Los Angeles Basin's air quality transformation: A long-term investigation on the impacts of PM regulations on the trends of ultrafine particles and co-pollutants

被引：0

作者：

Badami, Mohammad Mahdi ^{[1
]}

Tohidi, Ramin ^{[1
]}

Sioutas, Constantinos ^{[1
,2
]}

机构：

[1] Univ Southern Calif, Dept Civil & Environm Engn, Los Angeles, CA USA

[2] Univ Southern Calif, Civil & Environm Engn, 3620 S Vermont Ave KAP210, Los Angeles, CA 90089 USA

来源：

JOURNAL OF AEROSOL SCIENCE | 2024年 / 176卷

基金：

美国国家卫生研究院;

关键词：

Ultrafine particles; Emission regulations; Particle number concentration; Vehicle miles traveled; NO x emissions; Policy impacts; PARTICULATE MATTER PM2.5; NUMBER CONCENTRATIONS; CHEMICAL-COMPOSITION; SOURCE APPORTIONMENT; EMISSIONS REDUCTION; NITROGEN-DIOXIDE; CARBON-MONOXIDE; CLIMATE-CHANGE; BLACK CARBON; AMBIENT AIR;

D O I：

10.1016/j.jaerosci.2023.106316

中图分类号：

TQ [化学工业];

学科分类号：

0817 ;

摘要：

This study investigates the long-term trends of ambient ultrafine particles (UFPs) and associated airborne pollutants in the Los Angeles Basin from 2007 to 2022, focusing on the indirect effects of regulations on UFP levels. The particle number concentration (PNC) of UFPs was compiled from previous studies in the area, and associated co-pollutant data, including nitrogen oxides (NOx), carbon monoxide (CO), elemental carbon (EC), organic carbon (OC), and ozone (O3), were obtained from the chemical speciation network (CSN) database. Over the study period, a general decrease was noted in the PNC of UFPs, NOx, EC, and OC, except for CO, the concentration trends of which did not exhibit a consistent pattern. UFPs, NOx, EC, and OC were positively correlated, while O3 had a negative correlation, especially with NOx. Our analysis discerned two distinct sub periods in pollutant trends: 2007-2015 and 2016-2022. For example, there was an overall decrease in the PNC of UFPs at an annual rate of-850.09 particles/cm3/year. This rate was more pronounced during the first sub-period (2007-2015) at-1814.9 particles/cm3/year and then slowed to-227.21 particles/cm3/year in the second sub-period (2016-2023). The first sub period (2007-2015) significantly influenced pollutant level changes, exhibiting more pronounced and statistically significant changes than the second sub-period (2016-2022). Since 2016, almost all primary pollutants have stabilized, indicating a reduced impact of current regulations, and emphasizing the need for stricter standards. In addition, the study included an analysis of Vehicle Miles Traveled (VMT) trends from 2007 to 2022 within the Los Angeles Basin. Despite the general increase in VMT, current regulations and cleaner technologies seem to have successfully mitigated the potential increase in increase in PNC. Overall, while a decline in UFPs and co-pollutant levels was observed, the apparent stabilization of these levels underscores the need for more stringent regulatory measures and advanced emission standards.

引用

页数：12