Enhanced nitrate contribution to light extinction during haze pollution in Chengdu: Insights based on an improved multiple linear regression model.
Environ Pollut
; 323: 121309, 2023 Apr 15.
Article
en En
| MEDLINE
| ID: mdl-36822310
ABSTRACT
In recent years, the annual mean concentration of PM2.5 has decreased in Chengdu, China; however, atmospheric visibility has not improved accordingly. Low-visibility events occurred even when the PM2.5 mass concentrations were below the national ambient air quality secondary standard (daily mean concentration, 75 µg/m3). In this study, the non-linear relationship between PM2.5 and visibility was analyzed under different NO3- mass fractions in PM2.5 based on 2-year field observation data. The results indicated that NO3- formation contributed to particulate pollution events and reduced atmospheric visibility. Multiple linear regression was used to propose a localized reconstruction equation for the light-scattering coefficient. According to the maximum likelihood estimation method and log-transformed residuals, the mass scattering coefficients (MSEs) of organic matter (OM), NH4NO3, and (NH4)2SO4 in Chengdu were 7.42, 3.83, and 3.80, respectively. OM and NH4NO3 contributed to more than 50% of the light-extinction coefficient (bext). NH4NO3 was the main pollutant causing the substantial increase in bext. Chengdu has a high relative humidity (annual mean 70%), and under such conditions, the contribution of NH4NO3 to bext was considerably enhanced through hygroscopic growth and heterogeneous reactions. This study estimated the localized MSEs of OM, NH4NO3, and (NH4)2SO4 in Chengdu and emphasized that effective control measures to reduce nitrate and its precursors could simultaneously ameliorate air quality and visibility in humid regions with poor atmospheric visibility.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Contexto en salud:
2_ODS3
Problema de salud:
2_quimicos_contaminacion
Asunto principal:
Contaminantes Atmosféricos
/
Contaminación del Aire
País/Región como asunto:
Asia
Idioma:
En
Revista:
Environ Pollut
Asunto de la revista:
SAUDE AMBIENTAL
Año:
2023
Tipo del documento:
Article
País de afiliación:
China