Characterization of Background Aerosol Properties during a Wintertime Smog Episode

Abstract

The aim of this paper is to study the wintertime physical properties of atmospheric aerosol particles on the basis of data observed at the K-puszta regional background station in Hungary. In Hungary wintertime smog episodes are linked to strong stable air (high pressure blocking events) with thermal inversion. These atmospheric conditions are frequently formed during winter months (November-February) due to the special geographical location of the country. The formation of smog events is highly probable in cases of thermal inversion periods sustaining for at least 4 days. We discuss in the paper the role of high-pressure blocking events in aerosol properties in terms of PM 10 concentrations, aerosol size distributions, new particle formation and optical properties. We found that high-pressure blocking events have significant impacts on the size distribution and particle formation processes. At K-puszta the aerosol is in highly aged state with size distribution dominated by the accumulation mode. This is further supported by the optical properties, e.g., by high scattering Ångstrom exponent and by relatively weak absorption. The most significant effect of extreme episodes is manifested in the changes in PM 10 concentrations and, consequently, in aerosol optical properties. The PM 10 concentrations, scattering coefficients and absorption coefficients considerably increase to extreme values that are characteristic of a heavily polluted atmosphere rather than rural air. Our results indicate that in winter, the air quality at Kpuszta is often influenced by regional air pollution as shown by spatial distribution of PM 10 concentration. It is found that PM 10 had almost the same concentration in regional background air and in different types of urban environments. The special meteorological conditions and the role of regional-scale transport can explain why local abatements in cities cannot lead to significant improvement of the air quality during smog events.

Reply to Referee#1

“…At both IPR and KPS, the frequent wintertime episodes, linked to stable air due to strong thermal inversions, affect the level of pollution at these sites (e.g. Putaud et al, 2014;Molnár et al, 2016). It is known that the IPR station, despite lying several tens of kilometres away from large pollution sources, is located in an area (the Po Valley) which is one of the most polluted regions in Europe (e.g.…”

Adverse impacts of fog events during winter on fine particulate matter, CO and VOCs: a case study of a highway near Dhanbad, India

“…It affected people in several ways, including respiratory discomfort, eye pain, nausea and vomiting (Sharma et al ., ). From the first appearance of the London smog until recent times, wintertime fog/haze is a well‐known phenomenon which affects atmospheric conditions all over the world (Ram et al ., ; Guo et al ., ; Jiang et al ., ; Molnar et al ., ).…”

“…Measurements of particle mass/number size distributions have been conducted in many Asian, European and US cities and countries, for example Nanjing (Kang et al ., ), the North China Plain (Quan et al ., ), Beijing (Liu et al ., ), Zhongmu (Yu et al ., ), Hungary (Molnar et al ., ), Paris (Hammer et al ., ) and Pittsburgh (Stanier et al ., ). In those studies, particle number concentrations were higher during fog/haze events.…”

Assessment of air pollution in exercise centers and health risks

“…Human and natural resources are the sources of particles diffusion in the atmosphere. Fossil fuels in the transportation sector, factories, and manufacturing industries are the sources of particles diffusion in the human sector (1)(2)(3). According to the World Health Organization (WHO), by reducing airborne pollutants from 70 to 20 µg/ m 3 in the atmosphere, the mortality rate can be reduced by 15% (4).…”