Patterns and Influencing Factors of Air Pollution at a Southeast Chinese City

Ambient air pollution is a pressing global environmental problem. To identify the source of air pollution and manage air quality in urban areas, the patterns of air pollutants under different traffic conditions and the impact of weather on air quality were explored in Hangzhou, China, a city experiencing rapid growth in vehicles. Data for particulate matters (PM10, PM2.5, PM1.0, and UFP), gaseous pollutants (CO, SO2, O3, and NO), and weather parameters (temperature, relative humidity, wind speed, and air pressure) were collected at two venues with different traffic conditions. An exploratory factor analysis was employed to identify the main factors contributing to air quality. The results showed that PMs, particularly PM1.0 and UFP, significantly contributed to air quality in monitoring venues, especially at Venue 2. As the leading factor, PMs contributed 40.85%, while gaseous pollutants and traffic (particularly fuel type) contributed 30.46% to air quality. The traffic was an independent contributor at Venue 2. Temperature and wind speed had negative influences on air pollutants. The outcomes of the study suggest that exhaust emissions from vehicles, particularly PM1.0 and UFP from heavy-duty vehicles, contributed significantly to ambient air quality. The contribution of meteorological factors to air quality varied at different venues and should not be ignored.