Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2022 Jul 19;67(17):1745–1749. doi: 10.1016/j.scib.2022.07.021

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2022 Science China Press. Published by Elsevier B.V. and Science China Press.

Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre - including this research content - immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

PMC Copyright notice

Fig. 2 — IASI (Infrared Atmospheric Sounding Interferometer) satellite observed NH₃ columns (in unit of molecule cm⁻²) over the five regions of China during the pre-COVID period, the COVID-lockdown period, and the COVID-lockdown minus pre-COVID differences in 2020. The five regions included Northeast (Heilongjiang, Jilin, and Liaoning), Southeast (Jiangsu, Anhui, Hubei, Shanghai, Zhejiang, Hunan, Jiangxi, Fujian, Guangxi, Hainan, and Guangdong), Northwest (Inner Mongolia, Xinjiang, Gansu, Shaanxi, Ningxia, Qinghai, and Tibet), Southwest (Sichuan, Chongqing, Yunnan, and Guizhou), North China Plain (Hebei, Henan, Beijing, Shanxi, Shandong, and Tianjin).