Background

Air Pollution Worldwide

Air pollution is an important risk factor for health in Europe and worldwide. Air pollution levels remain dangerously high in many parts of the world. New data from WHO(World Health Organization) shows that 9 out of 10 people breathe air containing high levels of pollutants. A recent review of the global burden of disease revealed that it is one of the top ten risk factors for health globally. WHO also estimates that around 7 million people die every year from exposure to fine particles in polluted air that penetrate deep into the lungs and cardiovascular system, causing diseases including stroke, heart disease, lung cancer, chronic obstructive pulmonary diseases and respiratory infections, including pneumonia.

Outdoor air pollution originates from natural and anthropogenic sources. While natural sources contribute substantially to local air pollution in arid regions more prone to forest fires and dust storms, the contribution from human activities far exceeds natural sources. Human activities that are major sources of outdoor air pollution, include:

Fuel combustion from motor vehicles (e.g. cars and heavy duty vehicles)
Heat and power generation (e.g. oil and coal power plants and boilers)
Industrial facilities (e.g. manufacturing factories, mines, and oil refineries)
Municipal and agricultural waste sites and waste incineration/burning
Residential cooking, heating, and lighting with polluting fuels
Poor urban planning, which leads to sprawl and over-dependence on private vehicle transport

PM2.5 and PM10

The pollutants with the strongest evidence of health effects are particulate matter(PM),it is a complex mixture of extremely small airborne particles and liquid droplets. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope.

Particle pollution is a mixture of solid particles and liquid droplets. EPA(Environmental Protection Agency) monitors the air for two categories of particle size: PM2.5 and PM10. These particles are measured in micrometres (µm).

Health effects of PM2.5 particles

PM2.5 particles are small enough to be breathed deep into the lungs. This can cause health effects. Children, people over 65, pregnant women and people with existing heart or lung conditions (including asthma) are more sensitive to the effects of breathing in fine particles. Symptoms may include wheezing, chest tightness and difficulty breathing.

Sources of PM2.5 particles

PM2.5 particles result from the burning of fossil fuels (such as coal), organic matter (including wood and grass) and most other materials, such as rubber and plastic. Motor vehicles, power plant emissions and bushfires are all major sources of fine particles.

Health effects of PM10 particles

High levels of PM10 particles in the air can irritate the eyes and throat. People with existing heart or lung conditions (including asthma) can experience an increase in symptoms, including wheezing, chest tightness and difficulty breathing.

Sources of PM10 particles

Common sources of PM10 particles include sea salt, pollen and combustion activities such as motor vehicles and industrial processes. Dust from unsealed roads is a major source of PM10 particles.

Why Sofia,Bulgaria

More than 90% of air pollution-related deaths occur in low and middle-income countries, mainly in Asia and Africa, followed by low and middle-income countries of the Eastern Mediterranean region, Europe and the Americas.

Air quality in Bulgaria is a big concern: measurements show that citizens all over the country breathe in air that is considered harmful to health. For example, concentrations of PM2.5 and PM10 are much higher than what the EU and the World Health Organization (WHO) have set to protect health.

Bulgaria had the highest PM2.5 concentrations of all EU-28 member states in urban areas over a three-year average. For PM10, Bulgaria is also leading on the top polluted countries with 77 μg/m3on the daily mean concentration (EU limit value is 50 μg/m3).In 2017, Bulgaria was the first country to be sentenced by the EU Court of Justice to take action to improve air, and the country is still facing potential high fines.

According to the WHO, 60 percent of the urban population in Bulgaria is exposed to dangerous (unhealthy) levels of particulate matter (PM10).

In this project, visual analytics approach will be used for this project to reveal how Bulgarians are suffering from serious air pollution, explore their life pattern and possible reasons behind the severe social and health problem.

Tasks

Task 1: Spatio-temporal Analysis of Official Air Quality

Characterize the past and most recent situation with respect to air quality measures in Sofia City.

What does a typical day look like for Sofia city?
Do you see any trends of possible interest in this investigation?
What anomalies do you find in the official air quality dataset?
How do these affect your analysis of potential problems to the environment?

Task 2: Spatio-temporal Analysis of Citizen Science Air Quality Measurements

Characterize the sensors’ coverage, performance and operation.

Are they well distributed over the entire city?
Are they all working properly at all times?
Can you detect any unexpected behaviors of the sensors through analyzing the readings they capture?

Now turn your attention to the air pollution measurements themselves.

Which part of the city shows relatively higher readings than others?
Are these differences time dependent?

Task 3: Comprehensive view

Urban air pollution is a complex issue. There are many factors affecting the air quality of a city. Some of the possible causes are:

Local energy sources. For example, according to Unmask My City, a global initiative by doctors, nurses, public health practitioners, and allied health professionals dedicated to improving air quality and reducing emissions in our cities, Bulgaria’s main sources of PM10, and fine particle pollution PM2.5 (particles 2.5 microns or smaller) are household burning of fossil fuels or biomass, and transport.
Local meteorology such as temperature, pressure, rainfall, humidity, wind etc
Local topography
Complex interactions between local topography and meteorological characteristics.
Transboundary pollution for example the haze that intruded into Singapore from our neighbours.

The Data Sets

Four major data sets in zipped file format are provided for this assignment, they are:

Official air quality measurements (5 stations in the city)(EEA Data.zip) – as per EU guidelines on air quality monitoring see the data description HERE…
Citizen science air quality measurements (Air Tube.zip) , incl. temperature, humidity and pressure (many stations) and topography (gridded data).
Meteorological measurements (1 station)(METEO-data.zip): Temperature; Humidity; Wind speed; Pressure; Rainfall; Visibility
Topography data (TOPO-DATA)

They can be download by click on this link.