Smart Cities - Air Pollution

• Particulate matter (PM) is an air pollutant consisting of a mixture of solid and liquid particles suspended in the air.
• PM can either be directly emitted into the air (primary PM) or be formed in the atmosphere from gaseous precursors (mainly sulphur dioxide, nitrogen oxides, ammonia and non-methane volatile organic compounds [NMVOCs]).
• Primary PM and the precursor gases can have anthropogenic and nonanthropogenic sources.
• Commonly used indicators describing PM refer to the mass concentration of PM10 (particles with a diameter <10 μm) and PM2.5 (particles with a diameter <2.5 μm). Part of PM2.5 and PM10 comprises ultrafine particles with a diameter <0.1 μm.
• PM between 0.1 μm and 1 μm in diameter can remain in the atmosphere for days or weeks and thus be subject to long-range cross-border transportation.
• The most important chemical constituents of PM are sulphates, nitrates, ammonium, other inorganic ions such as Na+, K+, Ca²⁺, Mg²⁺ and Cl–, organic and elemental carbon, crustal material, particle-bound water and heavy metals.

Although official efforts to control air pollution have traditionally focused on outdoor air, it is now apparent that elevated contaminant concentrations are common inside some private and public buildings.

Concerns about potential public health problems due to indoor air pollution are based on evidence that urban residents typically spend more than 90 percent of their time indoors, concentrations of some contaminants are higher indoors than outdoors, and for some pollutants personal exposures are not adequately characterised by outdoor measurements.

Among the more important indoor contaminants associated with health or irritation effects are passive tobacco smoke, radon decay products, carbon monoxide, nitrogen dioxide, formaldehyde, asbestos fibres, micro-organisms, and aero-allergens.

Efforts to assess health risks associated with indoor air pollution are limited by insufficient information about the number of people exposed, the pattern and severity of exposures, and the health consequences of exposures. An overall strategy should be developed to investigate indoor exposures, health effects, control options, and public policy alternatives ^[5], ^[6].

The following databases provide graphical representation:

Our World in Data, with a database for greenhouse gas
Global Carbon Atlas, with a database for CO₂ emissions

Teachers can look for data from their own country. Every country profile in Our World in Data includes five sections.

1. CO₂ emissions: How much does a country emit each year? What are the average emissions per person? How much has the country emitted over time? How do emissions for a country compare when we correct for traded goods?
2. Coal, oil, gas, cement: How much CO₂ comes from coal, oil, gas, flaring or cement production?
3. Other greenhouse gases: What are the total greenhouse gases emitted by each country? How much methane, and nitrous oxide is emitted?
4. Emissions by sector: Which sectors contribute most to emissions? Does transport contribute more or less than electricity? How large are agriculture and land use emissions?
5. Carbon and energy efficiency: How much energy do we use per unit of GDP? How much carbon do we emit per unit of energy?

Modern research has shown that a new biofuel made from wood helps reduce carbon dioxide emissions. In fact, some companies have dedicated themselves to the sustainable management of forests for the production of the first such biofuel.

• Carbon dioxide emissions in Greece increased every year until 2008 and since then they have been decreasing until today.
• The change in carbon dioxide emissions each year is about 4% down from 2008 to date.

From the map of world CO₂ emissions, we observe that Greece is ranked 51st in the world ranking (in 2019), while the first place is held by China, followed by the USA and then India and Russia.

The peak of annual CO₂ emissions is observed in 2007 (114.59 million tonnes), while the peak of emissions based on consumption is observed in 2002 (112.23 million tonnes).

Between the years 2002-2003, 2008-2009 and 2010, the annual emissions are almost equal to the emissions based on consumption.

From the graph you can see that between 1990 and 2002, consumption-based emissions increased (around 16.6% increase) and were higher than annual emissions. Between 2002 and 2009 there is a decline and then a return of emissions based on consumption. From 2010 onwards there is not only a vertical decrease (approximately 73.7% decrease), but they are also higher than annual emissions. This means that production is higher than consumption.

• From 1949 to 2017 emissions per person increased by 6.75 tonnes (from 0.11 tonnes to 6.86 tonnes, i.e. by 6136%).
• From 2001 to 2011 emissions per person increased by 4.18 tonnes (from 2.64 tonnes to 6.82 tonnes, i.e. by 158% each year (on average) this decade).
• From 2011 to 2017 CO₂ emissions increased by only 0.2 tonnes per person, while total emissions are around 10 billion tonnes per year.
• Research question: what is the reason for the rapid increase in CO₂ emissions in the decade 2001 - 2011 and where is their stabilisation in the next decade?

From 1978 onwards, China increasingly began to promote industrialisation and urbanisation. This rapid industrialisation, which peaked at the beginning of the 21st century, was the reason why carbon dioxide emissions increased with devastating consequences for the country.

Over the past decade, humanity has begun to pay attention to environmental protection, so China has taken steps to stabilise its emissions under pressure from a large number of developed countries. In fact, in the Copenhagen pact on climate change of 18th December 2009, China set the ambitious goal of reducing CO₂ emissions by 40-45% by 2020, which unfortunately was not achieved even by a small percentage ^[7] .

Selected countries: Spain, Portugal, Greece, Germany, Ghana

Country selection criteria: Spain and Portugal are neighbouring countries, so it would be interesting to see if and what the differences are. Greece is a Mediterranean country like the previous two, but not their neighbour and much smaller in size. Germany is a large country, known for its economies of scale and technological development / activity. Finally, Ghana is a developing country, so it would be interesting to study the environmental impact of a country of this industrial scale.

Chart study period: 1800-2020

Teachers ask students to use an online calculator (e.g. UN carbon footprint calculator, carbon footprint calculator) in order to estimate their impact on global warming over a period of 12 months.

They can select their daily habits:

1. Amount of total energy used in the house
2. Flight itineraries
3. Transportation (car, motorbike, bus and rail)
4. Food and drink products, computer and IT components etc.

To conclude, the students can research ideas on how to reduce their carbon footprint.

1. Air Quality Databases

2. Carbon footprint calculator