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

. 2020 Feb 28;7(8):1331–1339. doi: 10.1093/nsr/nwaa032

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

© The Author(s) 2020. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

PMC Copyright notice

Figure 4. — Variation of (a) mass concentration in NR_PM₁ and (b) mass fraction of organic, nitrate, sulfate, ammonium and chloride during heating seasons from 2013 to 2017.