Climatology of Discomfort Index and Air Quality Index in a Large Urban Mediterranean Agglomeration

Abstract

The paper studies the climatology of the Discomfort Index (DI) and the Common Air Quality Index (CAQI) in a large Mediterranean urban center (Greater Thessaloniki Area), examines the relations between the indices and the climatic conditions in the study area and investigates the linkage between the Urban Heat Island (UHI) effect and the enhanced discomfort and poor air quality in the city center. Discomfort conditions are more enhanced during July and August. Atmospheric conditions when the population suffers discomfort and feels severe stress are found mainly in the summer season hours with total frequency that can be up to about 4% in a month. Throughout the year, air quality conditions are unhealthier in the stations of urban characterization. Very high daily CAQI values are more frequent during the cold period (about 14%) than during the warm period (1-2%) of the year in the urban stations. Daily DI≥24°C could be more associated to increased temperature than relative humidity and is strongly related to high and very high CAQI values. During summer, when daily CAQI is ≥76, the feeling of discomfort is the most probable. Consequently, a strong synergy between discomfort and bad air quality exists in summertime. High and very high CAQI values and the discomfort feeling by the majority of the population are related to stagnant atmospheric conditions. During summer season, the poor air quality and the unfavorable comfort conditions for the majority of the population in the city center are associated with the greater frequency of a more intense UHI effect. The above phenomenon is more pronounced during nighttime than daytime.

Effects of Urbanization and Seasonal Cycle on the Surface Urban Heat Island Patterns in the Coastal Growing Cities: A Case Study of Casablanca, Morocco

“…Indeed, a study focused on the evaluation of SUHI in 25 cities around the Mediterranean, from 2001 to 2012, shows that the Southern European cities are affected by positive SUHII, While negative SUHII dominate the Mediterranean cities in Northern Africa [128]. On the other hand, UHI in European Mediterranean cities remain in the most cases influenced by urbanization factor such as the Greater Athens Area [129] and Thessaloniki [130], and is associated to the poor air quality and unfavorable comfort conditions [131].…”

Variability of Human-Biometeorological Conditions in Gdańsk

“…According to research, the UHI effect is responsible not only for unfavorable thermal conditions, but also an increase in concentrations of air pollutants [34,47,48]. the aforementioned fact was also found by Czarnecka and Nidzgorska-Lencewicz [36] for Gdańsk.…”

“…People sensitive to heat waves are, to a great extent, also vulnerable to episodes of air pollution, and when the two environmental conditions occur at the same time the health risk increases markedly. Such situations occur most frequently in the summer period and in cities they are additionally reinforced by the UHI effect [34][35][36]. Therefore, in order to have a wider picture of the onerous conditions occurring within the Gdańsk metropolitan area, the second part of the study includes an assessment of air quality made with using the CAQI index.…”

“…The conducted analysis shows that frequency of particular UTCI classes in Gdańsk is closely connected with the location of the measuring station -in the center of Gdańsk (W) thermal stress die to excess of "heat" occurs most frequently, whereas in the suburbs of Gdańsk (J) stress due to excess of "cold" is predominant. This fact is widely ascertained in the literature on the subject and results from, among other factors, the thermal privilege of the city center, which is a consequence of UHI [34,43]. The study by Sikora [44] conducted on the basis of an episode of hot weather of 3-days duration shows that in the city center the conditions of heat stress occur with frequency of 78% -at the same time the frequency in suburban areas is 58%.…”

Investigation and Forecasting of the Common Air Quality Index in Thessaloniki, Greece

“…Various air quality indices have been suggested by institutes and authorities in various countries [6], [7]. The European Environment Agency has adopted an index called the Common Air Quality Index (CAQI, www.eyeonearth.org) to identify the atmospheric quality towards public safety and health.…”