Long-Term Variation of Black Carbon Aerosol in China Based on Revised Aethalometer Monitoring Data

Abstract

<jats:p>Black carbon (BC) aerosol, as a typical optical absorption aerosol, is of great significance to the study of climate and radiation. The China Atmosphere Watch Network (CAWNET), established by the China Meteorological Administration (CMA), contains 35 BC-monitored stations, which have been collecting data using commercial Aethalometer instruments (AEs) since 2006. Element carbon (EC) data measured from the thermal/optical reflectance (TOR) method was used to correct the BC monitoring data from the AEs, which are affected by various sampling and analytical artifacts. The average difference before and after the revision was about 17.3% (±11.5%). Furthermore, we analyzed the variations of BC in China from 2006 to 2017 using a revised dataset. The ten-year averaged concentration of BC would have been applicable for climate analysis, and can be a comparison sample in future research. The concentrations of BC across the stations in China showed a general downward trend, with occasional fluctuations, and the concentrations at urban sites decreased more significantly. The average concentrations of BC in urban sites are higher than rural and remote sites. The 10-year averaged concentration of BC ranges from 11.13 μg m−3 in Gucheng to 0.19 μg m−3 in Shangri-La, showing a strong spatial variation; the proportion of BC aerosol in PM2.5 is generally less than 20%. The BC showed obvious seasonal and diurnal variation; and the highest concentration occurred in winter, with more dramatic diurnal variation, followed by autumn and spring. There was a significant increase in concentration between local time 7:00–9:00 and 18:00–0:00. The distribution and trend of BC concentration in China showed a consistency with emissions of BC.</jats:p>

Temporal Variability of Equivalent Black Carbon Components in Atmospheric Air in Southern Poland

“…Taking into account the data from the entire measurement period, the strongest positive correlation was recorded for eBC, eBC ff , and eBC bb vs. CO (r = 0.84-0.87). A very high positive correlation between eBC and eBC fractions and CO was maintained both in the heating and non-heating season, which is typical for traffic-influenced urban monitoring sites [43,67]. However, in the non-heating season, slightly higher values of correlation coefficients were recorded for the relation eBC bb vs. CO (r = 0.83).…”

“…In order to estimate the influence of meteorological conditions on the distribution of eBC, eBC ff , and eBC bb concentrations, a correlation matrix was prepared (Table 4). sites [43,67]. However, in the non-heating season, slightly higher values of correlation coefficients were recorded for the relation eBCbb vs. CO (r = 0.83).…”

“…It was found that-besides the seasonal variations-eBC, eBC ff , and eBC bb concentrations also exhibit pronounced diurnal variability, which could be associated with the combined effect of variations in the production of eBC, meteorology, and the associated boundary layer dynamics [23]. Distinct daily fluctuations in eBC concentrations were also identified at two research stations in Gucheng and Shangri-La, China [67].…”

“…To get m daily fluctuations of the concentrations of the 3 components under co eBC, eBCff, and eBCbb concentrations in monthly courses were present found that-besides the seasonal variations-eBC, eBCff, and eBCbb exhibit pronounced diurnal variability, which could be associated wi fect of variations in the production of eBC, meteorology, and the a layer dynamics [23]. Distinct daily fluctuations in eBC concentrations at two research stations in Gucheng and Shangri-La, China [67]. The lowest levels of eBC were recorded in the afternoon and fr and they did not exceed 1 µg•m −3 .…”

Interaction of Air Pollution with Snow and Seasonality Effects

“…Field observation, laboratory-experimental, and modeling studies are included, along with environmental monitoring and source apportionment research of local, regional, or global relevance. The fieldwork covered in the articles was conducted in various types of locations: urban sites (e.g., the cities of Chengdu, Gucheng [1], Helsinki [2], Montreal [3], and Moscow [4]); small cities and rural areas (e.g., Yulin, Huimin, and Zhengzhou [1], Tien Shan [5], Valday [6], and "36 sites on a 2800 km submeridional profile from the city of Barnaul to Salekhard" [7]); industrial [6]; remote (e.g., the Arctic, Antarctic [8], and Tibetan Plateau [9]); and other locations (e.g., along highways [10] and in the mountains [11]).…”