Abstract:
Background PM2.5 as an important part of haze has attracted extensive attention from the whole society. Analyzing the sources, pollution characteristics, and pollution degrees of heavy metal components in PM2.5 in northern cities during heating and non-heating periods can help relevant government departments take intervention measures to improve air quality and protect people's health.
Objective This study analyzes the characteristics of heavy metal pollution in atmospheric PM2.5 during heating and non-heating periods in main urban area of Jinan, and evaluates the pollution degrees and potential ecological risks in different periods.
Methods The data of atmospheric PM2.5 level in main urban area in Jinan were collected from 2016 to 2017. Two air monitoring sites were set to collect the samples of PM2.5 every month. Ten metal elements were detected by inductively coupled plasma-mass spectrometry, including Sb, Pb, As, Mn, Hg, Cd, Ni, Cr, Se, and Tl. The sources, pollution degrees, and ecological risks of heavy metals in ambient PM2.5 during heating period and non-heating period were evaluated using enrichment factor (EF), index of geo-accumulation (I-geo), and potential ecological risk index (RI).
Results The daily PM2.5 concentrations ranged from 10.1 to 331.6 μg/m3 in the main urban area during 2016-2017. A total of 354 PM2.5 samples were collected, including 134 samples in heating period and 220 samples in non-heating period. Except Be, Ni, and Cr, the concentrations of the other heavy metals in heating period were higher than the concentrations in non-heating period. By enrichment factor method, except Be, Ni, and Cr, the other heavy metal pollution was from anthropogenic sources. The EFM (range) of Sb, Cd, Pb, Se, Tl, and As were 98.6 (72.6-121.0), 261.8 (193.8-367.1), 55.5 (41.9-69.5), 587.7 (441.6-756.9), 28.6 (22.1-37.0), and 14.6 (9.6-22.4) in heating period, and 87.8 (61.5-111.6), 228.5 (140.0-350.9), 45.0 (32.5-57.6), 659.6 (495.6-853.5), 29.3 (20.0-41.0), and 16.0 (10.6-22.9) in non-heating period, respectively. The ambient air in the target area was generally polluted by Cd, Sb, Pb, and Mn, and the pollution degrees were higher in heating period than in non-heating period. The potential ecological risk of Cd was high, and the risks of As, Cr, Pb, and Ni were low. The integrated ecological risk of all heavy metals in PM2.5 was graded as severe.
Conclusion PM2.5 pollution and heavy metal pollution are serious in the main urban area of Jinan. The enrichment, pollution, and ecological risk levels of some heavy metals in PM2.5 are higher in heating period than in non-heating period, which would have adverse health impacts.
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