Seasonal Variability of Air Pollutants and Their Relationships to Meteorological Parameters in an Urban Environment

Abstract

Air quality in urban areas is deteriorating over time with the increased pollutant distribution levels mainly caused due to anthropogenic activities. In addition, these pollutant distribution levels may relate to changing meteorological conditions. However, the relationships were not researched in-depth in the context of Sri Lanka, a country with a significant impact on climate change. The main objective of this study was to provide a broader perspective on the seasonal variation of tiny particles in air (PM2.5 and PM10), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and sulfur dioxide (SO2) in two urban cities (Colombo and Kandy) in Sri Lanka over 3 years period (2018–2021) and the possible relationships between air pollution and meteorological variables. Results show that all the aforementioned pollutants except O3 consistently depict two peaks during the day, one in the morning (∼07:00–09:00 local time) and the other in the evening (∼18:00–20:00 local time). These peaks coincided with the traffic jams observed in both cities. The results further revealed that the concentration of all pollutants has significant seasonal variations. Compared to two monsoon seasons, the highest daily average PM2.5 (31.2 μg/m3), PM10 (49.5 μg/m3), NO2 (18.9 ppb), CO (717.5 ppb), O3 (18.5 ppb), and SO2 (9.4 ppb) concentrations in Colombo are recorded during northeast monsoon (NEM) seasons while contrast pattern is observed in Kandy. In addition, it was found that wind speed with its direction is the most influencing factor for the pollutant concentration except for SO2 and O3 in two cities, and this is irrespective of the season. This study’s findings contribute to understanding the seasonality of ambient air quality and the relationship between meteorological factors and air pollutants. These findings ultimately lead to designing and implementing season-specific control strategies to achieve air pollution reduction at a regional scale.

Assessment of the Effect of Meteorological Conditions on the Concentration of Suspended PM2.5 Particulate Matter in Central Europe

“…This explains the substantial differences in the PM 2.5 concentrations between calendar seasons (spring, summer, autumn, and winter). Understanding seasonal variation is important for managing air quality and implementing measures to reduce pollutant emissions, especially in regions prone to poor air quality in specific seasons [59]. Similar relationships were reported by Zuśka et al [51], who used PCA for concentrations of PM10 particulate matter in Nowy Sącz.…”

Spatiotemporal Variability of Urban Air Pollution in Bucharest City

“…In Bucharest, all air pollutants present a typical bimodal trend, with specific double peaks corresponding to the morning rush hours and nighttime, inversely correlated with the planetary boundary layer height and temperature variability. The diurnal bimodal trend of air pollutants is also characteristic of other cities [28,58]. Moreover, the diurnal variation in PM 10 is strongly influenced by human activities, such as emissions from moving vehicles, construction, and industry, but also other anthropogenic sources.…”

Simulation of Submicron Particulate Matter (PM1) Dispersion Due to Traffic Rerouting to Establish a Walkable Cultural Tourism Route in Ratchaburi’s Old Town, Thailand

“…VRATE is principally obtained by multiplying the wind speed by the height of the planetary boundary layer (PBL). Hence, a combination of high wind-speed and high PBL promotes good ventilation, resulting in better dispersion conditions and allowing PM1 to be diluted [56,57]. The results of the correlations of PM1 and the dynamic atmospheric parameters imply that the R-LINE model yielded reasonable results.…”