor the cities might be, high population densities result in a
commensurately higher incidence of sickness from air pollution. In many cities, a combination of
high polluting vehicles, street cooking and proximity of heavy industry can take a heavy toll.
But wealthier regions are not immune to the problems. The cost of providing health care, social
services and the direct economic cost of lost productivity can impact on a region’s economy to the
tune of tens or even hundreds of billions of dollars annually.
In regions where income levels and national budgets are much lower, many decisions are driven
by necessity rather than choice, and often these decisions can have a serious health downside.
Exposure to a cocktail of particles and toxic chemicals,
generated when wood or other biomass material is
used for indoor cooking, is responsible for widespread
sickness and greatly reduced life expectancy for many
people living in poorer communities.
Approximately one half of the world's population relies
on burning biomass, that is wood, crop residues, dung,
and charcoal, as their primary source of domestic
energy.
Exposure to indoor air pollution resulting from biomass
burning is the cause of widespread respiratory and eye infections. Putting this into perspective,
respiratory infections account for over 10% of the total disease burden in developing countries,
leading to an estimated 1.6 million deaths annually in these countries.
Programs aimed at improving food supply and medical care are of paramount importance, but the
value of practical measures to support and encourage healthier cooking practices should not be
overlooked. Switching to a simple, clean LP Gas burner can go a long way towards avoiding the
tragedy of an incapacitated parent, a chronically ill child, or worse, and should be an important
consideration for aid agencies and government assistance programs.

3.1 Health Effects of Individual Pollutants
This section briefly reviews the six most prevalent pollutants generated by commonly used fuels.
It should be noted that several fuels do not emit all of these pollutants, either through their
removal from the fuel (for example the addition of lead to gasoline is no longer permitted in most
countries), or because of the intrinsically clean composition of the fuel (for example LP Gas
contains no lead and very limited amount of sulphur compounds).
3.1.1 Which Pollutants are Most Important?
Literally hundreds of pollutants have potential to damage human health, but the United States
Environmental Protection Agency (EPA) has identified six pollutants, referred to as "criteria
pollutants" as being the highest priority. Standards for the criteria pollutants are regulated under
the Clean Air Act. The pollutants are:
• particulate matter (PM)
• nitrogen oxides (NOx)
• hydrocarbons (HC)
• carbon monoxide (CO)
• sulphur oxides (SOx)
• ground-level ozone (O3)
• lead (Pb)
Because of their role in the formation of ground level ozone, volatile organic compounds (VOCs)
are also widely regulated. Many dangerous compounds classed as “air toxics” are also
categorised as VOCs (see Section 3.1.9). VOCs are also often referred to simply as hydrocarbons
(HC).
Most countries recognise the same pollutants as being the highest priority health related
pollutants in their regulations and emission abatement programs.
There are still some highly populated regions where fuels with high sulphur and/or lead contents
continue to be sold.
In addition to the criteria pollutants listed above, another very large and important group of
hazardous chemicals (generally referred to as “air toxics”) are released to the atmosphere during
combustion of most fuels. The more significant of these pollutants are discussed briefly in Section
3.1.9, with more detailed information in Annex A1.
3.1.2 Particulate Matter (PM)
Particulate matter (PM) from fuel combustion is a mixture of solid particles and liquid droplets
suspended in the air. A high proportion of these particles are extremely small, mostly less than 10
microns (about 10 times smaller than the thickness of a human hair). The smallest particles can
go down to 10 nanometers (one nanometer is one millionth of a millimetre or 0.000001mm) in
diameter), which is around 10,000 times smaller than the thickness of a human hair.
Particulate Matter is probably the most dangerous of all fuel-related pollutants because of its
known toxicity and the high exposure levels experienced by large sections of the world’s
population. It is emitted directly as a product of combustion from virtually every burning process,
though the rate at which it is emitted by different fuels can vary by a factor of 100 or more.
Gaseous products of combustion can also form into particles through chemical reactions in the
atmosphere.

From a regulatory perspective, transport sources of PM emissions have received most attention,
but it is likely that other sources generate comparable or even higher atmospheric particle
concentrations in some regions or localised instances. Some of these include: wood-fire cooking,
coal-fired industrial processes, electricity generation, vegetation and naturally occurring wildfires.
Combustion-generated particles range in size
from ten microns or more, down to a few
nanometers. As can be seen in Figure 3.1, the
smaller particles can reach the deepest and
most sensitive areas of the lung. Those in the
nanometer range may even pass through the
lung tissue directly into the bloodstream. Over
90% of particles in the exhaust of internal
combustion engines are smaller than one
micron (PM1.0), ranging down to as little as 10
nanometers (0.00001mm).
In 1998 the California Air Resources Board
(CARB) determined diesel particulates to be a
Toxic Air Contaminant. In 2002, after much
research, the US EPA concluded that PM in
diesel exhaust causes acute throat and bronchial
irritation, poses a chronic respiratory hazard to
humans, and is a likely carcinogen. Particles may
also adsorb potentially health-threatening organic
“air toxics” found in engine exhaust.
Gasoline and diesel exhaust particles pose a higher risk than those of LP Gas, as not only do these
fuels generate higher particle concentrations, but the exhaust from liquid fuelled vehicles
contains much higher levels of air toxics, which can be adsorbed onto the surface of particles and
carried into the most sensitive lung areas.
This can lead to severe lung problems and increased susceptibility to respiratory infection, such as
pneumonia, aggravation of acute and chronic bronchitis, and asthma. Moreover, the very
smallest particles can even pass through the lung tissue directly into the bloodstream, where they
have been linked to a number of neurological and heart disorders.
There are large differences between the particle emissions associated with different fuels. Diesel
engines and burning of wood and other biomass materials generate the highest levels of PM.
Gaseous fuels, notably LP Gas, have the lowest emissions of this pollutant.
3.1.3 Nitrogen Oxides (NOx)
Several oxides of nitrogen, all of which can be produced in fuel combustion, have significant
environmental and health impacts. The principal compounds of concern are nitrogen dioxide
(NO2), nitrous oxide (N2O) and nitric oxide (NO). Collectively these compounds are referred to
simply as NOx.
Photochemical smog is formed when NOx and volatile organic compounds (VOCs) react in the
presence of sunlight to form ozone. Smog severely irritates the mucous membranes of the nose
and throat, which can lead to coughing and even choking. It also impairs normal functioning of the
lungs and long-term exposure may cause permanent damage. Ozone can also reduce crop yields
NOx and sulphur dioxide react with other substances in the air to form acids which can fall to
earth as “acid rain”, damaging property and, in some areas causing lakes and streams to become
sterile. Through a reaction with ammonia or other compounds NOx can be transformed from a gas into tiny nitric acid particles which, when inhaled can affect breathing, damage lung tissue,
and even lead to premature death.
Nitrous oxide (N2O) is a very powerful greenhouse gas. Its influence as a greenhouse gas is more
than 298 times greater than carbon dioxide (CO2), but fortunately is generally produced in
relatively small amounts. There is concern that chemical reactions in the catalytic converters
fitted to motor vehicles to reduce other pollutants emissions may in fact increase emissions of
N2O.
3.1.4 Hydrocarbons (HC) (also referred to as Volatile Organic Compounds (VOC)
Hydrocarbons are compounds containing only hydrogen and carbon atoms. They are present in
the air both as naturally occurring gases and as the product of incomplete combustion of carbonbased
fuels. As well as being emitted during combustion, hydrocarbons are also released to the
atmosphere through evaporation from paints and solvents, industrial processes, and from
gasoline fuelled vehicles during refuelling or through failures in their on-board vapour recovery
systems.
They comprise a large range of gaseous organic compounds, many with complex chemical
structures, which react with NOx in the presence of sunlight to form ground level ozone – a
precursor of photochemical smog.
A number of hydrocarbon compounds, classified as “air toxics” are extremely hazardous to
humans, but are only generated in very small quantities from motor vehicles.
Some air toxics are known to be carcinogenic and this group of chemicals is also suspected to play
a role in the rapid growth of a number of “20th century” illnesses, including asthma. However,
because their ambient concentrations are extremely low, it has not yet been possible to reliably
establish dose response characteristics, nor to place a direct monetary cost on their exposure
effects (see Section 3.1.9).
3.1.5 Ozone (O3)
Ozone is a gas simply composed of three oxygen atoms. It is not usually emitted directly into the
air, but at ground-level is created by a chemical reaction between oxides of nitrogen (NOx) and
volatile organic compounds (VOCs) in the presence of sunlight. Motor vehicle exhaust and
industrial emissions, gasoline vapours, and chemical solvents as well as natural sources emit NOx
and VOCs that help form ozone, which is the primary constituent of photochemical smog.
From a health perspective, ozone is linked to a number of respiratory illnesses including airway
irritation, aggravation of asthma, increased susceptibility to respiratory illnesses like pneumonia
and bronchitis; and permanent lung damage with repeated exposures.
Ozone also damages vegetation and ecosystems. In the United States alone, it is responsible for
an estimated US$500 million in reduced crop production each year.
3.1.6 Carbon Monoxide (CO)
Carbon Monoxide (CO) is a colourless, odourless, poisonous gas composed of one atom each of
carbon and oxygen. It is formed when carbon-based fuel is not burned completely.
When inhaled, CO enters the bloodstream, where it binds chemically to haemoglobin, which
normally carries oxygen to the cells, and reduces oxygen delivery to all tissues. Even at relatively
low concentrations, CO can adversely affect mental function, visual acuity, and alertness. At
higher concentrations exposure can be fatal.
3.1.7 Sulphur Dioxide (SO2)
dioxide causes a wide variety of health and environmental impacts because of the way it
reacts with other substances in the air. Particularly sensitive groups include people with asthma
who are active outdoors and children, the elderly, and people with heart or lung disease. Peak
levels of sulphur dioxide air can cause temporary breathing difficulty for people with asthma who
are active outdoors. Longer-term exposures to high levels of sulphur dioxide gas and particles
cause respiratory illness and aggravate existing heart disease.
Sulphur dioxide also reacts with other chemicals in the air to form tiny sulphate particles. When
these are inhaled, they gather in the lungs and are associated with increased respiratory
symptoms and disease, difficulty in breathing, and even premature death.
When sulphur dioxide and nitrogen oxides react with other substances in the air they can form
acids, which fall to earth as rain, fog, snow, or dry particles – this phenomenon is commonly
described as “acid rain”, which may be carried by the wind for hundreds of kilometres.
Acid rain damages forests and crops, changes the makeup of soil, and makes lakes and streams
acidic and unsuitable for fish. Continued exposure over a long time changes the natural variety of
plants and animals in an ecosystem.
LP Gas emits little or no sulphur dioxide. It is the ideal energy source to replace many of the
sulphur-bearing fuels still in use, particularly wood-burning heaters and many industrial process
heat sources.
Other issues relating to the sulphur content of fuels are addressed in Technical Appendix A1.
3.1.8 Which Fuels?
The mix of pollutants and their relative emission rates can vary considerably between individual
fuels. This document focuses on the most widely available energy sources in general use for
cooking, heating, power generation and transport. These are:
• gasoline
• diesel
• liquefied petroleum gas [LP Gas]
• natural gas (methane) [NG]
• coal
• charcoal
• wood and related biomass
While many of these fuels have quite different physical characteristics, they are all related insofar
as their basic chemical structure consists almost entirely of carbon and hydrogen.
The first four fuels in the above list are of fossil origin, created over millions of years from the
remains of organisms that settled to the sea bottom and were buried under heavy layers of
sediment. The resultant heat and pressure has caused the organic matter to be transformed into
liquid and gaseous hydrocarbons, which can be recovered by drilling through the sedimentary
layers. LP Gas and Methane are often recovered from the same well, and both gases share many
health-related benefits.
Coal, on the other hand, is formed from land-based vegetation and tends to be found close to the
earth’s surface. Methane, commercially marketed as "natural gas", is often present in coal seams,
in addition to being found in the fossil fuel strata.
The last three items on the list either consist of, or are directly derived from, surface vegetation
(biomass).Methane is also generated through short-term decomposition of vegetation and waste. As such,
it can be captured at land-fill and similar sites, then stored and distributed. Methane produced in
this way represents only a very small fraction of total consumption.
3.1.9 Air Toxic Compounds
In addition to the criteria pollutants, there is a long list of "air toxic" compounds, some of which
are designated as carcinogens; others can have serious effects on human neurological and
reproductive systems. The US EPA classifies 187 compounds as “hazardous air pollutants”.
Although these compounds are mostly emitted in very small quantities and hence their health
impacts are sometimes difficult to establish at the dosage rates typically encountered, they are
nevertheless considered sufficiently dangerous to be monitored and, where possible, human
exposure minimised. The EPA estimates that mobile (car, truck, and bus, etc) sources of air toxics
account for as much as half of all cancers attributed to outdoor sources of air toxics (US EPA
1994).
Virtually all fuels produce some of these dangerous compounds when burned, but there are large
differences in emission levels between individual fuels. Gasoline tends to have high air toxic
emissions while LP Gas has the lowest, primarily due to its extremely simple chemical structure
which promotes very clean and complete burning. To illustrate this, Figure 3.2 compares relative
levels of typical motor vehicle engine-out emissions (with petrol = 100 as a reference) of some key
air toxics for the most widely available commercial fuels (Anyon, 2002), based on data from an
Argonne National Laboratory report (Winebrake J., 2000).
Note: CURE = Cancer Unit Risk Estimate, defined as “the upper-bound excess lifetime cancer risk
estimated to result from continuous exposure to an agent (e.g. chemical) at a concentration of 1
microgram per cubic metre in air or 1 microgram per litre in water”. Hence the higher the CURE
number, the higher the human cancer risk.
Table 3.3 (below) is based on Australian Government data (NPI 2000) and also highlights the
extremely low air toxic emission levels from LP Gas fuelled vehicles, compared with gasoline and
diesel equivalents.
Air Toxic Emissions, Passenger Car Exhaust (g/km)
By Road Type
Road Type: Arterial Freeway Residential
Benzene
Gasoline 0.08291 0.08817 0.09541
Diesel 0.00334 0.00313 0.00518
LP Gas 0.00001 0.00001 0.00002
1,3-butadiene
Gasoline 0.01064 0.00993 0.01642
Diesel 0.00064 0.00059 0.00099
LP Gas 0.00010 0.00009 0.00015
PAHs
Gasoline 0.00668 0.00625 0.01035
Diesel 0.00674 0.00628 0.01041
LP Gas 0.00000 0.00000 0.00000
Toluene
Gasoline 0.05618 0.02531 0.05618
Diesel 0.01573 0.00710 0.01573
LP Gas 0.00000 0.00000 0.00000
Gasoline 0.08880 0.04175 0.08880
Diesel 0.03405 0.02516 0.03405
LP Gas 0.00000 0.00000 0.00000
Table 3.3: Passenger Car Air Toxic Emissions by Fuel and Road Type (NPI 2000)
For a more comprehensive discussion of regulated pollutants and air toxic substances please refer
to Annexes A1 in this document.
4 Quantifying Health Impacts
4.1 Background
Attributing monetary values to human sickness and death is a sensitive and sometimes
contentious issue. From a purely academic standpoint it is certainly possible to draw together the
monetary costs associated with a range of factors associated with, or directly resulting from a
person's illness or death. But it can also be argued that from another perspective the social costs
are at least equally as important as simply adding up the dollars.
Logically, economic analysis of pollution health is influenced by the financial circumstances of the
persons involved and of the society they live in. Hence these analyses tend to focus on:
• average income levels for the region under consideration and the loss of household
income attributable to illness or death;
• the cost of providing hospitalisation and medical services;
• the cost of providing social services and support consequential to the illness or death of
an individual;
• the value of lost productivity due to a person's inability to contribute to the economy; and
• estimates of the community's "willingness to pay" to avoid a premature death.
Apart from the last item, most of these factors can be analysed using well researched data and a
rational monetary figure, relevant to the general economy of the region being considered, can be
applied.
However, once we move away from the relatively orderly socio-economics of the developed
world, many of the above factors become irrelevant. In remote areas of developing countries, for
most of the population simply surviving from one day to the next becomes the whole focus of life.
In a subsistence society, income levels are often
close to zero. Medical attention and access to
hospital services are most likely difficult to obtain, or
even close to non-existent. Loss of productivity is
not measured in Dollars or Euros, but rather the
ability of a person to contribute to the community by
gathering and preparing food, growing crops or
husbanding animals.
So, using the measures applied to inhabitants of a
developed economy, the value of a life in a poor
society would be extremely low. But of course this is
not the case. The life and well-being of a family or friend is just as valuable to members of a money-poor society as it is to the most wealthy city
dwellers.
But there is common ground when we focus only on health impacts, where the health
consequences of exposure to pollutants are principally determined by:
• exposure levels to the pollutants of concern (usually specified as a concentration in parts
per million or micrograms of pollutant per cubic metre of air); and
• the typical dose response (severity of health impact) for the exposure levels encountered.
This report therefore presents health impacts in monetary terms where the issue under
consideration is of a macro nature, such as quantifying the consequences of exposure to motor
vehicle pollution in urban areas. Where the issues are much more localised, the impacts will be
presented in terms of the health risks to individuals, without reference to monetary values.
Although no pollutants are considered unimportant, some are more important than others. In
most regions the greatest concern focuses on particulate matter (PM), oxides of nitrogen (NOx)
and volatile organic carbons (VOCs). Of these, PM generally rates are highest, as will be seen
when health cost impacts are reviewed in the next section.
A massive amount of research has been performed to link exposure levels to health impacts. The
huge variability in response of individuals to any given pollutant concentration, coupled with the
continuously varying levels of pollution concentration and the difficulties in achieving consistency
in diagnosis or severity of illness, there is always a degree of uncertainty in any numerical analysis.
Nevertheless, the techniques developed for Time-series studies involving very large numbers of
patients allow valid statistical relationships to be developed between dose level and dose
response. Table 4.1 (Künzli et al, 2000) estimates of relative risk of some specific health factors
being increased by a 10 μg per cubic metre increase in exposure to particles with a size of 10
microns or less (PM10). This study on which this table is based covered residents of Austria,
France and Switzerland. (Note: The figure in the middle column is a multiplier, meaning that each
10μg/m3 increase in PM10 will increase the current risk by that factor. For example in the first line
the current risk level will be multiplied by 1.043 for each 10μg/m3 increase in PM10 exposure).
Health Outcome
Relative Risk Estimate Associated
with a 10 μg/m3 Increase in
PM10
95% Confidence Interval
Mortality (adults >30 years,
excluding violent deaths) 1.043 1.026-1.061
Respiratory hospital admissions
(all ages)
1.013 1.001-1.025
Cardiovascular hospital
admissions (all ages)
1.013 1.007-1.019
Chronic bronchitis incidence
(adults >25 years) 1.098 1.009-1.194
Bronchitis episodes (children
<15>20 years)
1.094 1.079-1.502
Asthma attacks (children <15>15 1.039 1.019-1.059

years)
Table 4.1: Risk estimates for 10 μg/m3 increase in PM10 used in (Künzli et al, 2000).
Even short-term exposure to PM can have serious health consequences. In 2005 the World
Health Organisation issued a publication summarising several years research into daily changes in
PM concentrations and their associated health outcomes. The report on which the WHO
publication was based (Anderson H et al, 2004) concluded that short-term changes in PM at all
levels can lead to inflammatory reactions in the lung, respiratory symptoms, adverse effects on
the cardiovascular system and increases in medication use, hospital admissions and mortality.
These findings are summarised in table 4.2 below. (Note: The figure in the middle column of
table 4.2 is, in this case, a percentage increase in the incidence of these outcomes for each
incremental 10μg/m3 increase in PM10 exposure.)
Health Outcome
Estimated Percentage
Increase in Risk per 10
μg/m3 of PM10
95% Confidence Interval
All-cause mortality 0.6 0.4-0.8
Mortality from respiratory diseases 1.3 0.5-2.0
Mortality from cardiovascular diseases 0.9 0.5-1.3
Hospital admissions for respiratory
disease, people age 65 years and over.
0.7 0.2-1.3
Table 4.2: Risk estimates for 10 μg/m3 increase in PM10 used in (Künzli et al, 2000).
4.2 Health Cost Impacts
As noted earlier, quantifying the cost of illness and premature death from exposure to pollution
involves estimating exposure levels and dose response, then linking the calculated health-related
consequences to the monetary value of medical care, social services, foregone income and the
cost of lost productivity. Most estimates of health cost impacts also include an amount
representing societies "willingness to pay" to avoid premature death.
It falls outside the scope of this report to enter into detailed discussion on methodologies and
rationale used in the many studies which have been performed to link pollution with financial
cost. Instead, we will review the range of estimates which have been put forward in relation to
the key air pollutants generated by commonly used fuels. These estimates vary considerably,
with some clearly underestimating and some probably over-estimating the net costs to society.
Nevertheless, it should be noted that aggregate health cost impacts are not based solely on
ambient exposure levels. Two key factors which come into play are:
• population density (for a given pollutant concentration, doubling the number of people in
a given area doubles the overall health cost impact)
• Gross Domestic Product (GDP) on a per capita basis, as this is a general measure of
prosperity, income levels and the cost of medical and social services in a region.
For convenience the monetary value attributed to individual pollutants is usually expressed as
Euros (or dollars etc) per tonne. This approach is very useful because it allows analysis of
scenarios based on the number of sources contributing to overall pollutant concentration levels importantly, how pollutant levels can be changed through measures to reduce emissions
from individual sources or to reduce the actual number of sources in a given area.
For instance, authorities may wish to explore the value of switching to cleaner fuels standards, or
using intrinsically cleaner fuels, or requiring equipment to meet more stringent emission
performance standards.
Table 4.3, extracted from a report prepared for the European Commission (Holland et al, 2005),
summarises average damage costs (€ per tonne) for the most significant regulated pollutants in all
the mainland European Union economies. Please note that the costs include estimated damage
to crops, in addition to human health impacts. However, the monetary value of crop damage is
only a very small proportion of the total (typically less than 5%) and so the values in the table may
be assumed to be closely indicative of estimated health costs.
Pollutant Health Cost (€ per tonne) – European Nations
Pollutants: PM2.5 NOx VOCs
Austria €110,000 €24,000 €5,200
Belgium €180,000 €14,000 €7,100
Czech Republic €91,000 €20,000 €3,000
Denmark €48,000 €12,100 €2,000
Estonia €12,000 €2,200 €420
Finland €16,000 €2,000 €490
France €130,000 €21,000 €4,200
Germany €140,000 €26,000 €5,100
Greece €25,000 €1,900 €880
Hungary €72,000 €15,000 €2,700
Ireland €42,000 €11,000 €2,000
Italy €97,000 €16,000 €3,500
Latvia €25,000 €3,700 €650
Lithuania €24,000 €5,000 €710
Luxembourg €120,000 €24,000 €8,000
Malta €27,000 €1,700 €1,300
Netherlands €180,000 €18,000 €5,400
Poland €83,000 €10,000 €1,900
Portugal €64,000 €3,200 €1,600
Slovakia €58,000 €14,000 €2,000
Slovenia €64,000 €18,000 €4,400
Spain €54,000 €7,200 €1,100
Sweden €34,000 €5,900 €980

United Kingdom €110,000 €10,000 €3,200
Table 4.3: Pollutant Health Costs (per tonne) for European Countries (Holland M et al 2005).
It should be noted that the above health cost estimates are, for each country, averaged across the
urban, provincial and rural regions of each country. Hence the distribution of population densities
across each country, together with the pollutant exposure levels in the different regions, result in
each country having differences in the relative costs attributed to each pollutant.
An example of the regional variations in health costs for a given country are illustrated in a report
(Rabl and Spadaro, 2000), which estimates pollution cost impacts representative of a car journey
from Paris to Lyon in France, a distance of 465km. This report takes account of the factors
outlined in the preceding paragraph and the aggregated health costs per tonne are summarised in
Table 4.4 below.
Pollutant Health Cost (€ / tonne)
PM2.5 160,000
SO2 10,000
NO2 15,700
VOC 700
CO 20
Table 4.4: Health damage costs per tonne of pollutant for trip from Paris to Lyon
The average country-wide health cost values are reasonably consistent with other published
reports, but it is interesting to note that the Rabl report also quantifies the differences between
urban and rural health impacts, which are estimated to be 14 times higher than the average for
travel in Paris, and about seven times lower for rural travel in the south-west of France.The results of the Rabl report underline the substantial added value of adopting low-polluting
energy sources in areas with high population densities.