Origin of high particle number concentrations reaching the St. Louis, Midwest Supersite

• Published in: Journal of environmental sciences (China) 2015-08, Vol.34 (8), p.219-231
• Main Authors: de Foy, Benjamin, Schauer, James J.
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Atmospheric aerosols; Cities; Environmental Monitoring; Fine particles; Meteorology; Missouri; Mobile source emissions; Models, Theoretical; Nitrogen Oxides - analysis; Particle number concentrations; Particulate Matter - analysis; Regression Analysis; Seasons; Sulfur Dioxide - analysis; Sulfur dioxide plumes; TNC; 中西部; 健康影响; 多元回归分析; 时间序列; 粒子数浓度; 起源; 超细颗粒
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2014.12.026

Ultrafine particles are associated with adverse health effects. Total Particle Number Concentration（TNC） of fine particles were measured during 2002 at the St. Louis — Midwest supersite. The time series showed overall low level with frequent large peaks. The time series was analyzed alongside criteria pollutant measurements and meteorological observations. Multiple regression analysis was used to identify further contributing factors and to determine the association of different pollutants with TNC levels. This showed the strong contribution of sulfur dioxide（SO2） and nitrogen oxides（NO x） to high TNC levels. The analysis also suggested that increased dispersion resulting from faster winds and higher mixing heights led to higher TNC levels. Overall, the results show that there were intense particle nucleation events in a SO2 rich plume reaching the site which contributed around 29% of TNC. A further 40% was associated with primary emissions from mobile sources. By separating the remaining TNC by time of day and clear sky conditions,we suggest that most likely 8% of TNC are due to regional nucleation events and 23% are associated with the general urban background.