ISSS608 2018-19 T1 Assign Yan Huilin

Task 1

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

2013 has 2 days of heavily polluted days, about 10 days of medium polluted days, total polluted rate, medium.

2014 has 4 days of heavily polluted days, about 35 days of medium polluted days, total polluted rate, medium.

2015 has 6 days of heavily polluted days, about 45 days of medium polluted days, total polluted rate, high.

2016 has 1 days of heavily polluted days, about 1 days of medium polluted days, total polluted rate, very low.

2018 has 5 days of heavily polluted days, about 6 days of medium polluted days, total polluted rate, low.

From 2013 to 2015, the polluted days increased, thus the pollution level became higher. In 2016 however, the concentration plumped, and there was very few polluted day across the year. In 2018, the polluted days increased a bit at the beginning of the year, but stayed modest-polluted to the middle of September.

What does a typical day look like for Sofia city:

Condensation: 1500 – 7500

Trends of possible interests:

In 2013, the polluted days were in the early January and the late December. In 2014 and 2015, the polluted days were in January, February, November and December. In 2016, the only heavily polluted day was in January. In 2018, the polluted days were in January. Early or late of the year are the times that Sofia City most likely to be polluted.

Anomalies found:

1) Different duration data type: day or hour. From 2013 to 2015, the [ average time ] is day, while from 2016 onwards, the [ average time ] is hour.

2) 2017 data is not available: It only contains data from 2017.11.28 to 2017.12.31.

Potential problems of the anomalies:

1) When conducting year comparison, the different time dimension will affect the feasibility of tableau functions.

2) Since lost track of the data of one single year. Cannot get full view of the pollution trends and the understanding of the pollution pattern may also be flawed.