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Auvergne Rhone Alpes is a state located in the southeastern region of France, with muchof its territory extending into the central areas as well. Its creation was theresult of the 2014 reformation of French territories, the result of the mergingtogether of Auvergne and Rhone Alpes. There are some 7.9 million inhabitantsstatewide, and its total area sum is close to 69,711km2, making it the third largest region in France.
Looking at the numbers when it comes to Auvergne Rhone Alpes air pollution levels, therewere a wide range of different PM2.5 readings across the state, with someconsiderable difference between the most and least polluted. Overall, it can beconsidered a clean state, with a year round good quality of air, free fromlarge volumes of pollution, although some cities do have year round ambientreadings that may be detrimental to certain demographics of the population,with months that go fairly high in terms of their PM2.5 readings, causingissues for sensitive groups such as the young, the elderly, the sick andimmunocompromised as well as those with preexisting illnesses and pregnant mothers.
PM2.5 refers to particulate matter that is 2.5 micrometers or less in diameter, making itapproximately 3% the size of a human hair, and with the potential to go down tomuch smaller sizes, as low as 0.001 or less. Thus, due to this incredibly smallsize it poses significant risks to human health, and although there are otherpollutants that are used in calculating the overall air quality, such asnitrogen or sulfur oxides and ozone (O3), PM2.5 will be the mainpollutant used to gauge the air quality levels in Auvergne Rhone Alpes.
To look at some tangible numbers, the most polluted city in the state over 2019 was LaMulatiere, coming in with a yearly average of 12.8 μg/m³, a reading that placedit into the ‘moderate’ pollution bracket, which requires a PM2.5 reading ofanywhere between 12.1 to 35.4 μg/m³ to be classified as such. For many of thecities statewide, there were certain months of the year that came in withreadings far in excess of this average, which will be discussed in short.
So as an overview, in 2019 one city came in with a moderate pollution rating, fourcities with a ‘good’ rating of air quality as their yearly average (10 to 12 μg/m³required), with the other 22 cities coming in within the World HealthOrganizations (WHO's) target goal of 0 to 10 μg/m³, for the best quality ofair. This shows that whilst there are many cities and months in the state thathave a very good quality of clean breathable air, there are still pollutive issues afflicting the region.
There are many different causes of pollution in Auvergne Rhone Alpes, that along withcompounding each other, can also be made worsened via accumulating, often dueto meteorological factors coupled in some cases with geographical ones. As anexample, a landlocked city surrounded by hills or mountains, or even highhumidity levels is far more likely to have greater accumulations of pollutionthan a coastal or high altitude town that is subject to heavy winds.
Pollution can be created and then retained, unable to disperse under certain circumstances, witheven the temperature playing a role, with the colder months seeing worse readings for several reasons.
One of the main causes of pollution in Auvergne Rhone Alpes would be that of vehicularfumes and emissions, with its millions of inhabitants travelling back and forthfor work, or to other cities, pushing up the ambient year round pollutionlevels through massive vehicular use.
Personal vehicles such as cars and motorbikes can populate the road, some of which willstill run on diesel fuels and thus release more potent types of pollution andin higher quantities. There are also the heavy duty vehicles to consider, thoseabove a certain weight class such as trucks, lorries and buses. These too mayalso run on diesel fuel and give off far more black soot and dangerous forms ofcarbon due to the combustion of fossil fuels.
Besides pollution caused by vehicles (which is even more prominent in areas near mainroads or motorways, as one would imagine), there would also be factory basedemissions, with factories and industrial areas often relying on coal to powertheir processes, as well as giving off whatever chemical effluence that is aresult of the product or items they are manufacturing (for example any factorythat recycles or creates plastic based products will inevitably give off some variety of plastic fumes).
Other sources of pollution would be the burning of organic material such as wood or otherdried plant matters, for heating stoves in traditional homes, mainly forproviding heat in the winter. The collective burning of this material wouldlead to a much larger reading of PM2.5 in the air due to all the various forms of carbon and other pollutants released.
Looking at the data taken over 2019, there start to be some patterns emerging that showwhen the most polluted times are, across all the different months and cities. Themonths that show up the most prominently and consistently with higher levels ofpollution are the winter months, with air quality starting to show a decline inOctober, and then November and December have significantly higher readings,which carries on into the next year, with January and February also showing higher readings.
March and April are also somewhat elevated in their readings, but not as prominently asthe last 4 months mentioned. During the winter months, far more indoor firesare burnt for the purpose of heating in stoves, very popular in low incomedistricts as well as more provincial areas outside of the big cities. Besidesthe burning of these materials, people also resort to turning up their heatingwhich in turn leads to higher amounts of energy being consumed, and factories working harder to produce this energy.
Over 60 percent of all cities in Auvergne Rhone Alpes followed this trend of higherpollution levels, and to use the city of Lyon as an example (being the secondmost polluted city in the state), in October its PM2.5 reading was 8.4 μg/m³. Thiswas followed by 12 μg/m³ in November, and then a further 18.7 μg/m³ inDecember. January also came in at 14,2 μg/m³, before reaching a high at 25.4 μg/m³in February, making it the most polluted month of the entire year for Lyon,with many other cities seeing the same pattern. Thus, the first two and lasttwo months of the year are when Auvergne Rhone Alpes pollution levels are at their worst.
Contrasting to the previous question, after the highly polluted winter months are over,there is a universal improvement in air quality levels through the middlemonths of the year, with the occasional abnormality in the most polluted cityof La Mulatiere, which had slightly raised readings in June and July, albeitconsiderably lower than its winter month readings, with numbers that came inwithin the ‘good’ rankings category of 10 to 12 μg/m³, and all the other monthssurrounding them such as May, August and September coming in within the WHO'starget goal, with readings of 8.2 μg/m³, 8.5 μg/m³ and 7.1 μg/m³ respectively.
This continues extensively for all cities in the state, with March through toOctober having large amounts of WHO target readings, meaning that AuvergneRhone Alpes air would be at its cleanest and most free from smoke, haze andsmog during the summer months of the year, more prominently so in cities nearto larger areas of greenery and vegetation such as Aurillac, further away from the larger and busier cities like Lyon.
With much of its pollution stemming from the use of cars, factory emissions and the burningof organic materials in homes and on people’s land or properties, thesubsequent pollution would all be related to the combustion of these various materials.
Some of the main ones released from vehicles would be nitrogen dioxide (NO2) andsulfur dioxide (SO2), with nitrogen dioxide being the most prominentpollutant when it comes to vehicular fumes, often being found in highquantities over areas that see larger volumes of traffic, so much so to thepoint that levels of nitrogen dioxide in the atmosphere can be used toaccurately determine how much pollution is coming from vehicles alone.
Other pollutants would include ozone, formed from the combination of various other compoundswhen subject to sunlight, and as such would be more prominent in the summermonths. Black carbon and volatile organic compounds (VOC's) would all bepresent, some of which would include dangerous chemicals like benzene, toluene,xylene, methylene chloride and formaldehyde. All of these are extremelydangerous to breath, and can come from factory emissions, as well as theburning of biomass and organic matter. Their volatile nature also makes themeasier to respire, due to them being gases at a lower temperature, increasingthe hazards associated with having such contaminants in the air.