Wet deposition of inorganic ions in 320 cities across China: spatio-temporal variation, source apportionment, and dominant factors
oleh: R. Li, L. Cui, Y. Zhao, Z. Zhang, T. Sun, J. Li, W. Zhou, Y. Meng, K. Huang, H. Fu, H. Fu, H. Fu
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2019-09-01 |
Deskripsi
<p>The acid deposition has been considered to be a severe environmental issue in China. The pH, electrical conductivity (EC), and concentrations of water soluble ions (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="57a4663cbf0d11bf294d99bb32c9ae29"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00001.svg" width="25pt" height="16pt" src="acp-19-11043-2019-ie00001.png"/></svg:svg></span></span>, <span class="inline-formula">Cl<sup>−</sup></span>, <span class="inline-formula">Ca<sup>2+</sup></span>, <span class="inline-formula">K<sup>+</sup></span>, <span class="inline-formula">F<sup>−</sup></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NH</mi><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="6ca56caa63735c5009fe6b299c1a126b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00002.svg" width="24pt" height="15pt" src="acp-19-11043-2019-ie00002.png"/></svg:svg></span></span>, <span class="inline-formula">Mg<sup>2+</sup></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="40da026c69d6bb7b362f8aefb7758b92"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00003.svg" width="29pt" height="17pt" src="acp-19-11043-2019-ie00003.png"/></svg:svg></span></span>, and Na<span class="inline-formula"><sup>+</sup>)</span> in the precipitation samples collected from 320 cities during 2011–2016 across China were measured. The mean concentrations of <span class="inline-formula">F<sup>−</sup></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M11" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="eb51cd45ba2a21283d090226a04e61ba"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00004.svg" width="25pt" height="16pt" src="acp-19-11043-2019-ie00004.png"/></svg:svg></span></span>, and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="97cb19aa5ca8b26a6d7fd7d4bad307d2"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00005.svg" width="29pt" height="17pt" src="acp-19-11043-2019-ie00005.png"/></svg:svg></span></span> were in the order of winter (6.10, 19.44, and 45.74 <span class="inline-formula">µ</span>eq L<span class="inline-formula"><sup>−1</sup></span>) <span class="inline-formula">></span> spring (3.45, 13.83, and 42.61 <span class="inline-formula">µ</span>eq L<span class="inline-formula"><sup>−1</sup></span>) <span class="inline-formula">></span> autumn (2.67, 9.73, and 28.85 <span class="inline-formula">µ</span>eq L<span class="inline-formula"><sup>−1</sup></span>) <span class="inline-formula">></span> summer (2.04, 7.66, and 19.26 <span class="inline-formula">µ</span>eq L<span class="inline-formula"><sup>−1</sup></span>). Secondary ions (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M24" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="a37f0080584a5af55d602bece406075e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00006.svg" width="29pt" height="17pt" src="acp-19-11043-2019-ie00006.png"/></svg:svg></span></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M25" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="361af9fc60c163df468716a068868655"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00007.svg" width="25pt" height="16pt" src="acp-19-11043-2019-ie00007.png"/></svg:svg></span></span>, and NH<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M26" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi/><mn mathvariant="normal">4</mn><mo>+</mo></msubsup><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="12pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="d53ad71897ec3c7fd0dc998c7ef3cc8c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00008.svg" width="12pt" height="15pt" src="acp-19-11043-2019-ie00008.png"/></svg:svg></span></span> and <span class="inline-formula">F<sup>−</sup></span> peaked in the Yangtze River Delta (YRD) and Sichuan basin (SB). Crustal ions (i.e. <span class="inline-formula">Ca<sup>2+</sup></span>, <span class="inline-formula">Mg<sup>2+</sup></span>), <span class="inline-formula">Na<sup>+</sup></span>, and <span class="inline-formula">Cl<sup>−</sup></span> showed the highest concentrations in the semi-arid regions and the coastal cities. The statistical methods confirmed that the mean anthropogenic contribution ratios to <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M32" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="ffbe05c8ea0f1e229c212e21ef64f69c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00009.svg" width="29pt" height="17pt" src="acp-19-11043-2019-ie00009.png"/></svg:svg></span></span>, <span class="inline-formula">F<sup>−</sup></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M34" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="983e472baa2b1950fa497a555dcc7b2e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00010.svg" width="25pt" height="16pt" src="acp-19-11043-2019-ie00010.png"/></svg:svg></span></span>, and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M35" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NH</mi><mn mathvariant="normal">4</mn><mo>+</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="24pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="57b95c61d17fec970641a3dc090ae78a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00011.svg" width="24pt" height="15pt" src="acp-19-11043-2019-ie00011.png"/></svg:svg></span></span> at a national scale were 46.12 %, 71.02 %, 79.10 %, and 82.40 %, respectively. However, <span class="inline-formula">Mg<sup>2+</sup></span> (70.51 %), <span class="inline-formula">K<sup>+</sup></span> (77.44 %), and <span class="inline-formula">Ca<sup>2+</sup></span> (82.17 %) mostly originated from the crustal source. Both <span class="inline-formula">Na<sup>+</sup></span> (70.54 %) and <span class="inline-formula">Cl<sup>−</sup></span> (60.42 %) were closely linked to sea salt aerosols. On the basis of the stepwise regression (SR) analysis, it was proposed that most of the secondary ions and <span class="inline-formula">F<sup>−</sup></span> were closely related to gross industrial production (GIP), total energy consumption (TEC), vehicle ownership, and N fertilizer use, but the crustal ions (<span class="inline-formula">Ca<sup>2+</sup></span> and <span class="inline-formula">K<sup>+</sup></span>) were mainly controlled by the dust events. The influence of dust days, air temperature, and wind speed on ions increased from southeast China (SEC) to central China, and then to northwest China (NWC), whereas the influence of socioeconomic factors on acid ions (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M44" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">SO</mi><mn mathvariant="normal">4</mn><mrow><mn mathvariant="normal">2</mn><mo>-</mo></mrow></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="1351e966e04bfc1e60ff4784424cad14"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00012.svg" width="29pt" height="17pt" src="acp-19-11043-2019-ie00012.png"/></svg:svg></span></span> and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M45" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msubsup><mi mathvariant="normal">NO</mi><mn mathvariant="normal">3</mn><mo>-</mo></msubsup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="afc29ccf929971927e195b135fd5e45c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-19-11043-2019-ie00013.svg" width="25pt" height="16pt" src="acp-19-11043-2019-ie00013.png"/></svg:svg></span></span>) displayed the higher value in east China.</p>